Changes in nutrients and food groups intake following laparoscopic Roux-en-Y gastric bypass (RYGB)

Change in carbohydrate intake one year after Roux-en-Y gastric bypass: A prospective study

Background and objectives: To investigate the effect of carbohydrate intake before laparoscopic Roux-en-Y gastric bypass (LRYGB) on body weight, body composition and glycaemic status after surgery. Methods: In a tertiary centre cohort study, dietary habits, body composition and glycaemic status were evaluated before and 3, 6 and 12 months after LRYGB. Detailed dietary food records were processed by specialized dietitians on the basis of a standard protocol. The study population was subdivided according to relative carbohydrate intake before surgery. Results: Before surgery, 30 patients had a moderate relative carbohydrate intake (26%-45%, M-CHO), a mean body mass index (BMI) of 40.4 ± 3.9 kg/m² and a mean glycated haemoglobin A1c (A1C) of 6.5 ± 1.2% compared to 20 patients with a high relative carbohydrate intake (> 45%, H-CHO), mean BMI of 40.9 ± 3.7 kg/m² (non-significant, NS) and a mean A1C of 6.2% (NS). One year after surgery, body weight, body composition and glycaemic status were similar in the M-CHO (n = 25) and H-CHO groups (n = 16), despite less caloric intake in the H-CHO group (1317 ± 285 g vs. 1646 ± 345 g in M-CHO, p < 0.01). Their relative carbohydrate intake converged to 46% in both groups, but the H-CHO group reduced the absolute total carbohydrate consumption more than the M-CHO group (190 ± 50 g in M-CHO vs. 153 ± 39 g in H-CHO, p < 0.05), and this was especially pronounced for the mono- and disaccharides (86 ± 30 g in M-CHO vs. 65 ± 27 g in H-CHO, p < 0.05). Conclusion: A high relative carbohydrate intake before LRYGB, did not influence the change in body composition or diabetes status after surgery, despite a significantly lower total energy intake and less mono- and disaccharide consumption after surgery.

Short-term impact of bariatric surgery on the dietary intake of patients with type 2 diabetes

BACKGROUND

The prevalence of overweight and obesity and an unhealthy diet and lifestyle are the key causes of rising diabetes burden in India. Bariatric surgery is gaining popularity in India as a favored approach to manage obesity and its accompanying comorbidities. Despite this, there is a scarcity of Indian studies evaluating dietary intake. Our goal was to analyse the dietary intake of Indian patients with type 2 diabetes mellitus (T2DM) who have undergone laparoscopic sleeve gastrectomy (LSG) or duodeno-jejunal bypass with sleeve gastrectomy (DJB-SG) or surgeries.

METHODS

The longitudinal observational study included 64 T2DM patients (32 in each procedure) enrolled through purposive sampling. The patients underwent surgery (LSG or DJB-SG procedure) between January 2017 and July 2019. Dietary data was collected at baseline and postsurgery (12 months) using a 24-h dietary recall method for 2 days (one working and one holiday).

RESULTS

The total sample consisted of 27 (42.2%) females and 37 (57.8%) males. The mean age was 46.8 years. At 12 months, the follow-up for the LSG and DJB-SG procedures was 100% and 78%, respectively. In the short term, a significant reduction was seen in weight, body mass index and haemoglobin A1C (HbA1C) in both surgical groups. The two procedures were comparable with respect to weight loss but improvement in glycaemia was higher in the DJB-SG group. The dietary intake (food groups and nutrients) was similar in the two surgical groups at baseline and 12 months postsurgery. Dietary intake assessment showed significant reduction in calorie dense foods (cereals, roots and tubers, fats and oils, table sugar, and biscuits) in both surgical groups. Among nutrients, intake of energy, fats, carbohydrates, dietary fibre, thiamine, riboflavin, niacin, folate and iron were reduced significantly in both procedures. Vitamin D (84.4% patients in LSG group and 81.3% patients in DJB-SG) and iron (62.5% patients in LSG group and 68.8% patients in DJB-SG) were commonly prevalent nutritional deficiencies at baseline and were significantly reduced at 12 months.

CONCLUSIONS

In the short term, bariatric surgery resulted in weight loss and improvement in glycaemia. Bariatric surgery does significantly affect dietary intake leading to nutritional deficiencies. Therefore, patients should be recommended vitamin and mineral supplements and regular patient education and counselling by a trained bariatric dietitian to prevent nutritional deficiencies and maintain nutritional status.

The Role of Dietary Intake in the Weight Loss Outcomes of Roux-en-Y Gastric Bypass and Sleeve Gastrectomy: A Systematic Review and Meta-analysis

The relationship between postoperative dietary intake and weight loss after bariatric surgery remains unclear. We performed a systematic review and meta-analysis of studies published between January 2000 and May 2023, reporting weight loss outcomes, and dietary intake before and after Roux-en-Y gastric bypass and sleeve gastrectomy. A total of 42 studies were included. There was no detectable difference in dietary intake between the two procedures. Roux-en-Y gastric bypass induced an average decrease in energy intake of 886 kcal/day at 12-month post-surgery; however, there was no correlation between daily energy intake and weight loss. These findings show a substantial reduction of energy intake in the first year after bariatric surgery but do not support a link between lower energy intake and greater weight loss.

Changes in nutrient composition and diet quality in the first 6 months following bariatric surgery: An observational cohort study

BACKGROUND

Bariatric surgery (BS) may result in inadequate nutrient intake and poor diet quality, which can lead to nutritional complications. The present study aimed to evaluate changes in macro- and micronutrient composition and diet quality in the first 6 months following BS.

METHODS

One hundred seven participants undergoing BS (Roux-en-Y gastric bypass: n = 87, sleeve gastrectomy: n = 20) completed 3-day food records before and 6 months after surgery. Changes in energy, macronutrient (carbohydrates, protein, fat, dietary fibre) and micronutrient intake (folate, vitamin B12, vitamin D, calcium, iron) were evaluated. Diet quality was assessed by adherence to the Dutch food-based dietary guidelines.

RESULTS

After BS, we observed a significant decrease in intake of energy and all macro- and micronutrients (p < 0.01 for all), except for calcium (-39.0 ± 404.6 mg; p = 0.32). Overall, nutrient composition slightly changed with an increase in the relative intake of protein (+1.1 ± 4.3 energy percentage [en%]; p = 0.01) and mono- and disaccharides (+4.2 ± 6.4 en%; p < 0.001) post-surgery. Consumption (median [Q1, Q3]) of vegetables (-50 [-120, 6] g day-1 ), wholegrain products (-38 [-81, -8] g day-1 ), liquid fats (-5 [-13, 2] g day-1 ), red meat (-3 [-30, 4] g day-1 ), processed meat (-32 [-55, 13] g day-1 ), sodium (-0.7 [-1.1, -0.2] g day-1 ) and unhealthy food choices (-2.4 [-5.0, 0.6] serves week-1 ) significantly decreased after BS (p < 0.01 for all).

CONCLUSIONS

Our results demonstrate both favourable and unfavourable changes in macro- and micronutrient composition and diet quality in the first 6 months following BS. Insight into these changes can improve dietary counselling in this population. Future research into underlying causes, consequences and long-term changes in dietary intake is needed.

Involvement of the vagus nerve in the anorectic effect of monoacylglycerol acyltransferase 2 inhibition in mice

Background

Many of the drugs used for obesity treatment have adverse effects on the central nervous system. Therefore, novel treatments, such as peripherally acting drugs, are needed. Monoacylglycerol acyltransferase 2 (MGAT2), highly expressed in the small intestine, catalyzes the first step of triacylglycerol re-synthesis. MGAT2 inhibition suppresses food intake in high-fat diet (HFD)-fed mice, but the mechanisms remain unclear. Here, the involvement of the vagus nerve in MGAT2 inhibition-induced feeding suppression was investigated.

Methods

Fasted mice were administered an MGAT2 inhibitor. Food intake was measured after HFD re-feeding, and the effect of capsaicin pretreatment on changes in food intake was evaluated. The number of c-fos-positive cells in the nucleus tractus solitarius and levels of appetite regulators were determined after HFD re-feeding or lipid gavage.

Results

The anorectic effect of the MGAT2 inhibitor was abolished when vagus nerve function was interrupted by capsaicin. MGAT2 inhibition increased the number of c-fos-positive cells in the nucleus tractus solitarius and elevated intestinal oleoylethanolamide, plasma peptide tyrosine-tyrosine and plasma glucagon-like peptide-1 levels.

Conclusion

MGAT2 inhibition suppresses feeding behavior via peripheral vagus nerve signaling and may serve as a novel anti-obesity strategy with a low risk of unexpected central nervous system-related adverse effects.

Development and complications of nutritional deficiencies after bariatric surgery

The clinical effectiveness of bariatric surgery has encouraged the use of bariatric procedures for the treatment of morbid obesity and its comorbidities, with sleeve gastrectomy and Roux-en-Y gastric bypass being the most common procedures. Notwithstanding its success, bariatric procedures are recognised to predispose the development of nutritional deficiencies. A framework is proposed that provides clarity regarding the immediate role of diet, the gastrointestinal tract and the medical state of the patient in the development of nutritional deficiencies after bariatric surgery, while highlighting different enabling resources that may contribute. Untreated, these nutritional deficiencies can progress in the short term into haematological, muscular and neurological complications and in the long term into skeletal complications. In this review, we explore the development of nutritional deficiencies after bariatric surgery through a newly developed conceptual framework. An in-depth understanding will enable the optimisation of the post-operative follow-up, including detecting clinical signs of complications, screening for laboratory abnormalities and treating nutritional deficiencies.

Associations Between Changes in Activity and Dietary Behaviors after Metabolic and Bariatric Surgery

INTRODUCTION

Patients who undergo metabolic and bariatric surgery (MBS) are advised to make healthy activity and dietary changes. While previous research has examined post-surgical changes in activity and dietary behaviors separately, no study has assessed whether changes in these behaviors are beneficially associated with each other. We evaluated whether post-surgical improvements in activity behaviors related to favorable changes in dietary behaviors overall and by surgery type (Roux-en-Y gastric bypass [RYGB], sleeve gastrectomy [SG]).

METHODS

At pre-surgery and 6- and 12-months post-surgery, participants (N = 97; 67 RYGB/30 SG) wore an accelerometer for 7 days and completed 24-h dietary assessments on 3 days. General linear models assessed associations between pre- to post-surgical changes in activity (moderate-to-vigorous physical intensity activity [MVPA], sedentary time [ST]) and dietary (total energy intake [EI; kcal/day], dietary quality [healthy eating index/HEI scores]) behaviors, with surgery type as a moderator.

RESULTS

Participants on average: demonstrated small, non-significant post-surgical changes in MVPA and ST minutes/day (ps > .05); and reported significant post-surgical decreases in EI (p < .001), but no changes in HEI scores (ps > .25). Greater 12-month post-surgical increases in MVPA were significantly associated with greater decreases in EI, but only for RYGB participants (p < .001).

DISCUSSION

Participants reported large decreases in EI, but made minimal changes in other behaviors after MBS. Results suggest greater increases in MVPA could assist with achieving greater decreases in EI, although this benefit appears to be limited to RYGB patients. Additional research is needed to confirm these findings and determine whether activity-dietary behavior associations differ beyond the immediate post-surgical year.

Longer-Term Weight Loss Outcomes Are Not Primarily Driven by Diet Following Roux-en-Y Gastric Bypass and Sleeve Gastrectomy

Metabolic and bariatric surgery (MBS) is the most effective long-term treatment for Class III obesity. Reduced dietary intake is considered a behavioral driver of post-surgical weight loss, but limited data have examined this association. Therefore, this study examined prospective, longitudinal relationships between dietary intake and weight loss over 24 months following Roux-en-Y Gastric Bypass and Sleeve Gastrectomy. Relationships between weight loss and dietary intake were examined using a validated 24-h dietary recall method. Associations between total energy/macronutrient intake and weight loss outcomes were assessed at 12-, 18-, and 24-months following MBS, defining patients as "responders" and "suboptimal responders". Consistent with previous literature, 12-month responders and suboptimal responders showed significant associations between weight loss and energy (p = 0.018), protein (p = 0.002), and total fat intake (p = 0.005). However, this study also revealed that many of these associations are no longer significant 24 months post-MBS (p > 0.05), despite consistent weight loss trends. This study suggests a short-term signal between these dietary factors and weight loss outcomes 12 months post-MBS; however, this signal does not persist beyond 12 months. These results are essential for interpreting and designing clinical studies measuring long-term post-surgical weight loss outcomes.

Nutritional Status, Selected Nutrients Intake, and Metabolic Disorders in Bariatric Surgery Patients

Bariatric surgery is the most effective treatment for obesity and its complications. However, failure to adhere to dietary recommendations can result in both unsatisfactory weight loss and metabolic disorders. The aim of this study was to evaluate the effects of bariatric surgery on the anthropometric parameters and selected nutrient intake. A total of 12 months postoperatively, percent excess weight loss (%EWL) was significantly higher after laparoscopic Roux-en-Y gastric bypass (LRYGB) than laparoscopic sleeve gastrectomy (LSG) and laparoscopic adjustable gastric banding (LAGB) (93.78% vs. 56.13% and 55.65%, p < 0.001). The same was true for waist-to-hip ratio (WHR) (p = 0.017) and waist-to-height ratio (WHtR) changes (p = 0.022). There was a significant decrease in total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels after RYGB. A significant decrease (p < 0.05) in daily intake was found for energy (4278.4 kcal vs. 1355.17 kcal), sucrose (122.23 g vs. 38.22 g), dietary fiber (30.90 g vs. 14.20 g), eicosapentaenoic fatty acid and docosahexaenoic acid (EPA+DHA) (142.46 mg vs. 52.90 mg) and % energy from fats (42.43% vs. 35.17%), saturated fatty acids (SAFAs) (19.96% vs. 14.11%) and alpha-linolenic fatty acid (ALA) (0.87% vs. 0.69%). Energy intake and energy % from fats positively correlated with body weight (BW), waist circumference (WC), WHR, and WHtR, and negatively with %EWL. The percentage of unsaturated fatty acids positively correlated with WC and WHR. Energy intake correlated positively with serum triglycerides (TGs) and energy % from fats and carbohydrates. Despite significant weight loss, the patient's diet deviated from recommendations and may have contributed to metabolic disorders.

Long-term changes in dietary intake and its association with eating-related problems after gastric bypass in adolescents

BACKGROUND

Roux-en-Y gastric bypass (RYGB) surgery is an established, effective treatment for severe adolescent obesity. Long-term dietary intake and the relationship to eating-related problems are scarcely evaluated in this population.

OBJECTIVES

Assess changes in dietary intake in adolescents after RYGB and explore associations between dietary intake and eating-related problems.

SETTING

Multicenter study in Swedish university hospitals.

METHOD

Diet history, binge eating scale (BES), and Three-Factor Eating Questionnaire were assessed preoperatively and 1, 2, and 5 years after RYGB in 85 adolescents (67% female) aged 16.5 ± 1.2 years with a body mass index (BMI) of 45.5 ± 6.0 kg/m² and compared with control individuals at 5 years.

RESULTS

Five-year BMI change was -28.6% ± 12.7% versus +9.9% ± 18.9% in RYGB patients versus control individuals (P < .001). Through 5 years, RYGB adolescents reported reduced energy intake, portion size of cooked meals at dinner, and milk/yoghurt consumption (P < .01). The BES scores were 9.3 ± 8.3 versus 13.4 ± 10.5 in RYGB patients versus control individuals (P = .04). Association between BES score and energy intake was stronger in control individuals (r = .27 versus r = .62 in RYGB patients versus control individuals, P < .001). At 5 years, lower energy intake was associated with greater BMI loss in all adolescents (r = .33, P < .001). Higher scores in BES and uncontrolled and emotional eating were associated with higher energy intake, cooked meals, candies/chocolates, cakes/cookies, desserts, and sugary drinks (r > .23, P < .04) and lower intake of fruits/berries (r = -.32, P = .044). A higher score in cognitive restraint was associated with a higher intake of cereals and fruits/berries (r > .22, P < .05) and a lower intake of sugary drinks (r = -.24, P < .03).

CONCLUSION

To support optimization of long-term outcomes in adolescent RYGB patients, it is important to provide management strategies to reduce energy intake. Monitoring eating-related problems could identify potential individuals at risk of poor weight loss and to initiate treatment interventions.

Potential associations between alterations in gut microbiome and obesity-related traits after the bariatric surgery

AIM

This study aimed to examine the effects of both obesity and bariatric surgery on gut microbiome, dietary intake, as well as metabolic and inflammatory parameters.

METHODS

All participants (15 with morbid obesity who had bariatric surgery, 8 with morbid obesity and 11 non-obese) were followed-up for a 6-month period with the interviews at baseline (M0), at the end of 3 (M3) and 6 months (M6). Dietary assessment was done, and blood and faecal samples were collected.

RESULTS

Dietary energy and nutrient intakes as well as serum levels glucose, total cholesterol, LDL-cholesterol, and hs-CRP levels decreased by surgery (p<0.05, for each). Participants with morbid obesity had higher levels of Firmicutes and lower levels of Bacteroidetes at M0 compared to non-obese participants. The abundances of Bacteroidetes increased (p=0.02) while Firmicutes decreased (p>0.05) by the surgery, leading a significant decrease in Firmicutes/Bacteroidetes ratio (p=0.01). At sub-phylum level, the abundances of Lactobacillus and Bifidobacterium decreased while Akkermansia increased by the surgery (p<0.01, for each). Although participants who are morbidly obese had a distinct profile according to ß-diversity indices at M0, it became similar with the profile of non-obese participants (p>0.05) at M3 and M6. Similarly, α-diversity indices were lower in subjects with morbid obesity at M0, but became similar to levels in non-obese controls at M6.

CONCLUSION

This study confirmed that bariatric surgery has substantial impacts on gut microbiome composition and diversity, as well as anthropometrical measurements and biochemical parameters, which were associated with the alterations in dietary intake patterns. This article is protected by copyright. All rights reserved.

Food Intake Following Gastric Bypass Surgery: Patients Eat Less but Do Not Eat Differently

BACKGROUND

Lack of robust research methodology for assessing ingestive behavior has impeded clarification of the mediators of food intake following gastric bypass (GBP) surgery.

OBJECTIVES

To evaluate changes in directly measured 24-h energy intake (EI), energy density (ED) (primary outcomes), eating patterns, and food preferences (secondary outcomes) in patients and time-matched weight-stable comparator participants.

METHODS

Patients [n = 31, 77% female, BMI (in kg/m²) 45.5 ± 1.3] and comparators (n = 32, 47% female, BMI 27.2 ± 0.8) were assessed for 36 h under fully residential conditions at baseline (1 mo presurgery) and at 3 and 12 mo postsurgery. Participants had ad libitum access to a personalized menu (n = 54 foods) based on a 6-macronutrient mix paradigm. Food preferences were assessed by the Leeds Food Preference Questionnaire. Body composition was measured by whole-body DXA.

RESULTS

In the comparator group, there was an increase in relative fat intake at 3 mo postsurgery; otherwise, no changes were observed in food intake or body composition. At 12 mo postsurgery, patients lost 27.7 ± 1.6% of initial body weight (P < 0.001). The decline in EI at 3 mo postsurgery (-44% from baseline, P < 0.001) was followed by a partial rebound at 12 mo (-18% from baseline), but at both times, dietary ED and relative macronutrient intake remained constant. The decline in EI was due to eating the same foods as consumed presurgery and by decreasing the size (g, MJ), but not the number, of eating occasions. In patients, reduction in explicit liking at 3 mo (-11.56 ± 4.67, P = 0.007) and implicit wanting at 3 (-15.75 ± 7.76, P = 0.01) and 12 mo (-15.18 ± 6.52, P = 0.022) for sweet foods were not matched by reduced intake of these foods. Patients with the greatest reduction in ED postsurgery reduced both EI and preference for sweet foods.

CONCLUSIONS

After GBP, patients continue to eat the same foods but in smaller amounts. These findings challenge prevailing views about the dynamics of food intake following GBP surgery. This trial was registered as clinicaltrials.gov as NCT03113305.

Does Bypass of the Proximal Small Intestine Impact Food Intake, Preference, and Taste Function in Humans? An Experimental Medicine Study Using the Duodenal-Jejunal Bypass Liner

The duodenal-jejunal bypass liner (Endobarrier) is an endoscopic treatment for obesity and type 2 diabetes mellitus (T2DM). It creates exclusion of the proximal small intestine similar to that after Roux-en-Y Gastric Bypass (RYGB) surgery. The objective of this study was to employ a reductionist approach to determine whether bypass of the proximal intestine is the component conferring the effects of RYGB on food intake and sweet taste preference using the Endobarrier as a research tool. A nested mechanistic study within a large randomised controlled trial compared the impact of lifestyle modification with vs. without Endobarrier insertion in patients with obesity and T2DM. Forty-seven participants were randomised and assessed at several timepoints using direct and indirect assessments of food intake, food preference and taste function. Patients within the Endobarrier group lost numerically more weight compared to the control group. Using food diaries, our results demonstrated similar reductions of food intake in both groups. There were no significant differences in food preference and sensory, appetitive reward, or consummatory reward domain of sweet taste function between groups or changes within groups. In conclusion, the superior weight loss seen in patients with obesity and T2DM who underwent the Endobarrier insertion was not due to a reduction in energy intake or change in food preferences.

Roux-en-Y Gastric Bypass and Caloric Restriction but Not Gut Hormone-Based Treatments Profoundly Impact the Hypothalamic Transcriptome in Obese Rats

BACKGROUND

The hypothalamus is an important brain region for the regulation of energy balance. Roux-en-Y gastric bypass (RYGB) surgery and gut hormone-based treatments are known to reduce body weight, but their effects on hypothalamic gene expression and signaling pathways are poorly studied.

METHODS

Diet-induced obese male Wistar rats were randomized into the following groups: RYGB, sham operation, sham + body weight-matched (BWM) to the RYGB group, osmotic minipump delivering PYY3-36 (0.1 mg/kg/day), liraglutide s.c. (0.4 mg/kg/day), PYY3-36 + liraglutide, and saline. All groups (except BWM) were kept on a free choice of high- and low-fat diets. Four weeks after interventions, hypothalami were collected for RNA sequencing.

RESULTS

While rats in the RYGB, BWM, and PYY3-36 + liraglutide groups had comparable reductions in body weight, only RYGB and BWM treatment had a major impact on hypothalamic gene expression. In these groups, hypothalamic leptin receptor expression as well as the JAK-STAT, PI3K-Akt, and AMPK signaling pathways were upregulated. No significant changes could be detected in PYY3-36 + liraglutide-, liraglutide-, and PYY-treated groups.

CONCLUSIONS

Despite causing similar body weight changes compared to RYGB and BWM, PYY3-36 + liraglutide treatment does not impact hypothalamic gene expression. Whether this striking difference is favorable or unfavorable to metabolic health in the long term requires further investigation.

A Comparison of Total Food Intake at a Personalised Buffet in People with Obesity, before and 24 Months after Roux-en-Y-Gastric Bypass Surgery

Long-term reductions in the quantity of food consumed, and a shift in intake away from energy dense foods have both been implicated in the potent bariatric effects of Roux-en-Y gastric bypass (RYGB) surgery. We hypothesised that relative to pre-operative assessment, a stereotypical shift to lower intake would be observed at a personalised ad libitum buffet meal 24 months after RYGB, driven in part by decreased selection of high energy density items. At pre-operative baseline, participants (n = 14) rated their preference for 72 individual food items, each of these mapping to one of six categories encompassing high and low-fat choices in combination with sugar, complex carbohydrate or and protein. An 18-item buffet meal was created for each participant based on expressed preferences. Overall energy intake was reduced on average by 60% at the 24-month buffet meal. Reductions in intake were seen across all six food categories. Decreases in the overall intake of all individual macronutrient groups were marked and were generally proportional to reductions in total caloric intake. Patterns of preference and intake, both at baseline and at follow-up appear more idiosyncratic than has been previously suggested by verbal reporting. The data emphasise the consistency with which reductions in ad libitum food intake occur as a sequel of RYGB, this being maintained in the setting of a self-selected ad libitum buffet meal. Exploratory analysis of the data also supports prior reports of a possible relative increase in the proportional intake of protein after RYGB.

Meal Patterns and Food Choices of Female Rats Fed a Cafeteria-Style Diet Are Altered by Gastric Bypass Surgery

After Roux-en-Y gastric bypass surgery (RYGB), rats tend to reduce consumption of high-sugar and/or high-fat foods over time. Here, we sought to investigate the behavioral mechanisms underlying these intake outcomes. Adult female rats were provided a cafeteria diet comprised of five palatable foodstuffs varying in sugar and fat content and intake was monitored continuously. Rats were then assigned to either RYGB, or one of two control (CTL) groups: sham surgery or a nonsurgical control group receiving the same prophylactic iron treatments as RYGB rats. Post-sur-gically, all rats consumed a large first meal of the cafeteria diet. After the first meal, RYGB rats reduced intake primarily by decreasing the meal sizes relative to CTL rats, ate meals more slowly, and displayed altered nycthemeral timing of intake yielding more daytime meals and fewer nighttime meals. Collectively, these meal patterns indicate that despite being motivated to consume a cafeteria diet after RYGB, rats rapidly learn to modify eating behaviors to consume foods more slowly across the entire day. RYGB rats also altered food preferences, but more slowly than the changes in meal patterns, and ate proportionally more energy from complex carbohydrates and protein and proportionally less fat. Overall, the pattern of results suggests that after RYGB rats quickly learn to adjust their size, eating rate, and distribution of meals without altering meal number and to shift their macronutrient intake away from fat; these changes appear to be more related to postingestive events than to a fundamental decline in the palatability of food choices.

Does FGF21 Mediate the Potential Decrease in Sweet Food Intake and Preference Following Bariatric Surgery?

The liver-derived hormone fibroblast growth factor 21 (FGF21) has recently been linked to preference for sweet-tasting food. We hypothesized, that surgery-induced changes in FGF21 could mediate the reduction in sweet food intake and preference following bariatric surgery. Forty participants (35 females) with severe obesity (BMI ≥ 35 kg/m²) scheduled for roux-en-y gastric bypass (n = 30) or sleeve gastrectomy (n = 10) were included. Pre- and postprandial responses of intact plasma FGF21 as well as intake of sweet-tasting food assessed at a buffet meal test, the hedonic evaluation of sweet taste assessed using an apple juice with added sucrose and visual analog scales, and sweet taste sensitivity were assessed before and 6 months after bariatric surgery. In a cross-sectional analysis pre-surgery, pre- and postprandial intact FGF21 levels were negatively associated with the hedonic evaluation of a high-sucrose juice sample (p = 0.03 and p = 0.02). However, no changes in pre- (p = 0.24) or postprandial intact FGF21 levels were found 6 months after surgery (p = 0.11), and individual pre- to postoperative changes in pre- and postprandial intact FGF21 levels were not found to be associated with changes in intake of sweet foods, the hedonic evaluation of sweet taste or sweet taste sensitivity (all p ≥ 0.10). In conclusion, we were not able to show an effect of bariatric surgery on circulating FGF21, and individual postoperative changes in FGF21 were not found to mediate an effect of surgery on sweet food intake and preference.

Evaluation of Dietary Assessment Tools Used in Bariatric Population

Severe obesity is associated with major health issues and bariatric surgery is still the only treatment to offer significant and durable weight loss. Assessment of dietary intakes is an important component of the bariatric surgery process. Objective: To document the dietary assessment tools that have been used with patients targeted for bariatric surgery and patients who had bariatric surgery and explore the extent to which these tools have been validated. Methods: A literature search was conducted to identify studies that used a dietary assessment tool with patients targeted for bariatric surgery or who had bariatric surgery. Results: 108 studies were included. Among all studies included, 27 used a dietary assessment tool that had been validated either as part of the study per se (n = 11) or in a previous study (n = 16). Every tool validated per se in the cited studies was validated among a bariatric population, while none of the tools validated in previous studies were validated in this population. Conclusion: Few studies in bariatric populations used a dietary assessment tool that had been validated in this population. Additional studies are needed to develop valid and robust dietary assessment tools to improve the quality of nutritional studies among bariatric patients.

Methodological issues in assessing change in dietary intake and appetite following gastric bypass surgery: A systematic review

Gastric bypass surgery is an effective long-term treatment for individuals with severe obesity. Changes in appetite, dietary intake, and food preferences have all been postulated to contribute to postoperative body weight regulation, however, findings are inconsistent. The aim of this systematic review was to evaluate the current literature on changes in dietary intake and appetite following gastric bypass surgery, in the context of the methodology used and the analysis, interpretation, and presentation of results. Four databases were systematically searched with terms related to "gastric bypass surgery," "appetite," and "dietary intake," and 49 papers (n = 2384 patients after gastric bypass) were eligible for inclusion. The evidence indicated that only a reduction in overall energy intake and an increase in postprandial satiety are maintained beyond 6-month post-surgery, whereas relative macronutrient intake and premeal hunger remain unchanged. However, available data were limited by inconsistencies in the methods, analysis, presentation, and interpretation of results. In particular, there was a reliance on data collected by subjective methods with minimal acknowledgment of the limitations, such as misreporting of food intake. There is a need for further work employing objective measurement of appetite and dietary intake following gastric bypass surgery to determine how these mechanisms may contribute to weight regulation in the longer term.

The Relationship Between Bariatric Surgery and Diet Quality: a Systematic Review

BACKGROUND

Bariatric surgery is currently the most effective treatment for morbid obesity. These procedures change the gastrointestinal system with the aim of reducing dietary intake. Improving diet quality is essential in maintaining nutritional health and achieving long-term benefits from the surgery. The aim of this systematic review was to examine the relationship between bariatric surgery and diet quality at least 1 year after surgery.

METHODS

A systematic search of five databases was conducted. Studies were included that reported diet quality, eating pattern, or quality of eating in adult patients who had undergone laparoscopic-adjusted gastric banding (LAGB), Roux-en-Y gastric bypass (RYGB), and sleeve gastrectomy (SG) procedures. Data was extracted to determine the relationship between having had bariatric surgery and subsequent diet quality.

RESULTS

A total of 34 study articles (described in 36 articles) met the inclusion criteria. The majority of studies were observational in nature and showed a reduction in energy intake following surgery, as well as inadequate intakes of micronutrients and protein, and an excessive intake of fats. There was evidence of nutrient imbalances, suboptimal compliance with multivitamin and mineral supplementation, and limited follow-up of patients.

CONCLUSION

The current evidence base suggests that despite being effective in reducing energy intake, bariatric surgery can result in unbalanced diets, inadequate micronutrient and protein intakes, and excessive intakes of fats. In combination with suboptimal adherence to multivitamin and mineral supplementation, this may contribute to nutritional deficiencies and weight regain. There is a need for high-quality nutrition studies, to identify optimal dietary compositions following bariatric surgery.

Factors Associated with Favorable Changes in Food Preferences After Bariatric Surgery

PURPOSE

Bariatric surgery may shift food preferences towards less energy-dense foods. Eating behavior is multifactorial, and the mechanisms driving changes in food preferences could be a combination of a physiological response to surgery and social and psychological factors. This exploratory study aimed to identify potential factors explaining the variation in changes in food preferences after bariatric surgery.

MATERIALS AND METHODS

Physiological, social, and psychological data were collected before, 6 weeks or 6 months after surgery. All variables were analyzed in combination using LASSO regression to explain the variation in changes in energy density at an ad libitum buffet meal 6 months after bariatric surgery (n=39).

RESULTS

The following factors explained 69% of the variation in changes in food preferences after surgery and were associated with more favorable changes in food preferences (i.e., a larger decrease in energy density): female gender, increased secretion of glicentin, a larger decrease in the hedonic rating of sweet and fat and a fatty cocoa drink, a lower number of recent life crises, a low degree of social eating pressure, fulfilling the diagnostic criteria for binge eating disorder, less effort needed to obtain preoperative weight loss, a smaller household composition, a lower degree of self-efficacy and a higher degree of depression, nutritional regime competence, and psychosocial risk level.

CONCLUSION

Factors explaining the variation in altered food preferences after bariatric surgery not only include a physiological response to surgery but also social and psychological factors.

The Phantom Satiation Hypothesis of Bariatric Surgery

The excitation of vagal mechanoreceptors located in the stomach wall directly contributes to satiation. Thus, a loss of gastric innervation would normally be expected to result in abrogated satiation, hyperphagia, and unwanted weight gain. While Roux-en-Y-gastric bypass (RYGB) inevitably results in gastric denervation, paradoxically, bypassed subjects continue to experience satiation. Inspired by the literature in neurology on phantom limbs, I propose a new hypothesis in which damage to the stomach innervation during RYGB, including its vagal supply, leads to large-scale maladaptive changes in viscerosensory nerves and connected brain circuits. As a result, satiation may continue to arise, sometimes at exaggerated levels, even in subjects with a denervated or truncated stomach. The same maladaptive changes may also contribute to dysautonomia, unexplained pain, and new emotional responses to eating. I further revisit the metabolic benefits of bariatric surgery, with an emphasis on RYGB, in the light of this phantom satiation hypothesis.

Dietary macro- and micro-nutrients intake adequacy at 6th and 12th month post-bariatric surgery

BACKGROUND

Bariatric surgery (BS) is considered as an effective solution to control morbid obesity. Food restrictions resulting from the operation may decrease dietary nutrient intakes, particularly during the first year after BS. This study mainly aimed to assess the adequacy of dietary nutrient intakes at 6th and 12th month after BS.

METHOD

Of the severely obese participants in the Tehran obesity treatment study in 2015-2016, 58 patients undergoing Roux-En-Y gastric bypass (N = 16) or sleeve gastrectomy (N = 42) were selected from Tehran Obesity Treatment Center. To assess the patients' dietary intake, a three-day, 24-h dietary recall was obtained on three unscheduled days (two non-consecutive weekdays and one weekend day) at 6th and 12th month after BS. To evaluate the adequacy of nutrient intake, the patients' intakes were compared to the current dietary reference intakes (DRIs), including estimated average requirements (EAR) or Adequate Intakes (AI).

RESULTS

The mean age of the participants (71% women) undergoing BS was 37 ± 8 years. Anthropometric parameters significantly decreased at the 12th month after BS. The percentage of energy from carbohydrate intake increased significantly between the 6th and 12th month after BS (P = 0.04). The mean ± SD of protein intake was lower than the recommended dosage with a dramatic decrease from 45 ± 30 to 31 ± 15 (g/day) between the two intervals (P = 0.001). The mean intake of saturated fatty acid (SFA) decreased dramatically (P < 0.001) from 6 to 12 month; however, the median intake of n3-polyunsaturated fatty acid (n3-PUFA) intake increased (P = 0.02). None of the participants showed nutrient intake adequacy in terms of biotin, fat soluble vitamins, pantothenic acid, potassium, and zinc. Moreover, less than 10% of the participants showed nutrient intake adequacy in terms of folate, magnesium, manganese, and calcium according to DRIs during the both intervals after BS.

CONCLUSION

Bariatric surgery can reduce dietary intakes, which is more obvious 12 months after the surgery. Out of 21 micronutrients, nearly all could not met the EAR and were received < 50%, also had significant reduction from the 6th to12th month after surgery.

Changes in bone mass and body composition after bariatric surgery

Aim: To analyze the effects of body weight loss on bone mineral density (BMD) on hip (Hip BMD) and lumbar spine (Lumbar BMD) after six months of bariatric surgery. Bariatric surgery is an effective treatment for morbid obesity. Nonetheless, there are scant data on the effect of weight bearing on bone structure.Material and methods: Seventeen obese women aged 41.2 ± 11.3 yrs. who underwent Roux-en-Y gastric bypass (RYGB) were included. Body composition assessments were performed through dual-energy X-ray absorptiometry immediately before and after 6-months RYGB. Data collected pre- and post-RYGB included total body weight, body mass index (BMI), lean body mass (LM), fat mass (FM) and bone mineral content. The pre- (PRE) and post-operative (POST) results were compared.Results: Lumbar BMD POST presented a non-significant loss of 1.8% whereas Hip BMD POST showed a significant loss of 17.8%. The analysis demonstrated that BMI and LM PRE explained 26% and 49%, respectively, of Hip BMD PRE variability. In addition, LM POST explained 30% of hip BMD POST variability and was not significant for Lumbar BMD POST.Conclusions: Obesity and rapid weight loss showed direct influence in Hip BMD after six months of bariatric surgery. However, its effect on the lumbar spine area was smaller due to the higher capacity of the spine to dissipate loads through its curvature.

Nutrition, Physical Activity, and Prescription of Supplements in Pre- and Post-bariatric Surgery Patients: a Practical Guideline

According to ASMBS, the rate of bariatric surgery increased from 158,000 in 2011 to 196,000 in 2015. Nevertheless, this growth in invasive techniques does not eliminate unhealthy habits, so lifestyle modification such as healthy nutrition and correct physical activity programs may improve surgical results. The objective of the present narrative review was to categorize the guidelines related to nutrition, physical activity, and supplement prescription before and after bariatric surgery. The main key words including nutrition, diet, physical activity, exercise, supplements, macronutrients, micronutrients, weight reduction, bariatric surgery, Roux-en-Y gastric bypass, sleeve gastrostomy, laparoscopic adjustable gastric banding, and biliopancreatic diversion with duodenal switch were searched in databases including PubMed/Medline, Cochrane, and some other sources such as Google scholar. The recommendations are classified based on the type of surgery. The indications for surgery and the type of bariatric surgery are not included in this review. This review helps medical teams, including bariatric surgeons, nutritionists, and sports medicine specialists, with proper management before and after bariatric surgery.

Increase in Protein Intake After 3 Months of RYGB Is an Independent Predictor for the Remission of Obesity in the First Year of Surgery

INTRODUCTION

Although bariatric surgery promotes dietary changes, many questions regarding their effect on weight loss remain unanswered.

OBJECTIVE

The aim of this study was to evaluate changes in dietary intake and predictive factors of obesity remission in the first 12 months after RYGB.

METHODS

Fifty-one patients (mean 39.34 ± 9.38 years, 68.7% women) who underwent RYGB were included in this study. Dietary intake was evaluated through a 24-h dietary recall and subsequently classified by NOVA, macronutrients and calories. The predictive factors for obesity remission within 12 months after RYGB were evaluated by Cox regression.

RESULTS

At baseline, 62.7% of the patients presented severe obesity; mean excess weight loss was greater than 80% after 1 year of surgery and about 70% of the patients were no longer diagnosed with obesity. An increase in percentage of calories from protein was observed at 3 and 12 months after surgery. The caloric contribution of ultra-processed foods was low at 3 months after surgery while that of unprocessed or minimally processed foods was high at 3 and 12 months after surgery. From the Cox regression analysis, preoperative BMI (HR, 0.78; 95% CI, 0.69-0.88) and age (HR, 0.94; 95% CI, 0.89-0.99) showed an inverse association with obesity remission. Also, Δ protein (at 3 months-baseline) showed a positive association with obesity remission (HR, 1.06; 95% CI, 1.01-1.12).

CONCLUSION

Lower preoperative BMI, lower age, and higher protein intake at 3 months after surgery may favor remission of obesity in up to 12 months compared with baseline.

Bone Metabolism in Adolescents and Adults Undergoing Roux-En-Y Gastric Bypass: a Comparative Study

OBJECTIVE

To compare the bone metabolism of adolescents and adults with obesity before undergoing a Roux-en-Y gastric bypass (RYGB) and 6 and 12 months after the surgery.

MATERIALS AND METHODS

Adolescents (G1) and adults (G2) with obesity assessed before (T0), six (T1), and 12 months after (T2) RYGB. Sun exposure, serum concentrations of 25(OH)D, calcium, phosphorous, magnesium, zinc, alkaline phosphatase, parathyroid hormone (PTH), and bone mineral density (BMD) were evaluated.

RESULTS

Sixty adolescents and 60 adults were assessed. At T0, there was no significant difference between the groups' serum 25(OH)D levels (G1 21.87 + 7.52 ng/mL, G2 21.73 + 7.60 ng/mL, p = 0.94) or sun exposure (G1 17 ± 2.0 min/day, G2 13.2 ± 5.2 min/day, p = 0.85). G1 had high levels of inadequacy of calcium (66.7%), phosphorous (80.0%), and zinc (18.3%) at T0 and had a significant fall in their 25(OH)D (p < 0.01) and magnesium (p < 0.01) levels from T1 to T2. G2 saw a significant lowering of their serum zinc levels from T0 to T1 and T2 (T1 p < 0.01; T2 p < 0.01). In both groups, there was a significant rise in PTH from T1 to T2 (G1 p = 0.04, G2 p = 0.02) and from T0 to T2 (G1 and G2 p < 0.01). In G2, 40.4% of individuals with osteopenia and osteoporosis presented inadequacy of 25(OH)D.

CONCLUSION

RYGB was found to worsen the inadequacy of micronutrients related to bone metabolism and was associated with secondary hyperparathyroidism and low BMD values, especially among the adolescents. The irreversible damaging effects of obesity on bone metabolism can occur in adolescence.

Comparison of Energy and Food Intake Between Gastric Bypass and Sleeve Gastrectomy: a Meta-analysis and Systematic Review

AbstractObesity is a developed nutritional problem, and today, surgery is one of the approaches to cure it. A good understanding of the variations in food intake will be beneficial for sustaining long-term weight loss post-surgery and for improving nutrition care strategies. The purpose of this review was the comparison of the impact of two methods of gastric bypass (GBP) and sleeve gastrectomy (SG) on dietary intake. Databases of PubMed, Embase, Scopus, Google Scholar, and Web of science were used for the literature search up to June 2018. We concluded the studies that measured mean daily energy intake and the percent of macronutrients from total calorie intake of before and after GBP and SG. A total of 18 studies were finally included in the meta-analysis for the effect of bariatric surgery on food intake. Bariatric surgery significantly decreased energy intake by 1050.04 kcal/day (p < 0.001) compared with the baseline values of energy intake. The pooled effect of bariatric surgery on protein intake was 0.82 g/day (p = 0.004) compared with the baseline values. The pooled analysis found no significant impact of bariatric surgery on carbohydrate intake (WMD = 0.56 g/day; p = 0.40) compared with the baseline values. The pooled estimate of effect for bariatric surgery on fat intake was - 1.34 g/day (p = 0.006). This study demonstrates that bariatric surgery might be effective on energy and fat intake; however, there was no effect on carbohydrate intake.

Toward a Medical Gastric Bypass: Chronic Feeding Studies With Liraglutide + PYY3-36 Combination Therapy in Diet-Induced Obese Rats

BACKGROUND

Combination therapies of anorectic gut hormones partially mimic the beneficial effects of bariatric surgery. Thus far, the effects of a combined chronic systemic administration of Glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine 3-36 (PYY_3-36) have not been directly compared to Roux-en-Y gastric bypass (RYGB) in a standardized experimental setting.

METHODS

High-fat diet (HFD)-induced obese male Wistar rats were randomized into six treatment groups: (1) RYGB, (2) sham-operation (shams), (3) liraglutide, (4) PYY_3-36, (5) PYY_3-36+liraglutide (6), saline. Animals were kept on a free choice high- and low-fat diet. Food intake, preference, and body weight were measured daily for 4 weeks. Open field (OP) and elevated plus maze (EPM) tests were performed.

RESULTS

RYGB reduced food intake and achieved sustained weight loss. Combined PYY_3-36+liraglutide treatment led to similar and plateaued weight loss compared to RYGB. Combined PYY_3-36+liraglutide treatment was superior to PYY_3-36 (p ≤ 0.0001) and liraglutide (p ≤ 0.05 or p ≤ 0.01) mono-therapy. PYY_3-36+liraglutide treatment and RYGB also reduced overall food intake and (less pronounced) high-fat preference compared to controls. The animals showed no signs of abnormal behavior in OF or EPM.

CONCLUSIONS

Liraglutide and PYY_3-36 combination therapy vastly mimics reduced food intake, food choice and weight reducing benefits of RYGB.

Proceedings of the 2017 ASPEN Research Workshop-Gastric Bypass: Role of the Gut

The goal of the National Institutes of Health-funded American Society for Parenteral and Enteral Nutrition 2017 research workshop (RW) "Gastric Bypass: Role of the Gut" was to focus on the exciting research evaluating gut-derived signals in modulating outcomes after bariatric surgery. Although gastric bypass surgery has undoubted positive effects, the mechanistic basis of improved outcomes cannot be solely explained by caloric restriction. Emerging data suggest that bile acid metabolic pathways, luminal contents, energy balance, gut mucosal integrity, as well as the gut microbiota are significantly modulated after bariatric surgery and may be responsible for the variable outcomes, each of which was rigorously evaluated. The RW served as a timely and novel academic meeting that brought together clinicians and researchers across the scientific spectrum, fostering a unique venue for interdisciplinary collaboration among investigators. It promoted engaging discussion and evolution of new research hypotheses and ideas, driving the development of novel ameliorative, therapeutic, and nonsurgical interventions targeting obesity and its comorbidities. Importantly, a critical evaluation of the current knowledge regarding gut-modulated signaling after bariatric surgery, potential pitfalls, and lacunae were thoroughly addressed.

Bariatric Surgery Leads to Short-Term Effects on Sweet Taste Sensitivity and Hedonic Evaluation of Fatty Food Stimuli

OBJECTIVE

The aim of this study was to investigate the effect of bariatric surgery on sweet taste sensitivity and the hedonic evaluation of sweet, savory, and fatty food stimuli as well as associations with weight loss and food preferences assessed at a buffet meal test.

METHODS

The detection and recognition threshold for sweet taste and the hedonic rating of sweet, savory, and fatty food stimuli were assessed before and after a preoperative diet-induced weight loss and 6 weeks, 6 months, and 18 months after Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) (n = 29).

RESULTS

The detection threshold for sweet taste decreased after the diet-induced weight loss and 6 weeks after RYGB (both P ≤ 0.03). The hedonic rating of high-fat food stimuli decreased 6 weeks after RYGB and SG (all P ≤ 0.02). Changes in the hedonic rating of high-fat food stimuli were associated with increased preferences for high-fat foods at the buffet meal (P = 0.03) and tended to be associated with weight loss (P = 0.05). No changes were detected for sweet and savory food stimuli.

CONCLUSIONS

RYGB increased sweet taste sensitivity; however, this effect was already seen after the diet-induced weight-loss. RYGB and SG decreased the hedonic evaluation of high-fat food stimuli, but this effect did not translate into decreased preferences for high-fat food.

Nutrition, Physical Activity, and Prescription of Supplements in Pre- and Post-bariatric Surgery Patients: a Practical Guideline

According to ASMBS, the rate of bariatric surgery increased from 158,000 in 2011 to 196,000 in 2015. Nevertheless, this growth in invasive techniques does not eliminate unhealthy habits, so lifestyle modification such as healthy nutrition and correct physical activity programs may improve surgical results. The objective of the present narrative review was to categorize the guidelines related to nutrition, physical activity, and supplement prescription before and after bariatric surgery. The main key words including nutrition, diet, physical activity, exercise, supplements, macronutrients, micronutrients, weight reduction, bariatric surgery, Roux-en-Y gastric bypass, sleeve gastrostomy, laparoscopic adjustable gastric banding, and biliopancreatic diversion with duodenal switch were searched in databases including PubMed/Medline, Cochrane, and some other sources such as Google scholar. The recommendations are classified based on the type of surgery. The indications for surgery and the type of bariatric surgery are not included in this review. This review helps medical teams, including bariatric surgeons, nutritionists, and sports medicine specialists, with proper management before and after bariatric surgery.

Effects of Roux-en-Y Gastric Bypass and Sleeve Gastrectomy on Food Preferences and Potential Mechanisms Involved

PURPOSE OF REVIEW

Bariatric surgery leads to a substantial decrease in energy intake. It is unclear whether this decrease in energy intake is simply due to eating smaller portions of the same food items or a shift in food preference towards less energy-dense foods. This review evaluates the existing literature on changes in food preferences after bariatric surgery and the potential mechanisms involved.

RECENT FINDINGS

Changes in food preferences have been reported; however, the evidence is mainly based on indirect measurements, such as self-reporting. When changes in food preferences are directly assessed, results contradict previous findings, indicating that results based on self-reporting must be interpreted with caution as they do not necessarily reflect actual behaviour. However, it seems that there could be inter-individual differences in the response to surgery. Future studies investigating changes in food preferences should not only focus on direct measured of behaviour but should also consider the heterogeneity of the response after bariatric surgery.

Most of qualitative dietary changes observed one year post-bariatric surgery can be achieved with a preoperative dietary intervention

BACKGROUND AND OBJECTIVES

Bariatric surgery (BS) leads to several changes in nutritional habits that can be attributed to different mechanisms. Some of these changes could be achievable with a preoperative nutritional intervention. The objective was to evaluate dietary modifications during the preoperative and postoperative periods of BS.

METHODS

Prospective observational study of patients who underwent BS between 2010 and 2014 at the Hospital del Mar; 60 consecutive patients were included. Food consumption was measured by a validated food-frequency questionnaire at inclusion in the bariatric surgery program, after preoperative nutritional intervention, and one year after surgery. Generalized estimating equation models were used to assess differences in food group intake during follow up.

RESULTS

Energy intake significantly decreased from inclusion to 1 year of surgery (p=0.003). After the preoperative intervention and prior to surgery, there was an increase in intake of nuts, vegetables, poultry and rabbit, fruit, fish and skimmed milk products and a decrease in bread, soft drinks and pastry. At one year post-surgery, a continued decrease in the consumption of bread and soft drinks and an increase in nuts was observed (linear non-quadratic trend). Consumption of fruit, pastry, fish and skimmed milk products remained stable showing a linear and quadratic trend. Vegetables and poultry and rabbit increased in the preoperative period and decreased after surgery, showing a quadratic but not linear trend.

CONCLUSIONS

a preoperative nutritional intervention in morbidly obese patients can associate favorable dietary changes that are mostly maintained one year after bariatric surgery.

Changes in bone mineral density and bone metabolism after sleeve gastrectomy: a systematic review and meta-analysis

BACKGROUND

Roux-en-Y gastric bypass surgery adversely affects bone health. The evidence is less well-described for sleeve gastrectomy (SG).

OBJECTIVES

To better characterize bone metabolism changes after SG.

SETTING

Systematic review and meta-analysis.

METHODS

MEDLINE and EMBASE were searched through March 2019 for eligible studies assessing adults with obesity aged 18 years or older that underwent SG. Bone mineral density (BMD), serum calcium, serum phosphate, serum 25-hydroxyvitamin D, serum parathyroid hormone, or serum alkaline phosphatase were reported at baseline and after SG; and a follow-up duration was at least 6 months. Preoperative and postoperative mean of each outcome of interest and corresponding standard deviations were extracted from each study and the mean difference (MD) was calculated. Pooled MD was then calculated by combining MDs of each study using random-effects model.

RESULTS

A total of 22 studies with 1905 patients with obesity that underwent SG were included. There were significant decreases in total hip BMD (pooled MD of -.06 g/cm²; 95% confidence interval -.09 to -.03; I² = 0%) and femoral neck BMD (pooled MD of -.05 g/cm²; 95% confidence interval -.09 to -.02; I² = 0%) after SG. No significant change in lumbar spine BMD was observed. There were significant increases in serum calcium, serum 25-hydroxyvitamin D, and serum phosphate. Serum parathyroid hormone was significantly decreased. Serum alkaline phosphatase was not significantly altered after SG.

CONCLUSIONS

The present study found a decreased BMD among patients with obesity after SG.

Metabolic surgery and iron homeostasis

Iron deficiency and anaemia after metabolic surgery, potentially modifiable nutritional complications, are becoming an increasing cause for concern as prevalence increases with time and there is limited evidence supporting the effectiveness of the current guidelines for prophylactic oral iron supplementation and treatment for deficiency. Abnormalities in iron nutrition predisposing to deficiency are common in severely obese patients, and the low-grade systemic inflammation, also common to these patients, reduces the effectiveness of oral iron supplementation. The surgical procedures result in alterations of foregut anatomy and physiology, which limit iron absorptive capacity and daily food intake. These alterations and the limited effects of oral iron supplementation explain the high prevalence of postoperative iron deficiency and anaemia. This review outlines current mechanisms concerning the pathogenesis of disordered iron nutrition in patients with severe obesity, current gaps in knowledge, and opportunities for quality improvement.

Bariatric Surgery Does Not Affect Food Preferences, but Individual Changes in Food Preferences May Predict Weight Loss

OBJECTIVE

Using an ad libitum buffet meal targeting direct behavior, the authors of the current study previously reported no effect of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) surgery on food preferences 6 months after surgery. The current study investigated changes in food preferences at 18 months after surgery and whether changes in food preferences at 6 months predicted weight loss.

METHODS

Twenty food items separated into the following food categories were served at the buffet meal: high-fat, low-fat, sweet, savory, high-fat savory, high-fat sweet, low-fat savory, and low-fat sweet. Energy intake and intake from each of the food items were registered. Energy intake prior to the meal was standardized.

RESULTS

Thirty-nine subjects completed visits before surgery and 18 months following RYGB (n = 29) and SG (n = 10) surgery. Energy intake decreased 41% (4,470 ± 209 kJ vs. 2,618 ± 209 kJ, P < 0.001), but no change occurred in relative energy intake from any of the food categories (all P ≥ 0.23), energy density (P = 0.20), or macronutrient intake (all P ≥ 0.28). However, changes in high-fat food intake, protein intake, energy intake, and energy density at 6 months predicted weight loss at 18 months (P ≤ 0.02).

CONCLUSIONS

RYGB surgery and SG surgery do not affect food preferences. However, changes in food preferences seem to be predictive of weight loss.

The Effect of Aerobic or Aerobic-Strength Exercise on Body Composition and Functional Capacity in Patients with BMI ≥35 after Bariatric Surgery: a Randomized Control Trial

BACKGROUND

Although previous studies suggested that bariatric surgery is the most effective and sustainable treatment method for morbid obesity in long term, but without changing in lifestyle, maintaining optimal weight loss is almost impossible.

METHODS

Sixty morbid obese patients (BMI ≥ 35) were evaluated before and after 12 weeks of bariatric surgery in order to compare the impact of two different exercise programs on body composition and functional capacity outcomes. Participants were divided into three groups: aerobic (A), aerobic-strength (AS), and control (C) group. Aerobic capacity was assessed with 12-min walk-run test (12MWRT). One-repetition maximum (1RM) test was performed to evaluation upper limb muscle strength. Lower extremity functional capacity was assessed by sit-to-stand test.

RESULTS

Weight, percent body fat (PBF), and fat mass (FM) reduced greater in the trial groups in comparison to the C group (P < 0.05). In the AS group, the reduction of fat-free mass (FFM) was significantly lower than that in the other groups. Mean changes in 12MWRT increased significantly in the intervention groups. The mean change in the sit-to-stand scores was not statistically significant between the three groups. Comparing the intervention groups showed that mean changes in 1RM variables increased in AS group (P = 0.03).

CONCLUSIONS

The data suggests a positive effect of exercise on weight and PBF decrease after surgery, and it leads to significant improvement on aerobic capacity. Moreover, doing resisted exercise caused greater preserving of lean mass.

Iron deficiency after bariatric surgery: what is the real problem?

The growing prevalence of obesity explains the rising interest in bariatric surgery. Compared with non-surgical treatment options, bariatric surgery results in greater and sustained improvements in weight loss, obesity associated complications, all-cause mortality and quality of life. These encouraging metabolic and weight effects come with a downside, namely the risk of nutritional deficiencies. Particularly striking is the risk to develop iron deficiency. Postoperatively, the prevalence of iron deficiency varies between 18 and 53 % after Roux-en-Y gastric bypass and between 1 and 54 % after sleeve gastrectomy. Therefore, preventive strategies and effective treatment options for iron deficiency are crucial to successfully manage the iron status of patients after bariatric surgery. With this review, we discuss the risks and the contributing factors of developing iron deficiency after bariatric surgery. Furthermore, we highlight the discrepancy in the diagnosis of iron deficiency, iron deficiency anaemia and anaemia and highlight the evidence supporting the current nutritional recommendations in the field of bariatric research. In conclusion, we advocate for more nutrition-related research in patient populations in order to provide strong evidence-based guidelines after bariatric surgery.

Mechanisms of weight loss and improved metabolism following bariatric surgery

Bariatric surgery is increasingly recognized as one of the most effective interventions to help patients achieve significant and sustained weight loss, as well as improved metabolic and overall health. Unfortunately, the cellular and physiological mechanisms by which bariatric surgery achieves weight loss have not been fully elucidated, yet are critical to understanding the central role of the intestinal tract in whole-body metabolism and to developing novel strategies for the treatment of obesity. In this review, we provide an overview of potential mechanisms contributing to weight loss, including effects on regulation of energy balance and both central and peripheral nervous system regulation of appetite and metabolism. Moreover, we highlight the importance of the gastrointestinal tract, including alterations in bile acid physiology, secretion of intestinally derived hormones, and the microbiome, as a potent mediator of improved metabolism in postbariatric patients.

Perspectives in obesity and pregnancy

Obesity is currently recognized as a health epidemic worldwide. Its prevalence has doubled in the last three decades. Obesity is a complex clinical picture associated with physical, physiologic, hormonal, genetic, cultural, socioeconomic and environmental factors. The rate of obesity is also increasing in the pregnant women population. Maternal obesity is associated with less than optimal obstetrical, fetal and neonatal outcomes. It is also associated with significant adverse long-term effects on both obese parturients and the infants born from obese women. A number of guidelines have been published to educate health care workers and the general population in an attempt to develop effective interventions on a large scale to prevent obesity. These guidelines are multiple, confusing and inconsistent. There are no standard recommendations regarding gestational weight gaining goals, nutrients and additional elements necessary for certain obese women who have been treated with bariatric surgical procedures, screening for metabolic diseases such as diabetes, additional preventive health care services indicated for obese women in the pregnancy planning stages, during prenatal care, in the immediate post-partum period and as a long-term approach for health preservation. In 2013, the American Medical Association supported by several US national medical specialty organizations published Resolution 420 (A-13) recognizing obesity as a disease state with multiple pathophysiological aspects requiring a range of interventions to improve its prevention and treatment. The goal of this decision was to encourage a broader spectrum of health care benefits insurance coverage for the prevention and treatment of obesity. There are a number of myths and misconceptions associated with obesity. These perspectives present our views and clinical experience with a partial review of recent bibliography addressing the associations between obese reproductive age women and their risks during pregnancy.

Micronutrient intake, from diet and supplements, and association with status markers in pre- and post-RYGB patients

BACKGROUND & AIMS

Roux-en-Y gastric bypass (RYGB) is associated with an increased risk for micronutrient deficiencies. This study aimed to assess total (dietary and supplement) intake and association with iron (including hepcidin), vitamin B₁₂, vitamin C and zinc status markers before and after Roux-en-Y gastric bypass (RYGB).

METHODS

This prospective study included patients with a planned RYGB in University Hospitals Leuven, Belgium; who were followed until 12 months post-RYGB. Patients completed an estimated dietary record of two non-consecutive days before and 1, 3, 6 and 12 months post-RYGB and supplement/drug use was registered. Associations between total micronutrient intake and status markers were analyzed.

RESULTS

Fifty-four patients (21 males; mean age: 48.0 [95%CI 46.6; 49.3] years; mean preoperative BMI: 40.4 [95%CI 39.4; 41.4] kg/m²) were included. One month post-RYGB, usual dietary intake of the studied micronutrients was significantly decreased compared to pre-RYGB, but gradually increased until 12 months post-RYGB, remaining below baseline values. By including micronutrient supplement intake, 12 months post-RYGB values were higher than baseline, except for zinc. Hemoglobin, ferritin, vitamin B₁₂ and C-reactive protein serum concentrations were significantly decreased and transferrin saturation and mean corpuscular volume were significantly increased 12 months post-RYGB. Serum hepcidin concentration was significantly decreased 6 months post-RYGB.

CONCLUSIONS

Medical nutritional therapy is essential following RYGB as dietary intake of iron, vitamin B₁₂, vitamin C, copper and zinc was markedly decreased postoperatively and some patients still had an inadequate total intake one year post-RYGB.

Mechanism Underlying the Weight Loss and Complications of Roux-en-Y Gastric Bypass. Review

Various bariatric surgical procedures are effective at improving health in patients with obesity associated co-morbidities, but the aim of this review is to specifically describe the mechanisms through which Roux-en-Y gastric bypass (RYGB) surgery enables weight loss for obese patients using observations from both human and animal studies. Perhaps most but not all clinicians would agree that the beneficial effects outweigh the harm of RYGB; however, the mechanisms for both the beneficial and deleterious (for example postprandial hypoglycaemia, vitamin deficiency and bone loss) effects are ill understood. The exaggerated release of the satiety gut hormones, such as GLP-1 and PYY, with their central and peripheral effects on food intake has given new insight into the physiological changes that happen after surgery. The initial enthusiasm after the discovery of the role of the gut hormones following RYGB may need to be tempered as the magnitude of the effects of these hormonal responses on weight loss may have been overestimated. The physiological changes after RYGB are unlikely to be due to a single hormone, or single mechanism, but most likely involve complex gut-brain signalling. Understanding the mechanisms involved with the beneficial and deleterious effects of RYGB will speed up the development of effective, cheaper and safer surgical and non-surgical treatments for obesity.

Energy and macronutrient intake after gastric bypass for morbid obesity: a 3-y observational study focused on protein consumption

BACKGROUND

The effect of a Roux-en-Y gastric bypass (RYGB) on body weight has been amply documented, but few studies have simultaneously assessed the evolution of energy and macronutrient intakes, energy expenditure, and changes in body composition over time after an RYGB.

OBJECTIVE

We evaluated energy and macronutrient intakes, body composition, and the basal metabolic rate (BMR) in obese female patients during the initial 3 y after an RYGB.

METHODS

Sixteen women with a mean ± SEM body mass index (in kg/m(2)) of 44.1 ± 1.6 were included in this prospective observational study. The women were studied on 6 different occasions as follows: before and 1, 3, 6, 12 (n = 16), and 36 (n = 8) mo after surgery. On each occasion, food intake was evaluated from 4- or 7-d dietary records, body composition was assessed with the use of bio-impedancemetry, and energy expenditure was measured with the use of indirect calorimetry.

RESULTS

Body weight evolution showed the typical pattern reported after an RYGB. Total energy intake was 2072 ± 108 kcal/d at baseline and decreased to 681 ± 58 kcal/d at 1 mo after surgery (P < 0.05 compared with at baseline). Total energy intake progressively increased to reach 1240 ± 87 kcal/d at 12 mo after surgery (P < 0.05 compared with at 1 mo after surgery) and 1448 ± 57 kcal/d at 36 mo after surgery (P < 0.05 compared with at 12 mo after surgery). Protein intake was 87 ± 4 g/d at baseline and ± 2 g/d 1 mo after surgery (P < 0.05 compared with at baseline) and increased progressively thereafter to reach 57 ± 3 g/d at 36 mo after surgery (P < 0.05 compared with at 1 mo after surgery). Carbohydrate and fat intakes over time showed similar patterns. Protein intake from meat and cheese were significantly reduced early at 1 mo after surgery but increased thereafter (P < 0.05). The BMR decreased from 1.12 ± 0.04 kcal/min at baseline to 0.93 ± 0.03, 0.86 ± 0.03, and 0.85 ± 0.04 kcal/min at 3, 12, and 36 mo after surgery, respectively (all P < 0.05 compared with at baseline).

CONCLUSIONS

Total energy, carbohydrate, fat, and protein intakes decreased markedly during the initial 1-3 mo after an RYGB, whereas the BMR moderately decreased. The reduction in protein intake was particularly severe at 1 mo after surgery, and protein intake increased gradually after 3-6 mo after surgery. This trial was registered at clinicaltrials.gov as NCT01891591.

"When the honeymoon is over, the real work begins:" Gastric bypass patients' weight loss trajectories and dietary change experiences

To understand gastric bypass patients' experiences with managing food and eating for long-term weight management, this study examined patients' self-reported dietary changes and weight loss patterns. Thirteen women and three men between 15 months and 10 years post-gastric bypass surgery were recruited in Upstate New York. They completed two qualitative, in-depth interviews about their weight loss and dietary experiences. Using verbatim transcripts, researchers created timelines for each participant that summarized weight changes and the associated dietary behaviors. Constant comparative analysis of the timelines and transcripts identified a common, initial rapid weight loss period followed by weight stabilization, after which participants' weight loss patterns diverged into three possible long-term trajectories (Maintaining, Regained/Losing, and Regained) and one short-term trajectory (Losing). Dietary management over the periods of weight loss involved six components: physical needs, hunger and fullness, relationship with food, strategy use, habit formation, and awareness of eating. In the "honeymoon period" weight loss was "easy" because "surgery does the work" in limiting appetite, portion sizes, and interest in foods. As weight stabilized, "the work begins" as participants became capable of eating a greater quantity and a wider variety of foods. Differences in weight loss trajectories were associated with participants' abilities to maintain changes in relationship with food, dietary strategies and habits, and awareness of eating behaviors. Viewing weight loss outcomes of gastric bypass surgery as trajectories that develop as the result of dietary transitions and changes in dietary management suggests that patients need to be counseled on a variety of cognitive and behavioral strategies.

An optimized multivitamin supplement lowers the number of vitamin and mineral deficiencies three years after Roux-en-Y gastric bypass: a cohort study

BACKGROUND

Vitamin and mineral deficiencies are common after Roux-en-Y gastric bypass (RYGB) surgery. In particular, inadequate serum concentrations of ferritin and vitamin B12 have been found in 11% and 23% (respectively) of patients using a standard multivitamin supplement (sMVS) 1 year after RYGB.

OBJECTIVE

To evaluate the effectiveness and safety of Weight Loss Surgery (WLS) Forte® (a pharmaceutical-grade, optimized multivitamin supplement) compared with an sMVS and a control group (nonuser) 3 years after RYGB.

SETTING

General hospital specialized in bariatric surgery.

METHODS

A follow-up cohort study of a triple-blind randomized, controlled clinical trial.

RESULTS

At baseline 148 patients were enrolled (74 [50%] in the sMVS group and 74 [50%] in the WLS Forte group). After a mean follow-up of 36 months, 11 (7%) patients were lost to follow-up, of whom 2 were secondary to death. At the end of the study, 11 (17%) patients in the WLS Forte and 17 (24%) in the sMVS group stopped using a supplement. In addition, 64 (47%) patients were using WLS Forte and 45 (33%) patients a sMVS. Patient characteristics and follow-up length were comparable between the groups. Significantly more patients were diagnosed with anemia (16% versus 3% [P = .021]), a ferritin deficiency (14% versus 3% [P = .043]), and a zinc deficiency (8% versus 0% [P = .033]) in the sMVS group compared with WLS Forte. Five patients developed a vitamin B12 deficiency while using WLS Forte, versus 15 of sMVS users (P = .001). No adverse events occurred that were related to supplement use.

CONCLUSION

At 3 years postoperative of RYGB, an optimized multivitamin supplement (WLS Forte) was more effective in reducing anemia and ferritin, vitamin B12, and zinc deficiencies compared with a standard supplement and control.