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

Tackling the dual burden of malnutrition in pregnancy - pregnancy after weight loss surgery

The dual burden of malnutrition is characterised by the coexistence of undernutrition alongside overweight/obesity and diet-related noncommunicable diseases. It is a paradox which disproportionately affects women and is applicable to those who become pregnant after weight loss surgery. Obesity before and during pregnancy is associated with increased risk of adverse perinatal outcomes in both mother and child. Overall lifestyle interventions targeting weight loss in the preconception period have not proven effective, with people, and women in particular, increasingly seeking weight loss surgery. In women with severe obesity, surgery may normalise hormonal abnormalities and improve fertility. In those who become pregnant after surgery, evidence suggests a better overall obstetric outcome compared to those with severe obesity managed conservatively; however, there is heightened risk of maternal nutritional deficiencies and infants born small for gestational age. Specifically, pregnancy soon after surgery, in the catabolic phase when rapid weight loss is occurring, has the potential for poor outcomes. Lifelong micronutrient supplementation is required, and there is considerable risk of malnutrition if nutritional aftercare guidelines are not adhered to. It is therefore recommended that pregnancy is delayed until a stable weight is achieved and is supported by individualised advice from a multidisciplinary team. Further research is required to better understand how weight loss surgery affects the chances of having a healthy pregnancy and to ultimately improve nutritional management and patient care. In this review, we aim to summarise the evidence and guidance around nutrition during pregnancy after weight loss 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.

Evaluation of nutritional, anthropometric, and psychological outcomes in different metabolic and bariatric surgery techniques: a follow up study

BACKGROUND

Metabolic and bariatric surgery (MBS) is a suitable solution for the treatment of morbid obesity. Investigating an MBS method that has the best outcomes has always been the main concern of physicians. The current study aimed to compare nutritional, anthropometric, and psychological complications of individuals undergoing various MBS Techniques.

METHODS

A total of 96 subjects, who had been already referred to the obesity clinic of Firoozgar Hospital, Tehran, Iran, for MBS, were selected for the study and were followed for one year after MBS. The dietary intakes of the participants were assessed using a Food Frequency Questionnaire (FFQ) on a daily, weekly, monthly, or yearly basis. The mental health of participants was done via the Symptom Checklist 90 Revised. Furthermore, the In-Body 720 bioelectrical impedance device was used to obtain the body composition of the participants at the beginning and the end of the study.

RESULTS

The mean age of the participants was 39.5 ± 9.5 years. All anthropometric indices including weight, Body Mass Index (BMI), protein content, fat mass, and fat mass percentage decreased after Roux-en-Y gastric bypass (RYGB), one-anastomosis gastric bypass (OAGB), and sleeve gastrectomy (SG) surgeries (P < 0.05). After adjustments for confounders, no significant difference was observed in the magnitude of the changes in body composition between the three Techniques (p > 0.05). Energy and carbohydrate intake significantly decreased after surgeries in all three groups (p < 0.05), but comparing the methods no significant difference was revealed (p > 0.05). Furthermore, the results indicated that there was a significant relationship between the mental health of patients before and after surgeries (p < 0.05).

CONCLUSION

Overall, all three methods of surgery contributed to the improvement of the nutritional, anthropometric, and psychological complications. Further complementary studies are needed to determine the least complicated MBS method.

Weight Regain after Metabolic Surgery: Beyond the Surgical Failure

Patients undergoing metabolic surgery have factors ranging from anatomo-surgical, endocrine metabolic, eating patterns and physical activity, mental health and psychological factors. Some of the latter can explain the possible pathophysiological neuroendocrine, metabolic, and adaptive mechanisms that cause the high prevalence of weight regain in postbariatric patients. Even metabolic surgery has proven to be effective in reducing excess weight in patients with obesity; some of them regain weight after this intervention. In this vein, several studies have been conducted to search factors and mechanisms involved in weight regain, to stablish strategies to manage this complication by combining metabolic surgery with either lifestyle changes, behavioral therapies, pharmacotherapy, endoscopic interventions, or finally, surgical revision. The aim of this revision is to describe certain aspects and mechanisms behind weight regain after metabolic surgery, along with preventive and therapeutic strategies for this complication.

Obesity surgery and neural correlates of human eating behaviour: A systematic review of functional MRI studies

Changes in eating behaviour including reductions in appetite and food intake, and healthier food cue reactivity, reward, hedonics and potentially also preference, contribute to weight loss and its health benefits after obesity surgery. Functional magnetic resonance imaging (fMRI) has been increasingly used to interrogate the neural correlates of eating behaviour in obesity, including brain reward-cognitive systems, changes after obesity surgery, and links with alterations in the gut-hormone-brain axis. Neural responses to food cues can be measured by changes in blood oxygen level dependent (BOLD) signal in brain regions involved in reward processing, including caudate, putamen, nucleus accumbens, insula, amygdala, orbitofrontal cortex, and top-down inhibitory control, including dorsolateral prefrontal cortex (dlPFC). This systematic review aimed to examine: (i) results of human fMRI studies involving obesity surgery, (ii) important methodological differences in study design across studies, and (iii) correlations and associations of fMRI findings with clinical outcomes, other eating behaviour measures and mechanistic measures. Of 741 articles identified, 23 were eligible for inclusion: 16 (69.6%) longitudinal, two (8.7%) predictive, and five (21.7%) cross-sectional studies. Seventeen studies (77.3%) included patients having Roux-en-Y gastric bypass (RYGB) surgery, six (26.1%) vertical sleeve gastrectomy (VSG), and five (21.7%) laparoscopic adjustable gastric banding (LAGB). The majority of studies (86.0%) were identified as having a very low risk of bias, though only six (27.3%) were controlled interventional studies, with none including randomisation to surgical and control interventions. The remaining studies (14.0%) had a low risk of bias driven by their control groups not having an active treatment. After RYGB surgery, food cue reactivity often decreased or was unchanged in brain reward systems, and there were inconsistent findings as to whether reductions in food cue reactivity was greater for high-energy than low-energy foods. There was minimal evidence from studies of VSG and LAGB surgeries for changes in food cue reactivity in brain reward systems, though effects of VSG surgery on food cue reactivity in the dlPFC were more consistently found. There was consistent evidence for post-operative increases in satiety gut hormones glucagon-like-peptide 1 (GLP-1) and peptide YY (PYY) mediating reduced food cue reactivity after RYGB surgery, including two interventional studies. Methodological heterogeneity across studies, including nutritional state, nature of food cues, post-operative timing, lack of control groups for order effects and weight loss or dietary/psychological advice, and often small sample sizes, limited the conclusions that could be drawn, especially for correlational analyses with clinical outcomes, other eating behaviour measures and potential mediators. This systematic review provides a detailed data resource for those performing or analysing fMRI studies of obesity surgery and makes suggestions to help improve reporting and design of such studies, as well as future directions.

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.

Testing for Protein Leverage in Patients with Gastric Bypass: A Pilot Study

INTRODUCTION

Protein leverage (PL) is the phenomenon whereby a dominant appetite for protein drives overconsumption of energy with a decline in the ratio of protein to fat and carbohydrate in the diet. PL has been independently verified in several randomized control trials, and its predictions are supported by diet surveillance data. Our aim in the present study was to test whether surgical intervention through gastric bypass will ameliorate the PL effect.

METHODS

Ten patients with gastric bypass (2-5 years postsurgical time) were given ad libitum access to study food comprising 10%, 15%, or 25% protein and no access to other foods for 3 days while controlling food palatability and variety. Food intake was measured, and energy and nutrient intakes were calculated. Body weight, blood chemistry, lipid profile, hormones (insulin, leptin, and ghrelin), and creatinine were determined before and after each experimental period.

RESULTS

The gastric bypass patients in our study did not show evidence for protein intake regulation as predicted under PL but ate to constant total energy intake on the 10%, 15%, and 25% protein diets with protein intake varying significantly. Patients lost weight in the three study periods, but significant weight loss was observed only on the 15% protein diet.

CONCLUSION

Our results suggest that gastric bypass might disengage the PL mechanism, thus ameliorating an appetite-specific mechanism that drives energy overconsumption in modern food environments.

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.

Roux-en-Y gastric bypass, gastric banding, or sleeve gastrectomy for severe obesity: Baseline data from the By-Band-Sleeve randomized controlled trial

OBJECTIVE

This paper reports the study design, participant characteristics, and recruitment results of By-Band-Sleeve, which investigated the clinical and cost-effectiveness of gastric bypass, gastric banding, and sleeve gastrectomy in adults with severe obesity in the UK.

METHODS

A pragmatic open adaptive noninferiority trial with 3-year follow-up was conducted. Participants were randomly assigned to bypass or band initially and to sleeve after the adaptation. Co-primary end points are weight loss and health-related quality of life assessed using the EQ-5D utility index.

RESULTS

Between December 2012 and August 2015, the study recruited into two groups and, after the adaptation, into three groups until September 2019. The study screened 6960 patients; 4732 (68%) were eligible and 1351 (29%) were randomized; 5 subsequently withdrew consent to use data, leaving 462, 464, and 420 assigned to bypass, band, and sleeve, respectively. Baseline data showed high levels of obesity (mean BMI = 46.4 kg/m2; SD: 6.9) and comorbidities (e.g., 31% diabetes), low scores for health-related quality of life, and high levels of anxiety and depression (e.g., 25% abnormal scores). Nutritional parameters were poor, and the average equivalized household income was low (£16,667).

CONCLUSIONS

By-Band-Sleeve fully recruited. Participant characteristics are consistent with contemporary patients having bariatric surgery, and therefore the results will be generalizable.

Food preferences after bariatric surgery: a review update

Obesity is a serious and global health problem. The multiple complications of obesity reduce quality of life and increase mortality. Bariatric surgery is one of the best treatment options for obesity management. Bariatric surgery helps people reduce their caloric intake by treating the disease of obesity effectively, in part by increasing signaling from the gut to the brain. The most frequent surgical options are Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG). There is controversy regarding changes in food preferences and selection after bariatric surgery. In this review, we aim to outline the changes in food intake and selection, clarify the behavior changes in food intake, and assess the potential mechanisms responsible for these changes in patients after bariatric surgery.

The effect of β-caryophyllene on food addiction and its related behaviors: A randomized, double-blind, placebo-controlled trial

Food addiction (FA) is a psychological construct that may be involved in the etiology of obesity. The cannabinoid system is involved in the addictive-like food preferences by acting on the dopaminergic pathway of the brain. β-caryophyllene is a dietary cannabinoid that is a cannabinoid type 2 (CB2) receptor agonist. This study explored the impacts of β-caryophyllene supplementation on eating behavior, appetite, mental health, anthropometric parameters, body composition, and some hormones related to appetite in women with obesity diagnosed with FA. Women with obesity and FA, diagnosed by the Yale Food Addiction Scale Score (YFAS-S) ≥3, were randomly allocated to receive a β-caryophyllene softgel (n = 26) (100 mg/daily with meal) or placebo (n = 26) for 8 weeks. Anthropometric measurements, body composition, eating behavior, biochemical markers, dietary intake, appetite, stress, anxiety, and depression were evaluated during the study period. β-caryophyllene administration significantly reduced YFAS-S compared to the placebo group (changes in FA score: 1.5 ± 0.9 vs. - 0.7 ± 1.4; corrected P = 0.05). Serum levels of orexin-A significantly decreased in the β-caryophyllene group (p = 0.02); however, no significant difference was observed compared to the placebo group (corrected P = 0.09). β-caryophyllene supplementation had no significant effect on body composition, anthropometric indices, appetite, eating behavior, dietary intake, physical activity level, mental health, and levels of oxytocin and neuropeptide Y (NPY), compared to the placebo. β-caryophyllene supplementation may have beneficial effects on improving YFAS-S in women with obesity diagnosed with FA. TRIAL REGISTRATION: Iranian Registry of Clinical Trials identifier: IRCT20200914048712N1.

Meat consumption and the risk of general and central obesity: the Shahedieh study

Objective

This study aimed to investigate the relations of total meat intake and its subtypes, including red and processed meat, white meat, poultry, fish, and organ meat to the risk of general/central obesity.

Methods

This cross-sectional study included a total of 7312 Iranian adults with the age range of 35–70 years from the Shahedieh cohort study, Yazd, Iran. Dietary intake of subjects was evaluated using a validated 120-item Food Frequency Questionnaire. General obesity was defined as body mass index ≥ 30 kg/m2 and central obesity as waist circumference ≥ 102 cm in men and ≥ 88 cm in women.

Results

After controlling for potential covariates including energy intake, age, marital status, gender, physical activity, supplement use, house possession, education, family size, current smoking, night shift working, history of thyroid disease and depression, and intakes of vegetables, legumes, nuts, fruits, whole grains, and dairy, a significant direct association was found between the higher consumption of white meat (OR = 1.31; 95% CI: 1.06–1.61) and poultry (OR = 1.23; 95% CI: 1.04–1.45) with odds of general obesity. Processed meat was a significant predictor for central obesity in the fully adjusted model, so that individuals in the fourth quartile of processed meat intake, compared with those in the first quartile, had a 22% (OR = 1.22; 95% CI: 1.04–1.43) increased risk to be centrally obese.

Conclusion

This study reveals that higher intakes of white meat and poultry are associated with increased risk of general obesity, while, processed meat consumption was associated with central obesity.

Resolution of diabetes, gastrointestinal symptoms, and self-reported dietary intake after gastric bypass vs sleeve gastrectomy – a randomized study

BACKGROUND

There is a lack of randomized studies examining diabetes remission and dietary intake between patients undergoing Roux-en-Y gastric bypass (RYGB) versus sleeve gastrectomy (SG).

OBJECTIVE

To examine longitudinal differences in diabetes resolution, dietary intake, and gastrointestinal (GI) symptoms in patients with obesity and type 2 diabetes (T2D) randomized to either RYGB or SG and according to remission of T2D.

SETTING

Four hospitals in Sweden, 2 of which are university hospitals.

METHODS

Dietary intake and GI symptoms were calculated from questionnaires and morphometric differences between surgical methods and T2D remission were compared using the Student t test, effect size (ES) for parametric parameters, and Mann-Whitney U test for nonparametric parameters.

RESULTS

Five years after RYGB or SG there was no significant difference in the rate of remission of T2D between RYGB and SG (43% versus 20%, P = .176). RYGB (n = 19) patients had greater weight loss than SG patients (n = 14) (26.4 [9.5] versus 13.1 [9.6] kg, P < .001), despite reporting higher daily caloric intake (Δ 669 kcal, P = .059, ES .67) and food weight (Δ 1029 g/d, P = .003, ES 1.11). RYGB patients, compared with SG patients, also ate 1 more fruit per day (P = .023). Pooled data showed no differences between patients with and without T2D remission regarding weight loss, but those in remission drank more nonalcoholic drinks and milk.

CONCLUSIONS

Five years postoperatively, patients randomized to RYGB reported considerably higher food intake compared with SG despite lower body weight. The reason and importance of the higher food intake after RYGB compared with SG needs to be further studied.

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.

Interaction of MC4R rs17782313 variants and dietary carbohydrate quantity and quality on basal metabolic rate and general and central obesity in overweight/obese women: a cross-sectional study

BACKGROUND

Recent studies have shown that dietary carbohydrate quantity and quality as well as genetic variants may contribute to determining the metabolic rate and general and central obesity. This study aimed to examine interactions between melanocortin 4 receptor gene (MC4R) rs17782313 and dietary carbohydrate intake, glycemic index (GI), and glycemic load (GL) on body mass index (BMI), waist circumferences (WC), basal metabolic rate (BMR), and BMR/kg in overweight/obese women.

METHODS

A total of 282 Iranian women (BMI ≥ 25) aged 18-56 years were enrolled in this cross-sectional study. All participants were assessed for blood parameters, body composition, BMR, and dietary intake. Dietary carbohydrate intake, GI, and GL were determined using a valid, reliable 147-item food frequency questionnaire. MC4R rs17782313 was genotyped by the restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

After adjustment for age and energy intake, significant interactions were observed between carbohydrate intake and MC4R rs17782313 in terms of BMI (P Interaction = 0.007), WC (P Interaction = 0.02), and BMR/kg (P Interaction = 0.003) in this way that higher carbohydrate intake, compared with lower intake, was associated with an increase in BMI and WC for individuals with C allele carriers (TC + CC genotypes), while related to an increase in BMR/kg for those carrying the TT genotype. No significant interaction was found between MC4R rs17782313 and GI and GL on BMI, WC, BMR/kg, and BMR.

CONCLUSIONS

Interactions between the MC4R rs17782313 and carbohydrate intake probably can have an effect on BMI, WC, and BMR/kg in overweight/obese women.

Evaluation of the impact of gastric bypass surgery on eating behaviour using objective methodologies under residential conditions: Rationale and study protocol

Gastric bypass surgery leads to significant and sustained weight loss and a reduction in associated health risks in individuals with severe obesity. While reduced energy intake (EI) is the primary driver of weight loss following surgery, the underlying mechanisms accounting for this energy deficit are not well understood. The evidence base has been constrained by a lack of fit-for-purpose methodology in assessing food intake coupled with follow-up studies that are relatively short-term. This paper describes the underlying rationale and protocol for an observational, fully residential study using covert, objective methodology to evaluate changes in 24-hr food intake in patients (n = 31) at 1-month pre-surgery and 3-, 12- and 24-months post-surgery, compared to weight-stable controls (n = 32). The main study endpoints included change in EI, macronutrient intake, food preferences, and eating behaviours (speed, frequency, and duration of eating). Other physiological changes that may influence EI and weight regulation including changes in body composition, circulating appetite hormones, resting metabolic rate, total energy expenditure and gastrointestinal symptoms were also evaluated. Understanding which mechanisms contribute to a reduction in EI and weight loss post-surgery could potentially help to identify those individuals who are most likely to benefit from gastric bypass surgery as well as those that may need more targeted intervention to optimise their weight loss post-surgery. Furthermore, clarification of these mechanisms may also inform targeted approaches for non-surgical treatments of obesity.

Dietary induction of obesity and insulin resistance is associated with changes in Fgf21 DNA methylation in liver of mice

DNA methylation is dynamically regulated in metabolic diseases, but it remains unclear whether the changes are causal or consequential. Therefore, we used a longitudinal approach to refine the onset of metabolic and DNA methylation changes at high temporal resolution. Male C57BL/6N mice were fed with 60 % high-fat diet (HFD) for up to 12 weeks and metabolically characterized weekly. Liver was collected after 1, 2, 4, 5, 6, 7, 8, and 12 weeks and hepatic DNA methylation and gene expression were analyzed. A subset of obese mice underwent vertical sleeve gastrectomy (VSG) or metformin treatment and livers were studied. Distinct hepatic gene expression patterns developed upon feeding HFD, with genes from the fatty acid metabolism pathway being predominantly altered. When comparing metabolic data with gene expression and DNA methylation, in particular Fgf21 DNA methylation decreased before the onset of increased Fgf21 expression and metabolic changes. Neither weight loss induced by VSG nor improved glucose tolerance by metformin treatment could revert hepatic Fgf21 DNA methylation or expression. Our data emphasize the dynamic induction of DNA methylation upon metabolic stimuli. Reduced Fgf21 DNA methylation established before massive overexpression of Fgf21, which is likely an adaptive effort of the liver to maintain glucose homeostasis despite the developing insulin resistance and steatosis. Fgf21 DNA methylation resisted reversion by intervention strategies, illustrating the long-term effects of unhealthy lifestyle. Our data provide a temporal roadmap to the development of hepatic insulin resistance, comprehensively linking DNA methylation with gene expression and metabolic data.

Why We Eat Too Much, Have an Easier Time Gaining Than Losing Weight, and Expend Too Little Energy: Suggestions for Counteracting or Mitigating These Problems

The intent of this review is to survey physiological, psychological, and societal obstacles to the control of eating and body weight maintenance and offer some evidence-based solutions. Physiological obstacles are genetic and therefore not amenable to direct abatement. They include an absence of feedback control against gaining weight; a non-homeostatic relationship between motivations to be physically active and weight gain; dependence of hunger and satiation on the volume of food ingested by mouth and processed by the gastrointestinal tract and not on circulating metabolites and putative hunger or satiation hormones. Further, stomach size increases from overeating and binging, and there is difficulty in maintaining weight reductions due to a decline in resting metabolism, increased hunger, and enhanced efficiency of energy storage. Finally, we bear the evolutionary burden of extraordinary human capacity to store body fat. Of the psychological barriers, human craving for palatable food, tendency to overeat in company of others, and gullibility to overeat when offered large portions, can be overcome consciously. The tendency to eat an unnecessary number of meals during the wakeful period can be mitigated by time-restricted feeding to a 6-10 hour period. Social barriers of replacing individual physical work by labor-saving appliances, designing built environments more suitable for car than active transportation; government food macronutrient advice that increases insulin resistance; overabundance of inexpensive food; and profit-driven efforts by the food industry to market energy-dense and nutritionally compromised food are best overcome by informed individual macronutrient choices and appropriate timing of exercise with respect to meals, both of which can decrease insulin resistance. The best defense against overeating, weight gain, and inactivity is the understanding of factors eliciting them and of strategies that can avoid and mitigate them.

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.

Effect of bariatric surgery on endogenous sex hormones and sex hormone-binding globulin levels: a systematic review and meta-analysis

BACKGROUND

Most studies have shown beneficial effect of bariatric surgery (BS) on serum levels of sex hormones.

OBJECTIVE

A systematic review and meta-analysis was conducted to examine the magnitude of possible changes in levels of sex hormones following BS.

SETTINGS

Electronic databases were searched, including PubMed, Scopus, Web of Science, and Embase, for relevant studies.

METHODS

The heterogeneity of the studies was examined by χ² tests and the degree of heterogeneity was estimated using I² statistic.

RESULTS

The results of pooled analyses revealed that BS caused a significant increase in luteinizing hormone (LH), follicular stimulating hormone (FSH), total testosterone (TT), and sex hormone binding globulin (SHBG) levels and conversely, decreased dehydroepiandrosterone (DHEA) and estradiol (E2) levels in males. For females, BS significantly increased LH, FSH, and SHBG levels and conversely, decreased androstenedione (AE), E2 and TT levels. Additionally, the level of progesterone (P), prolactin (PRL), free testosterone (FT) and dehydroepiandrosterone sulfate (DHEA-S) showed no significant changes in patients who had undergone BS.

CONCLUSION

BS changed most sex hormones levels including LH, FSH, TT, SHBG, AE, DHEA, and E2. It seems that BS is able to exert substantial impacts on sex hormones levels and as well as sexual function, however, larger, and more precise trials are required to specifically focus on these claims.

GK-rats respond to gastric bypass surgery with improved glycemia despite unaffected insulin secretion and beta cell mass

Roux-en-Y gastric bypass (RYGB) is the most effective treatment for morbid obesity and results in rapid remission of type 2 diabetes (T2D), before significant weight loss occurs. The underlying mechanisms for T2D remission are not fully understood. To gain insight into these mechanisms we used RYGB-operated diabetic GK-rats and Wistar control rats. Twelve adult male Wistar- and twelve adult male GK-rats were subjected to RYGB- or sham-operation. Oral glucose tolerance tests (OGTT) were performed six weeks after surgery. RYGB normalized fasting glucose levels in GK-rats, without affecting fasting insulin levels. In both rat strains, RYGB caused increased postprandial responses in glucose, GLP-1, and GIP. RYGB caused elevated postprandial insulin secretion in Wistar-rats, but had no effect on insulin secretion in GK-rats. In agreement with this, RYGB improved HOMA-IR in GK-rats, but had no effect on HOMA-β. RYGB-operated GK-rats had an increased number of GIP receptor and GLP-1 receptor immunoreactive islet cells, but RYGB had no major effect on beta or alpha cell mass. Furthermore, in RYGB-operated GK-rats, increased Slc5a1, Pck2 and Pfkfb1 and reduced Fasn hepatic mRNA expression was observed. In summary, our data shows that RYGB induces T2D remission and enhanced postprandial incretin hormone secretion in GK-rats, without affecting insulin secretion or beta cell mass. Thus our data question the dogmatic view of how T2D remission is achieved and instead point at improved insulin sensitivity as the main mechanism of remission.

Immunometabolism, Micronutrients, and Bariatric Surgery: The Use of Transcriptomics and Microbiota-Targeted Therapies

BACKGROUND

Obesity is associated with the gut microbiota and decreased micronutrient status. Bariatric surgery is a recommended therapy for obesity. It can positively affect the composition of the gut bacteria but also disrupt absorption of nutrients. Low levels of micronutrients can affect metabolic processes, like glycolysis, TCA cycle, and oxidative phosphorylation, that are associated with the immune system also known as immunometabolism.

METHODS

MEDLINE, PUBMED, and Google Scholar were searched. Articles involving gut microbiome, micronutrient deficiency, gut-targeted therapies, transcriptome analysis, micronutrient supplementation, and bariatric surgery were included.

RESULTS

Studies show that micronutrients play a pivotal role in the intestinal immune system and regulating immunometabolism. Research demonstrates that gut-targeting therapies may improve the microbiome health for bariatric surgery populations. There is limited research that examines the role of micronutrients in modulating the gut microbiota among the bariatric surgery population.

CONCLUSIONS

Investigations are needed to understand the influence that micronutrient deficiencies have on the gut, particularly immunometabolism. Nutritional transcriptomics shows great potential in providing this type of analysis to develop gut-modulating therapies as well as more personalized nutrition recommendations for bariatric surgery patients.

The combined effects of probiotics and restricted calorie diet on the anthropometric indices, eating behavior, and hormone levels of obese women with food addiction a randomized clinical trial

BACKGROUND AND AIM

Food addiction (FA) is an important contributor to obesity. Alterations in gut microbiota (GM) diversity and composition have also been proposed to play a pivotal role in obesity pathogenesis. This trial aimed to assess the effects of probiotic supplementation on the anthropometric indices, eating behavior, and hormone levels of obese women with FA.

METHODS

This randomized, double-blind, placebo-controlled clinical trial was conducted among obese women with FA. Participants (n = 62) received a restricted calorie diet (RCD) plus either probiotic, or placebo for 12 weeks. Anthropometric measurements, biochemical markers, eating behavior and appetite were assessed during the study period.

RESULTS

Probiotics administration significantly reduced weight, body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR), body fat percentage (BFP), and trunk fat percentage (TFP) compared to the placebo group (p < 0.001). Also, a significant improvement was observed in eating behavior in the probiotic group compared to the placebo group (p < 0.001).Serum levels of oxytocin increased and NPY decreased significantly in the probiotic group compared to the placebo group (p = 0.02, p = 0.002, respectively). Moreover, leptin level significantly decreased in the probiotic group compared to the baseline values (p < 0.001), while probiotics did not cause a greater significant reduction in leptin level, compared to the placebo group.

CONCLUSION

Multi-probiotic supplementation may have beneficial effects on anthropometric indices, eating behavior, and some appetite-regulating hormones in obese women with FA.Trial registration: Iranian Registry of Clinical Trials identifier: IRCT20131228015968N5.

Surgery-Induced Weight Loss and Changes in Hormonally Active Fibroblast Growth Factors: a Systematic Review and Meta-Analysis

This systematic review and meta-analysis was performed to investigate the possible changes of FGF-19 and FGF-21 after bariatric surgery (BS). Electronic databases including PubMed and Scopus were systematically searched up to February 2020 to identify pertinent studies. A total of 25 different studies were included. The overall pooled analysis identified that BS caused a significant increase in FGF-19, but had no significant effect on FGF-21. For FGF-19, this finding was supported in the subgroup analyses. For FGF-21, Roux-en-Y gastric bypass (RYGB) surgery significantly increased FGF-21 levels, whereas, in studies with follow-up duration ≥ 1 year, FGF-21 levels decreased significantly. BS reduces circulating concentration of FGF-19, but might increase FGF-21 after RYGB or decrease FGF-21 after ≥ 1 year.

Protein, amino acids and obesity treatment

Dietary proteins have been used for years to treat obesity. Body weight loss is beneficial when it concerns fat mass, but loss of fat free mass - especially muscle might be detrimental. This occurs because protein breakdown predominates over synthesis, thus administering anabolic dietary compounds like proteins might counter fat free mass loss while allowing for fat mass loss.Indeed, varying the quantity of proteins will decrease muscle anabolic response and increase hyperphagia in rodents fed a low protein diet; but it will favor lean mass maintenance and promote satiety, in certain age groups of humans fed a high protein diet. Beyond protein quantity, protein source is an important metabolic regulator: whey protein and plant based diets exercize favorable effects on the risk of developing obesity, body composition, metabolic parameters or fat free mass preservation of obese patients. Specific amino-acids like branched chain amino acids (BCAA), methionine, tryptophan and its metabolites, and glutamate can also positively influence parameters and complications of obesity especially in rodent models, with less studies translating this in humans.Tuning the quality and quantity of proteins or even specific amino-acids can thus be seen as a potential therapeutic intervention on the body composition, metabolic syndrome parameters and appetite regulation of obese patients. Since these effects vary across age groups and much of the data comes from murine models, long-term prospective studies modulating proteins and amino acids in the human diet are needed.

Effect of Surgically Induced Weight Loss on Biomarkers of Endothelial Dysfunction: a Systematic Review and Meta-Analysis

BACKGROUND

This meta-analysis was performed to assess the effects of bariatric surgery (BS) on the selected markers of endothelial dysfunction, including monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and E-selectin.

METHODS

PubMed, Scopus, and Google scholar were systematically searched to identify related studies published from inception to November 2019 to find eligible studies.

RESULTS

A total of 29 different studies were included. BS reduced the concentrations of MCP-1 (weighted mean difference (WMD) = - 58.91; 95%CI (confidence interval), - 77.10 to - 40.72; P = ˂ 0.001), ICAM-1 (WMD = - 36.58; 95%CI, - 49.65 to - 23.52; P = ˂ 0.001), and E-selectin (WMD = - 11.22; 95%CI, - 14.43 to - 8.01; P < 0.001), but had no significant effect on VCAM-1.

CONCLUSION

Bariatric surgery reduces circulating concentration of MCP-1, ICAM-1, and E-selectin, but not VCAM-1.

In Terms of Nutrition, the Most Suitable Method for Bariatric Surgery: Laparoscopic Sleeve Gastrectomy or Roux-en-Y Gastric Bypass? A Systematic Review and Meta-analysis

This study assesses the differences in postoperative nutritional status between laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (LRYGB). We searched the literature from PubMed, Web of Science, Embase, and the Cochrane Library database. Twenty-nine articles were included, with a total of 5437 obese patients. After bariatric surgery, the LSG group had less anemia and iron deficiency anemia than the LRYGB group. The serum iron, ferritin deficiency, and vitamin B12 rates after LSG were lower than patients receiving LRYGB. And PTH and serum phosphorus concentration of patients after LSG were both lower than those after LRYGB. The postoperative results of LSG were better than that of LRYGB. Therefore, we recommend LSG for a better postoperative nutrition, but only for reference.

Microbial Adaptation Due to Gastric Bypass Surgery: The Nutritional Impact

Bariatric surgery leads to sustained weight loss and the resolution of obesity-related comorbidities. Recent studies have suggested that changes in gut microbiota are associated with the weight loss induced by bariatric surgery. Several studies have observed major changes in the microbial composition following gastric bypass surgery. However, there are inconsistencies between the reported alterations in microbial compositions in different studies. Furthermore, it is well established that diet is an important factor shaping the composition and function of intestinal microbiota. However, most studies on gastric bypass have not assessed the impact of dietary intake on the microbiome composition in general, let alone the impact of restrictive diets prior to bariatric surgery, which are recommended for reducing liver fat content and size. Thus, the relative impact of bariatric surgery on weight loss and gut microbiota remains unclear. Therefore, this review aims to provide a deeper understanding of the current knowledge of the changes in intestinal microbiota induced by bariatric surgery considering pre-surgical nutritional changes.

Bariatric Surgery in Obesity: Effects on Gut Microbiota and Micronutrient Status

Obesity is associated with reduced gut microbial diversity and a high rate of micronutrient deficiency. Bariatric surgery, the therapy of choice for severe obesity, produces sustained weight loss and improvements in obesity-related comorbidities. Also, it significantly alters the gut microbiota (GM) composition and function, which might have an important impact on the micronutrient status as GM is able to synthesize certain vitamins, such as riboflavin, folate, B12, or vitamin K2. However, recent data have reported that GM is not fully restored after bariatric surgery; therefore, manipulation of GM through probiotics represents a promising therapeutic approach in bariatric patients. In this review, we discuss the latest evidence concerning the relationship between obesity, GM and micronutrients, the impact of bariatric surgery on GM in relation with micronutrients equilibrium, and the importance of the probiotics' supplementation in obese patients submitted to surgical treatment.

Nutritional and perinatal outcomes of pregnant women with a history of bariatric surgery: a case series from a UK centre

BACKGROUND

Women with obesity who become pregnant after bariatric surgery have a reduced risk of several obstetric complications; however, limited data exist from the UK population. The present study aimed to characterise a case series of women who attended a medical antenatal clinic for pregnancy following bariatric surgery.

METHODS

Routine clinical information was collected retrospectively from the medical notes of women who had bariatric surgery and subsequently delivered between January 2012 and November 2018. All were seen in the medical antenatal clinic at Musgrove Park Hospital, Taunton.

RESULTS

Data were available for 46 pregnancies. Of these, 27.9% conceived in the first year after surgery. At 9 weeks of gestation, 13.3%, 28.9%, 33.3% and 24.4% were in the healthy, overweight, obese or severely obese category, respectively. Mean (SD) gestational weight gain was 11.9 (6.9) kg, with 54.1% gaining excess weight. Less than half (39.1%) of women were taking the recommended dose of 5 mg of folic acid when first seen. Some 56.1% and 64.6% had suboptimal iron or vitamin D statuses, respectively. Following advice from the clinic, a greater proportion of women took suitable micronutrient supplements. Subsequently, 93% of babies were born at full term, of whom 88% were of healthy weight.

CONCLUSIONS

Despite the nutritional risks associated with bariatric surgery and the high prevalence of obesity during pregnancy, perinatal outcomes were generally positive, with low rates of infants born preterm or low birth weight. Nutritional supplementation practices and iron status improved with input from a specialist team, underlying the importance of individualised input in this population.

What Is Known About the Nutritional Intake of Women during Pregnancy Following Bariatric Surgery? A Scoping Review

Optimising the diet and weight of women prior to and during pregnancy is of paramount importance to both maternal and offspring health. In women who become pregnant after bariatric surgery, evidence suggests a better overall obstetric outcome in comparison to women with severe obesity managed conservatively. Historically, most studies in this population group have monitored supplement adherence or serum concentrations of micronutrients, rather than dietary intake. The aim of this study was to synthesise current knowledge of the dietary intake of women during pregnancy following bariatric surgery. A systematic search of search engines was conducted using the following databases: MEDLINE, Embase, CINAHL, Cochrane database, Scopus, Trip, NHS Evidence, UK Clinical Trials, ClinicalTrials.gov, Prospero, Epistemonikos and Open Grey. Titles and abstracts were screened independently by two reviewers against predefined inclusion and exclusion criteria. After removal of duplicates, 1594 titles were identified, of which 1586 were initially excluded. Following full-text review, four articles were included. In total, across all four studies, data from only 202 bariatric surgery participants were included, the majority of whom had had one type of surgery. Just one study included a control group. Reporting of nutritional outcomes was heterogenous, with none of the studies including complete macro and micronutrient intake results in their articles. An insufficient intake of protein was noted as a concern in two studies and associated with poor fetal growth in one study. Overall, this review has identified a paucity of data about the dietary intake of women during pregnancy after bariatric surgery.