Change in liver size and fat content after treatment with Optifast very low calorie diet

Metabolic signatures of metabolic dysfunction-associated steatotic liver disease in severely obese patients

BACKROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) can lead to liver fibrosis, cirrhosis, and hepatocellular carcinoma. Still, most patients with MASLD die from cardiovascular diseases indicating metabolic alterations related to both liver and cardiovascular pathology.

AIMS AND METHODS

The aim of this study was to assess biologic pathways behind MASLD progression from steatosis to metabolic dysfunction-associated steatohepatitis (MASH) using non-targeted liquid chromatography-mass spectrometry analysis in 106 severely obese individuals (78 women, mean age 47.7 7 ± 9.2 years, body mass index 41.8 ± 4.3 kg/m²) undergoing laparoscopic Roux-en-Y gastric bypass.

RESULTS

We identified several metabolites that are associated with MASLD progression. Most importantly, we observed a decrease of lysophosphatidylcholines LPC(18:2), LPC(18:3), and LPC(20:3) and increase of xanthine when comparing those with steatosis to those with MASH. We found that indole propionic acid and threonine were negatively correlated to fibrosis, but not with the metabolic disturbances associated with cardiovascular risk. Xanthine, ketoleucine, and tryptophan were positively correlated to lobular inflammation and ballooning but also with insulin resistance, and dyslipidemia, respectively. The results did not change when taking into account the most important genetic risk factors of MASLD.

CONCLUSIONS

Our findings suggest that there are several separate biological pathways, some of them independent of insulin resistance and dyslipidemia, associating with MASLD.

Long-Term Outcomes of Recipients of Liver Transplants from Living Donors Treated with a Very Low-Calorie Diet

The increasing prevalence of steatotic liver disease (SLD) in potential living donors is concerning, as it limits donor's availability amid rising demand. OPTIFAST very low-calorie diet (VLCD), a meal replacement product, effectively reduces weight and hepatic steatosis before transplantation. However, data on the outcomes of recipients of VLCD-treated donors are lacking. We conducted a single-center, retrospective study on 199 living donor liver transplant recipients at Toronto General Hospital, Canada, between January 2015 and January 2020. We compared the 1-year posttransplant outcomes between recipients who received organs from donors treated with VLCD (N = 34) for either weight loss or steatosis reduction, with those who did not require treatment (N = 165). Our analysis revealed no statistically significant differences in the rates of postoperative complications (23% vs 32.4%, p=0.3) or intensive care unit stays (70.9% vs 70.6%, p=1) between recipients of non-VLCD and VLCD grafts. Following adjusted multivariate logistic regression, receipt of VLCD grafts was not associated with increased hospital length of stay. In addition, one-year mortality did not differ between the two groups (4.2% non-VLCD recipients vs 2.9% VLCD recipients, p=0.6). OPTIFAST VLCD treatment for liver donors demonstrates positive and safe outcomes in recipients, expanding the pool of potential living donors for increased organ availability.

The OPTIFAST total and partial meal replacement programme reduces cardiometabolic risk in adults with obesity: Secondary and exploratory analysis of the OPTIWIN study

AIM

The effects of weight loss with a partial or total meal replacement programme (MRP) on atherosclerotic cardiovascular disease (ASCVD) risk factors are not fully understood, in particular in people at higher CV risk. In the 52-week randomized controlled OPTIWIN study in men and women with obesity, meal replacement programme (total for first 26 weeks, partial for the ensuing 26 weeks) with OPTIFAST (OP) resulted in significantly greater weight loss compared with a low-calorie food-based (FB) dietary plan, both as part of a comprehensive lifestyle intervention [OP (n = 135)/FB (n = 138) week 26: -12.4%/-6.0%, p < .001; week 52: -10.5%/-5.5%, p < .001]. Here, we examined effects on ASCVD risk factors and 10-year ASCVD risk.

MATERIALS AND METHODS

Participants with body mass index 30-55 kg/m2 and age 18-70 years, and not on anti-obesity medications, were recruited. The effects on systolic and diastolic blood pressure (SBP, DBP), lipid parameters and 10-year ASCVD risk were analysed as changes over time using linear mixed models. Subgroup analyses were conducted for changes in SBP, DBP and ASCVD risk by categories of age (<40, 40-59, ≥60 years), baseline SBP (

RESULTS

Baseline characteristics were well balanced (OP/FB females 86%/79%, mean age 47/47 years, body mass index 38.4/39.2 kg/m2 , 10-year ASCVD risk <5% 87%/74%, dysglycaemia 52%/50%). At week 26, SBP/DBP were significantly reduced with OP versus FB, and a greater proportion achieved BP ≤130/80 mmHg [odds ratio 2.11 (95% confidence interval 1.10, 4.03), p = .024]. All lipid parameters as well as 10-year ASCVD risk were significantly improved with OP versus FB. A similar, but slightly attenuated pattern was observed at 52 weeks. Across subgroups, greater reductions for SBP, DBP and ASCVD risk were generally seen with OP versus FB with quantitatively higher baseline SBP and age, and in men.

CONCLUSIONS

In people with obesity at low ASCVD risk, OP significantly reduced cardiovascular risk factors and 10-year predicted risk for ASCVD.

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Key Words

• blood pressure
• body weight
• caloric restriction
• clinical trial
• heart disease risk factors
• obesity management

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MESH Headings

• Adult
• Male
• Humans
• Female
• Middle Aged
• Adolescent
• Young Adult
• Aged
• Obesity/complications
• Obesity/epidemiology
• Blood Pressure
• Risk Factors
• Weight Loss
• Atherosclerosis
• Lipids
• Hypertension/drug therapy

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Grants

• Nestlé Health Science

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Affiliation(s)

Jamy D Ard Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
Ian J Neeland Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
Amy E Rothberg University of Michigan, Ann Arbor, Michigan, USA
Robert J Chilton University of Texas Health Science Center, San Antonio, Texas, USA
Daniel de Luis Center of Investigation of Endocrinlogy and Nutrition, University of Valladolid, Hospital clínico Universitario de Valladolid, Valladolid, Spain
Sarah S Cohen EpidStrategies, A Division of Tox Strategies Inc., Katy, Texas, USA
Odd Erik Johansen Nestlé Health Science, Lausanne, Switzerland

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Preoperative Assessment of a Patient Undergoing Bariatric Surgery

Over the past few decades, obesity rates in the United States have risen drastically, and with this, there has been a rising demand for bariatric surgery. As such, anesthesiologists need to be familiar with the challenges presented by patients seeking bariatric surgery. Obesity causes pathophysiologic changes which may affect decision-making during the management of these patients. Patients seeking bariatric surgery also have a long, prescribed preoperative course that offers anesthesiologists the opportunity to be involved earlier during the pre-surgical evaluation and optimization process.

Evaluating the evidence for a liver shrinkage diet for obese patients prior to laparoscopic cholecystectomy: A systematic review and meta-analysis

BACKGROUND

The role of a very low-calorie diet (VLCD) before cholecystectomy in obese patients is unclear. This study evaluated whether VLCD could be used as a risk mitigation strategy for this high-risk patient cohort.

PATIENTS AND METHODS

A systematic review and meta-analysis was performed (PROSPERO ID CRD42022374610). The primary outcome was to determine the impact of pre-operative VLCD on the operative findings and ease of dissection during laparoscopic cholecystectomy (LC).

RESULTS

Two studies were included with a total of 84 patients. VLCD was associated with a significantly easier Calot's dissection (MD: -0.58 (95% confidence interval [CI] [ -1.03, -0.13], P = 0.01) and was associated with a significantly higher rate of pre-operative weight loss (MD; 2.92 (95% CI [2.23, 3.62], P = 0.00001).

CONCLUSIONS

The published evidence regarding VLCD before cholecystectomy in obese patients is limited. After acknowledging the limitations of the data, VLCD is associated with a significantly higher rate of weight loss preoperatively and directly impacts the ease of intraoperative dissection of Calot's triangle. Routine use of VLCD should be considered for all obese patients undergoing elective LC.

Defining Physiological Ketosis Following Very-Low-Calorie Diets

INTRODUCTION

Very low-calorie diets (VLCDs) are used preoperatively in bariatric-metabolic surgery; however, this can lead to physiological ketosis. Euglycemic ketoacidosis is an increasingly recognized complication in diabetic patients on sodium-glucose-cotransporter-2 inhibitors (SGLT2i) undergoing surgery and requires assessment of ketones for diagnosis and monitoring. VLCD induced ketosis may confound monitoring in this group. We aimed to evaluate the influence of VLCD, compared to standard fasting, on perioperative ketone levels and acid-base balance.

MATERIALS AND METHODS

Twenty-seven patients were prospectively recruited to the intervention group and 26 to the control group from two tertiary referral centres in Melbourne, Australia. Intervention group patients were severely obese (body mass index) (BMI) (≥35), undergoing bariatric-metabolic surgery, and prescribed 2 wk of VLCD preoperatively. Control group patients underwent general surgical procedures and prescribed standard procedural fasting only. Patients were excluded if diabetic or prescribed SGLT2i. Ketone and acid-base measurements were taken at regular intervals. Univariate and multivariate regression was utilised with significance defined as P < 0.005.

CLINICALTRIALS

gov ID: NCT05442918.

RESULTS

Patients on VLCD, compared to standard fasting, had an increased median preoperative (0.60 versus 0.21 mmol/L), immediate postoperative (0.99 versus 0.34 mmol/L) and day 1 postoperative (0.69 versus 0.21 mmol/L) ketone level (P < 0.001). Preoperative acid-base balance was normal in both groups, however VLCD patients were found to have a metabolic acidosis immediately postoperatively (pH 7.29 versus pH 7.35) (P = 0.019). Acid-base balance had normalized in VLCD patients on postoperative day 1.

CONCLUSIONS

Preoperative VLCD resulted in increased pre- and postoperative ketone levels with immediate postoperative values consistent with metabolic ketoacidosis. This should be considered particularly when monitoring diabetic patients prescribed SGLT2i.

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

Only in the USA, 315 billion dollars are spent annually on the medical cost of obesity in adult patients. Till now, bariatric surgery is the most effective method for treating obesity and can play an essential role in reducing the direct and indirect costs of obesity treatment. Nonetheless, there are few comprehensive guidelines which include nutrition, physical activity, and supplements, before and after surgery. The purpose of the present narrative review is to provide an updated and comprehensive practical guideline to help multidisciplinary teams. The core keywords include 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 which were searched in databases including PubMed/Medline, Cochrane, and some other sources such as Google Scholar. We answered questions in five important areas: (a) nutritional strategies before bariatric surgery, (b) nutrition after bariatric surgery, (c) physical activity before and after bariatric surgery, (d) weight regain after bariatric surgery, and (e) micronutrient assessments and recommendations before and after bariatric surgery. Some new items were added in this updated guideline including "weight regain" and "pregnancy after bariatric surgery." Other fields were updated based on new evidence and guidelines.

INTRAGASTRIC BALLOON AND IMPACT ON WEIGHT LOSS: EXPERIENCE IN QUITO, EQUADOR

BACKGROUND

Obesity is associated with different medical conditions, such as cardiologic, respiratory, gastrointestinal, and genitourinary, and constitutes a severe health problem.

AIMS

This study aimed to evaluate the use of intragastric fluid-filled balloon in the reduction of weight and other measurements related to body composition.

METHODS

This is a retrospective, monocentric study involving all patients who opted for the intragastric balloon Spatz® placement from January 2018 to July 2019, with fulfillment of inclusion and exclusion criteria. The patients were analyzed after 6 and 12 months after the intragastric fluid-filled balloon placed.

RESULTS

A total of 121 subjects were included in this study, with 83 (68.6%) females and 38 (31.4%) males. The mean age was 36 years and height was 1.64±0.09. Weight mean and standard deviation was 89.85±14.65 kg, and body mass index was 33.05±4.03; body mass index decreased to 29.4 kg/m2 with a mean weight of 79.83 kg, after 12 months of follow-up. There were statistical differences between body mass index and the 12 months in fat percentage, fat-free mass (kg), visceral fat area, and basal metabolic rate. There was a significant variation according to gender, with males having highest reduction. The percentage of excess weight loss was 46.19, and the total weight loss was 9.24 at the end of the study.

CONCLUSIONS

The study demonstrated a benefit of intragastric fluid-filled balloon on weight loss after 12 months. At the end of treatment, body mass index and the measurements of body composition were significantly lower. Men benefited more than women from the treatment.

Biomarkers reflecting pericellular fibrosis improve together with liver histology after bariatric surgery in early non-alcoholic fatty liver disease

AIM

Non-invasive tests for non-alcoholic fatty liver disease (NAFLD) are needed for assessing disease stage, prognosis and treatment efficacy. Extracellular matrix biomarkers, such as PRO-C3, are useful as biomarkers of advanced liver fibrosis. However, non-invasive biomarkers of early-stage NAFLD, characterized by pericellular fibrosis, are lacking. Here, we measured serological biomarkers of type IV and VIII collagens reflecting the remodeling of the pericellular basement membrane to explore the effect of bariatric surgery on pericellular fibrosis in patients with early NAFLD.

METHODS

Seventy patients with severe obesity underwent bariatric surgery. The cohort consisted of 61 % females who had a mean age of 44. Patients had a median NAFLD activity score of 3 and mild-to-moderate fibrosis F0 (3 %), F1 (86 %), and F2 (11 %). Blood samples were taken at baseline, three, six and 12 months after surgery. At 12 months, 40 patients had a follow-up liver biopsy. The biomarkers PRO-C3, PRO-C4, C4M, and PRO-C8 were measured using indirect competitive ELISAs.

RESULTS

Twelve months after surgery patients had significantly lower levels of ALT, GGT, HbA1c, fasting glucose, and CRP. The pericellular fibrosis biomarkers, C4M, PRO-C4, and PRO-C8 decreased by 24 %, 18 % and 44 %, respectively (p < 0.0001), while the interstitial matrix fibrosis marker PRO-C3 remained unchanged. Furthermore, baseline C4M was associated with histologically assessed hepatocyte ballooning and lobular inflammation in patients with (p = 0.032) and without (p = 0.032) steatosis, respectively.

CONCLUSION

Biomarkers of pericellular fibrosis decrease in early-stage NAFLD after patients undergo bariatric surgery and potentially reflect an improvement in liver histology.

Very low-calorie ketogenic diet rapidly augments testosterone levels in non-diabetic obese subjects

BACKGROUND

The very low-calorie ketogenic diet (VLCKD) represents an opportunity to attain clinically relevant weight loss in obese patients. Functional hypogonadism represents a frequent hormonal disorder associated with obesity and visceral fat accumulation characterised by low testosterone levels and subnormal luteinising hormone (LH) levels.

AIM

To evaluate the early effects of VLCKD on serum total testosterone (TT) levels in non-diabetic obese patients.

METHODS

Twenty-two obese male patients (mean age 39.3 ± 11.7 years, mean body mass index (BMI) 38.2 ± 6.4 kg/m² ) were enrolled and treated for 28 days with VLCKD. Anthropometric and hormonal variables were assessed before, during and after diet intervention.

RESULTS

After 7 and 28 days on a VLCKD, a significant and persistent reduction in body weight, BMI, fat mass, blood glucose, insulin and homeostasis model assessment index was observed compared with baseline. TT significantly increased after 7 days (+35 ± 64 ng/dl) and 28 days (+74 ± 97 ng/dl) on a VLCKD. In addition to TT, a significant increase in serum sex hormone-binding globulin levels was observed after 7 (+2.1 ± 4.1) and 28 days (+7.7 ± 10.0). However, both calculated free testosterone and LH did not change after 7 or 28 days of VLCKD. Following cessation of VLCKD, hypogonadal subjects achieved a higher percentage of total weight loss (8.5% ± 1.5%), a greater reduction in weight (-9.94 ± 1.66 kg), fat mass (-7 ± 2.1 kg) and waist circumference (-6.31 ± 2.65 cm) and a greater improvement in glycaemia (-8.75 ± 10.92 mg/dl) as compared with eugonadal subjects. Furthermore, hypogonadal subjects exhibited a trend of higher TT increase (+98.12 ± 71.51 ng/dl) as compared with eugonadal subjects.

CONCLUSIONS

VLCKD results in rapid improvements in TT levels associated with weight loss in male obese non-diabetic subjects, particularly in the presence of obesity-related hypogonadism.

Comparison of a pre-bariatric surgery very low-calorie ketogenic diet and the Mediterranean diet effects on weight loss, metabolic parameters, and liver size reduction

This study compared the effects on weight as well as on metabolic parameters and liver size of a very low-calorie ketogenic diet versus a Mediterranean diet in patients with morbid obesity preparing to undergo bariatric surgery. This prospective comparison study evaluated patients 18-65 years of age who enrolled for bariatric surgery. Study duration was limited to an immediate preoperative period of 15 days. The very low-calorie ketogenic diet incorporated 10-12 kcal/kg/day of energy and 1-1.2 g/kg of protein using Kalibra (Societa Dietetica Medica) (VLCKD-SDM). The Mediterranean diet (MD) included 15-20% protein, 45-50% carbohydrate, and 25-35% fat. Changes in body mass index (BMI), liver size, and anthropometric and metabolic measurements were assessed. Between January 2016 and March 2017, of 45 patients enrolled, 30 completed the study (VLCKD-SDM, n = 15; MD, n = 15). Respective median BMI loss after VLCKD-SDM was 2.7 kg/m² versus MD 1.4 kg/m² (p < 0.05); median fat percentage reduction was 3.2 units versus 1.7 units (p < 0.05). Median liver size decreased 5.5% in the VLCKD-SDM group versus 1.7% in the MD group (p < 0.05). Median total cholesterol, and LDL levels decreased in both groups (p < 0.05), with greater relative decreases in the VLCKD-SDM group. Short-term preoperative diet-based weight loss in patients with morbid obesity preparing for bariatric surgery was significantly greater following a very low-calorie ketogenic diet versus a Mediterranean diet. The very low-calorie diet also significantly improved anthropometric and metabolic parameters and reduced preoperative liver size above that of the MD.

Effect of silymarin on liver size and nonalcoholic fatty liver disease in morbidly obese patients: A randomized double-blind clinical trial

BACKGROUND

A large liver size is a factor that may increase the difficulty of bariatric surgery (BS) and unwanted complications. Some agents have been used to decrease the liver size before BS. Silymarin has been used as an antioxidant agent to improve liver function tests. This study was designed to evaluate the effects of silymarin on liver dimensions, function, and lipid profile.

MATERIALS AND METHODS

A double-blind randomized clinical trial was performed on 56 patients. The patients were divided into silymarin and placebo groups. Blood samples and sonographic examinations were taken from the patients before and 4 weeks after the administration of the silymarin or placebo. In the first group, 140 mg silymarin was prescribed every 8 h for 4 weeks, and the other group received placebo in the same way with the same tablet shape. After the completion of the 4-week treatment, laboratory tests and ultrasonography were carried out again.

RESULTS

Thirty-nine (69.6%) patients were female with a mean body mass index (BMI) of 46.2 kg/m² and a mean age of 36.8 years. Most of the patients had a compliance of 80% and higher. The analysis did not show any significant difference in aspartate transaminase, alkaline transaminase, liver size, cholesterol, and triglyceride changes among the silymarin and placebo groups. BMI loss was slightly higher in the silymarin group although the difference was not statistically significant.

CONCLUSION

The present findings show that silymarin administration for 4 weeks does not affect liver size and function, but further evaluations should be carried out on the subject.

Effect of progressive resistance training with weight loss compared with weight loss alone on the fatty liver index in older adults with type 2 diabetes: secondary analysis of a 12-month randomized controlled trial

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) is highly prevalent (~75%) in people with type 2 diabetes (T2D). Since exercise and weight loss (WL) are recommended for the management of both NAFLD and T2D, this study examined whether progressive resistance training (PRT) plus WL could lead to greater improvements in the fatty liver index (FLI), an indicator of NAFLD, compared with WL alone in older adults with T2D.

RESEARCH DESIGN AND METHODS

This study represents a secondary analysis of a 12-month, two-arm randomised controlled trial including 36 overweight and obese adults (60-80 years) with T2D randomly allocated to supervised PRT plus WL (hypocaloric diet) (n=19) or WL plus sham (stretching) (n=17) for 6 months (phase I), followed by 6-months home-based training with ad libitum diet (phase II). FLI, which is an algorithm based on waist circumference, body mass index, triglycerides and gamma-glutamyl transferase, was assessed at baseline and every 3 months. Linear mixed models were used to analyse between-group differences over time, adjusting for baseline values.

RESULTS

At baseline, the mean±SD FLI was 76.6±18.5 and the likelihood of NAFLD (FLI >60) in all participants was 86%. Following phase I, both groups had similar statistically significant improvements in FLI (mean change (95% CI): PRT+WL, -12 (-20 to -4); WL, -9 (-15 to -4)), with no significant between-group difference. After the subsequent 6-month home-based phase, the improvements in FLI tended to persist in both groups (PRT+WL, -7 (-11 to -2); WL, -4 (-10 to 1)), with no between-group differences.

CONCLUSIONS

In older overweight adults with T2D, PRT did not enhance the benefits of WL on FLI, a predictor of NAFLD.

TRIAL REGISTRATION NUMBER

ACTRN12622000640707.

The use of very low-calorie diets in subjects with obesity complicated with nonalcoholic fatty liver disease: A scoping review

This scoping review synthesizes the existing research on the use of very low-calorie diets (VLCDs) in subjects with nonalcoholic fatty liver disease (NAFLD) and end-stage liver disease (ESLD). 19 studies were included, of which 5 were clinical trials, 11 were cohort studies, 1 was a case-control study, and 2 were case series totaling 968 subjects. About 17 studies were focused on patients with NAFLD while the two case series described in patients with ESLD on the transplant list or post-liver transplant. Six studies included subjects managed with VLCDs prior bariatric surgery. Most studies were short term and demonstrated acute improvement of diverse liver biomarkers including liver function tests, indices of hepatosteatosis and reduction in liver size. Adherence rates in these studies were between 69% and 93%. Eight studies did not report any adverse events and four subjects were reported to have discontinued VLCD due to adverse effects in two different studies. Aggregated adverse events were mild. Treatments based on VLCD in subjects with NAFLD seem to be safe and tolerable but can result in mild adverse effects. The findings of this scoping review suggest that the use of VLCD in patients with obesity complicated with NAFLD and potentially in ESLD appear to be effective to induce weight loss and to acutely reduce hepatosteatosis.

Reliability and accuracy of straightforward measurements for liver volume determination in ultrasound and computed tomography compared to real volumetry

To evaluate the suitability of volume index measurement (VI) by either ultrasound (US) or computed tomography (CT) for the assessment of liver volume. Fifty-nine patients, 21 women, with a mean age of 66.8 ± 12.6 years underwent US of the liver followed immediately by abdominal CT. In US and CT imaging dorsoventral, mediolateral and craniocaudal liver diameters in their maximum extensions were assessed by two observers. VI was calculated by multiplication of the diameters divided by a constant (3.6). The liver volume determined by a manual segmentation in CT ("true liver volume") served as gold standard. True liver volume and calculated VI determined by US and CT were compared using Bland-Altman analysis. Mean differences of VI between observers were - 34.7% (- 90.1%; 20.7%) for the US-based and 1.1% (- 16.1%; 18.2%) for the CT-based technique, respectively. Liver volumes determined by semi-automated segmentation, US-based VI and CT-based VI, were as follows: 1.500 ± 347cm³; 863 ± 371cm³; 1.509 ± 432cm³. Results showed a great discrepancy between US-based VI and true liver volume with a mean bias of 58.3 ± 66.9%, and high agreement between CT-based VI and true liver volume with a low mean difference of 4.4 ± 28.3%. Volume index based on CT diameters is a reliable, fast and simple approach for estimating liver volume and can therefore be recommended for clinical practice. The usage of US-based volume index for assessment of liver volume should not be used due to its low accuracy of US in measurement of liver diameters.

Effectiveness and Tolerability of a Two-Week Hypocaloric Protein-Rich Diet Prior to Obesity Surgery with Two Different Diet Interventions: a Prospective Randomized Trial

Purpose

Preoperative very low-calorie diets (VLCDs) have been shown to reduce liver volume and improve bariatric surgery safety. Here, we compare two VLCD that differ in macronutrient composition.

Material/Methods

Ninety patients awaiting obesity surgery were included in a prospective, open-label, randomized mono-centre trial comparing the effects of 2-week preoperative VLCDs: BCM Diät™ (diet 1) versus Optifast™ (diet 2).

Results

Data from 33 patients in diet 1 and 36 in diet 2 could be analysed. There was no significant difference between the two diet intervention arms on outcome parameters. Overall, both VLCD strategies led to a mean weight reduction of 5.24 [4.72–5.76] kg (p < 0.001), mean excess weight loss was 8.2 [7.4–9.1] % (p < 0.001). BMI reduction was 1.81 [1.63–1.99] kg/m² (p < 0.001). Over all patients, the liver volume was reduced by 397 [329–466] ml (p < 0.001), which corresponds to 14.6 [12.4; 16.8] %. Liver fat content was significantly reduced by 18.35 [8.98–27.71] %. Reduction of body weight correlates with liver volume loss.

In addition, hip/waist circumferences, body fat and fat-free mass decreased significantly. We found an increase of ALAT/ASAT and a significant decrease of triglycerides, LDL-cholesterol and HbA1c. Parameters of inflammatory were significantly reduced upon VLCD.

Conclusion

Independently of the macronutrient composition, VLCD leads to a significant decrease of body weight, reduction of liver volume and improved parameters of inflammation, glucose and lipid metabolism. Preoperative diets are widely used in conditioning; however, VLCD should be considered as option for patients with obesity undergoing other abdominal surgeries.

Graphical abstract

Anesthesia and Enhanced Recovery After Surgery in Bariatric Surgery

The Enhanced Recovery After Surgery Society published guidelines for bariatric surgery reviewing the evidence and providing specific care recommendations. These guidelines emphasize preoperative nutrition, multimodal analgesia, postoperative nausea and vomiting prophylaxis, anesthetic technique, nutrition, and mobilization. Several studies have since evaluated these pathways, showing them to be safe and effective at decreasing hospital length of stay and postoperative nausea and vomiting. This article emphasizes anesthetic management in the perioperative period and outlines future directions, including the application of Enhanced Recovery After Surgery principles in patients with extreme obesity, diabetes, and metabolic disease and standardization of the pathways to decrease heterogeneity.

Is there a role for preoperative liver reducing diet in hepatectomy? A systematic review

PURPOSE

Preoperative very low-calorie diets (VLCDs) have been shown to reduce liver volume, reduce the risk of liver injury and improve safety during bariatric surgery. Hepatic steatosis (HS) has been associated with poorer outcomes in liver resection. VLCD can be used to improve HS. We aim to explore if preoperative VLCD could improve outcomes for patients with HS undergoing liver resection.

METHODS

We performed a systematic review of MEDLINE, EMBASE, PubMed and Cochrane databases. Studies were included if they were full-text articles investigating the effect of a preoperative dietary intervention in patients undergoing liver resection on intra-operative and post-operative outcomes. The last search was performed on 11 Jun 2020. Evidence quality was assessed by "GRADE". A narrative review was undertaken.

RESULTS

Five studies were found: one RCT and four cohort studies including 133 patients in intervention groups and 181 controls. Three used diet-only strategies and two diet and exercise strategies with varying time courses and monitoring. The quality of evidence assessed by GRADE was "high" for the RCT and "low" for the four cohort studies. Steatosis objectively improved in three studies, with evidence of reduced liver volume and increased attenuation on imaging in one. All studies showed a reduction in body weight and body mass index (BMI). Intra-operative blood loss was decreased following a diet-only intervention in two studies, and liver mobility improved in one. No difference was found in morbidity, mortality or hospital length of stay between intervention and control groups.

CONCLUSIONS

There is evidence of poorer outcomes in liver resection patients with existing HS. There is an expected role for a preoperative VLCD to optimise these patients for surgery. Existing publications support this, but diet interventions and outcome measures are inconsistent, and patient numbers are small. There is scope for a well-designed, multi-centre randomised trial to investigate this further.

Weight loss interventions and nonalcoholic fatty liver disease: Optimizing liver outcomes

The growth in prevalence of obesity, type 2 diabetes and nonalcoholic fatty liver disease (NAFLD) has become one of the most important global health challenges. The three chronic diseases are closely linked in their epidemiology and pathophysiology. Currently, weight loss is the most effective treatment for NAFLD (even in the minority of patients with NAFLD who do not have obesity) and is recommended in all national and international guidelines. Accumulating evidence has shown that weight loss, whether achieved by diet and lifestyle interventions, bariatric surgery or pharmacotherapy, can improve biomarkers of NAFLD, as well as prevent progression and, in some cases, reverse fibrosis. There is a dose dependency of weight loss with NAFLD improvement. Pharmacotherapy with antiobesity medications, alone or in combination with intensive lifestyle interventions or other weight-loss drugs, is closing the efficacy gap between diet and exercise and weight-loss surgery in efficacy at reversing obesity. Given the importance of providing effective weight-loss treatment to patients with NAFLD, weight management services need to be made increasingly available and embedded within hepatology services. This narrative review addresses the evidence that weight loss optimizes liver outcomes in people with NAFLD.

Preoperative Weight Loss as a Predictor of Bariatric Surgery Postoperative Weight Loss and Complications

BACKGROUND

The association between preoperative weight loss and bariatric surgery outcomes remains unclear. We explored the utility of preoperative weight loss as a predictor of postoperative weight loss success. Additionally, we examined the association of preoperative weight loss with perioperative complication rates.

METHODS

Retrospective chart review of patients who underwent primary sleeve gastrectomy or primary Roux-en-Y gastric bypass for weight loss at a single institution between January 2003 and November 2017. Additional follow-up was obtained by a postoperative standardized patient questionnaire. Statistical analysis consisted of bivariate and multivariate logistic regression analysis.

RESULTS

Our study included 427 patients. Majority were female (n = 313, 73.3%) and underwent sleeve gastrectomy (n = 261, 61.1%). Average age was 45.6 years, and average follow-up was 6.3 years. Greater preoperative weight loss was associated with decreased length of stay (1.8 vs 1.3 days) in patients who underwent sleeve gastrectomy. Multivariable regression analysis revealed that preoperative weight loss was not associated with postoperative weight loss.

CONCLUSIONS

Preoperative weight loss is not predictive of postoperative weight loss success after bariatric surgery. Greater preoperative weight loss was associated with a mild decreased in length of stay but was not associated with a reduction in operative time, overall complication rates, ICU admissions, or intraoperative complications. The inconclusive literature and our findings do not support the medical necessity of weight loss prior to bariatric surgery for the purpose of reducing surgical complications or predicting successful postoperative weight loss success.

What Is the Optimal Time on a Low-Calorie Diet Prior to Laparoscopic Anti-reflux Surgery? A Prospective Case-Controlled Study

INTRODUCTION

A very low-calorie diet (VLCD) or low-calorie diet (LCD) is often used prior to laparoscopic surgery to optimize access to the hiatus. Much debate exists in the literature regarding the required duration for a VLCD or LCD, and how to evaluate the presence of a fatty liver. The aim of our study was to determine the optimal amount of time on an LCD to achieve maximal liver volume reduction, and to assess the accuracy of the InBody 230® vs. bedside ultrasonography vs. magnetic resonance imaging (MRI) in the measurement of liver volume.

METHODS

Seventeen consecutive patients undergoing laparoscopic anti-reflux surgery were recruited into the study. Each patient underwent body composition analysis with the InBody® 230, liver ultrasound, and liver MRI. Patients then began an LCD with a weekly ultrasound assessment until the day before surgery when they underwent repeat body composition analysis, liver ultrasound, and MRI.

RESULTS

The mean age was 54 years (range 21, 74). Maximal liver volume loss was noted within 3 weeks for 88% of participants, with 47% achieving their maximal liver volume reduction after the first week of an LCD. The mean reduction in liver volume was 16%, 18.6%, and 19% for MRI, ultrasound, and body composition analysis, respectively.

CONCLUSION

Close to 90% of patients require 3 weeks or less on an LCD to achieve maximal liver volume loss prior to laparoscopic anti-reflux surgery. Body composition analysis and bedside ultrasonography were both as accurate as the gold standard MRI in the assessment of liver volume.

Five Years of MBSAQIP Data: Characteristics, Outcomes, and Trends for Patients with Super-obesity

PURPOSE

Incidence of super obesity (SO; BMI ≥ 50 kg/m²) is growing rapidly and confers worse metabolic complications than non-SO (BMI 30-50 kg/m²). We aim to characterize bariatric surgery patients with SO, their postoperative complications, and treatment trends over the last 5 years in hopes of informing SO-specific treatment protocols.

MATERIALS AND METHODS

The MBSAQIP database was analyzed, and two cohorts were compared, those with SO and non-SO. Univariate analysis was performed to determine between-group differences. Multivariable logistic regression analysis was performed to determine if SO was independently associated with serious complications or mortality.

RESULTS

We evaluated 751,952 patients with 173,110 (23.0%) having SO. Patients with SO were younger (42.2 ± 11.8 SO vs 45.1 ± 12.0 years non-SO, p < 0.001) and less likely to be female (74.8% vs 81.1%, p < 0.001). While comorbidities seem to be decreasing overall in bariatric surgery patients, those with SO have worse functional capacity and more endocrine, pulmonary, and vascular comorbidities. Patients with SO also have worse 30-day postoperative complications, and SO was independently associated with severe complications (OR 1.08; CI 1.05-1.11, p < 0.001) and mortality (OR 2.49; CI 2.12-2.92, p < 0.001) CONCLUSIONS: Patients with SO have significantly increased preoperative comorbidities resulting in worse postoperative outcomes. SO remains an independent risk factor for serious complications and the greatest independent risk factor for 30-day postoperative mortality. Considering the expected increase in patients with SO, substantial work is required to optimize bariatric surgery strategies specific to these patients.

N-3 Polyunsaturated Fatty Acids and Their Lipid Mediators as A Potential Immune-Nutritional Intervention: A Molecular and Clinical View in Hepatic Disease and Other Non-Communicable Illnesses

In recent years, the beneficial effect of n-3 polyunsaturated fatty acids (n-3 PUFAs) intake on human health has been widely accepted in the field of immunonutrition. Today, we find a diversity of supplements based on n-3 PUFAs and/or minerals, vitamins and other substances. The main objective of this review is to discuss the importance of n-3 PUFAs and their derivatives on immunity and inflammatory status related to liver disease and other non-communicable illnesses. Based on the burden of liver diseases in 2019, more than two million people die from liver pathologies per year worldwide, because it is the organ most exposed to agents such as viruses, toxins and medications. Consequently, research conducted on n-3 PUFAs for liver disease has been gaining prominence with encouraging results, given that these fatty acids have anti-inflammatory and cytoprotective effects. In addition, it has been described that n-3 PUFAs are converted into a novel species of lipid intermediaries, specialized pro-resolving mediators (SPMs). At specific levels, SPMs improve the termination of inflammation as well as the repairing and regeneration of tissues, but they are deregulated in liver disease. Since evidence is still insufficient to carry out pharmacological trials to benefit the resolution of acute inflammation in non-communicable diseases, there remains a call for continuing preclinical and clinical research to better understand SPM actions and outcomes.

Change in hepatic volume profile in potential live liver donors after lifestyle modification for reduction of hepatic steatosis

PURPOSE

We aimed to evaluate changes in hepatic volume and hemiliver volume percentage in potential liver donors after hepatic steatosis (HS) reduction through lifestyle modification.

METHODS

Fifty liver donor candidates with HS (macrovesicular fat [MaF] ≥ 20%) underwent abdominal computed tomography (CT) and liver biopsy before (baseline) and after (follow-up) lifestyle modification. According to the change in MaF, subjects were classified as group A (MaF reduction ≥ 20%, n = 25), and group B (MaF reduction < 20%, n = 25). The hepatic volume and hemiliver volume percentage were measured using CT volumetric analysis.

RESULTS

Volume percentage of the left hemiliver + S1 (over the whole liver) significantly increased at follow-up in group A (P < 0.001) but not in group B (P = 0.598). The absolute volume change of the right hemiliver and its percentage change from the baseline were significantly greater than those of the left hemiliver + S1 in group A (P < 0.007). There were no significant differences in these values in group B (P = 0.064 and 0.507, respectively). The percentage of subjects that earned the benefit of becoming suitable donors from the change in hepatic volume distribution caused by HS improvement was 52.0% (13/25) and 40.0% (10/25) in group A and group B, respectively. Regarding posthepatectomy liver failure, none was identified in group A after donation, whereas 12% (3/25) was identified in group B.

CONCLUSION

Hepatic volume profile may change considerably in potential liver donors with HS (MaF ≥ 20%) after HS reduction through lifestyle modification. Reevaluation of the hepatic volume is required before liver procurement after lifestyle modification in these subjects.

Effect of preoperative diet regimen on liver size before laparoscopic sleeve gastrectomy in morbidly obese patients

BACKGROUND

Low caloric diet can reduce liver volume; however, there is no consensus regarding preoperative weight reduction before bariatric surgery. This study evaluates the effect of preoperative very-lowcalorie diet (VLCD) in patients undergoing laparoscopic sleeve gastrectomy (LSG).

METHODS

This prospective study included patients scheduled for LSG stratified into two groups, Diet Group (n = 183) who followed a preoperative VLCD regimen for three weeks and underwent assessment of the liver lobes span before and after regimen, and Control Group (n = 138) who underwent sonographic assessment once before surgery and were operated upon without diet. The outcome measures were the impact of preoperative diet on the liver span, intraoperative complications, anthropometric factors affecting the liver span.

RESULTS

Diet regimen resulted in a significant reduction of the right and left lobes. The percentage of the reduction of the left lobe span was significantly higher than that of the right lobe (p < 0.001). Change of the size of the two lobes was correlated positively with weight and body mass index and initial size of both lobes. There was no significant difference between the two groups in the frequency of operative complications.

CONCLUSION

VLCD for three weeks before bariatric surgery effectively reduced liver size. The reduction is more in the left lobe. The changes of both lobes were correlated well with the pre- and post-regimen weight and BMI. It was also positively correlated with the initial size of both lobes.

Efficacy of Intragastric Balloons in the Markers of Metabolic Dysfunction-associated Fatty Liver Disease: Results from Meta-analyses

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease, now renamed metabolic dysfunction-associated fatty liver disease (MAFLD), is common in obese patients. Intragastric balloon (IGB), an obesity management tool with low complication risk, might be used in MAFLD treatment but there is still unexplained heterogeneity in results across studies.

METHODS

We conducted a systematic search of 152 citations published up to September 2020. Meta-analyses, stratified analyses, and meta-regression were performed to evaluate the efficacy of IGB on homeostasis model assessment of insulin resistance (HOMA-IR), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transpeptidase (GGT), and to identify patients most appropriate for IGB therapy.

RESULTS

Thirteen observational studies and one randomized controlled trial met the inclusion criteria (624 participants in total). In the overall estimate, IGB therapy significantly improved the serum markers change from baseline to follow-up [HOMA-IR: 1.56, 95% confidence interval (CI)=1.16-1.95; ALT: 11.53 U/L, 95% CI=7.10-15.96; AST: 6.79 U/L, 95% CI=1.69-11.90; GGT: 10.54 U/L, 95% CI=6.32-14.75]. In the stratified analysis, there were trends among participants with advanced age having less change in HOMA-IR (1.07 vs. 1.82). The improvement of insulin resistance and liver biochemistries with swallowable IGB therapy was no worse than that with endoscopic IGB. Multivariate meta-regression analyses showed that greater HOMA-IR loss was predicted by younger age (p=0.0107). Furthermore, effectiveness on ALT and GGT was predicted by basal ALT (p=0.0004) and GGT (p=0.0026), respectively.

CONCLUSIONS

IGB is effective among the serum markers of MAFLD. Younger patients had a greater decrease of HOMA-IR after IGB therapy.

Changing Trends in Liver Transplantation: Challenges and Solutions

Despite improvements in postliver transplant outcomes through refinements in perioperative management and surgical techniques, several changing trends in liver transplantation have presented challenges. Mortality on the waitlist remains high. In the United States, Europe, and the United Kingdom, there is an increasing need for liver transplantation, primarily as a result of increased incidence of nonalcoholic steatohepatitis-related cirrhosis and cancer indications. Meanwhile, donor suitability has decreased, as donors are often older and have more comorbidities. Despite a mismatch between organ need and availability, many organs are discarded. Notwithstanding this, many solutions have been developed to overcome these challenges. Innovative techniques in allograft preservation, viability assessment, and reconditioning have allowed the use of suboptimal organs with adequate results. Refinements in surgical procedures, including live donor liver transplantations, have increased the organ pool and are decreasing the time and mortality on the waitlist. Despite many challenges, a similar number of solutions and prospects are on the horizon. This review seeks to explore the changing trends and challenges in liver transplantation and highlight possible solutions and future directions.

Factors associated with resolution of type-2 diabetes mellitus after sleeve gastrectomy in obese adults

Many bariatric procedures are more effective for improving type-2 diabetes mellitus (T2DM) than conventional pharmacotherapy. The current research evaluated factors linked to complete and partial remission or improvement of T2DM after laparoscopic sleeve gastrectomy (LSG). The current prospective study included all diabetic patients who were submitted LSG between January 2015 and June 2018 and completed a 2-year follow-up period. Patients were assessed at baseline and 2 years after LSG. This work comprised of 226 diabetic cases. Two years after LSG, 86 patients (38.1%) achieved complete remission of DM, and 24 (10.6%) reached partial remission. Only 14 patients (6.2%) showed no change in their diabetic status. On univariate analysis, age ≤ 45 years, duration of diabetes ≤ 5 years, use of a single oral antidiabetic, HbA1c ≤ 6.5%, HOMA-IR ≤ 4.6, C-peptide > 2.72 ng/mL, and BMI ≤ 40 kg/m² predicted complete remission. The independent predictors of complete remission were age ≤ 45 years, duration of diabetes ≤ 5 years, use of a single oral antidiabetic, HOMA-IR ≤ 4.6, and C-peptide > 2.72 ng/mL. A combined marker of young age, short duration of DM, and low HOMA-IR predicted complete remission with sensitivity 93% and specificity 82%. Independent predictors of complete remission of T2DM after LSG were younger age, shorter duration, single oral antidiabetic, lower HOMA-IR, and higher C-peptide.

Assessment of Protein Intake in the First Three Months after Sleeve Gastrectomy in Patients with Severe Obesity

An adequate protein intake prevents the loss of fat-free mass during weight loss. Laparoscopic sleeve gastrectomy (SG) jeopardizes protein intake due to post-operative dietary restriction and intolerance to protein-rich foods. The purpose of this study is to evaluate protein intake in the first three months after SG. We evaluated, 1 month and 3 months after surgery, 47 consecutive patients treated with SG. Protein intake, both from foods and from protein supplementation, was assessed through a weekly dietary record. Patients consumed 30.0 ± 10.2 g of protein/day on average from foods in the first month, with a significant increase to 34.9 ± 4.8 g of protein/day in the third month (p = 0.003). The use of protein supplementation significantly increased total protein intake to 42.3 ± 15.9 g protein/day (p < 0.001) in the first month and to 39.6 ± 14.2 g of protein/day (p = 0.002) in the third one. Compliance with supplement consumption was 63.8% in the first month and only 21.3% in the third month. In conclusion, both one and three months after SG, protein intake from foods was not sufficient. The use of modular supplements seems to have a significant impact on protein intake, but nevertheless it remains lower than recommended.

Computed Tomography Assessment of Fat Distribution and Staple-Line Leak Risk After Sleeve Gastrectomy

PURPOSE

Sleeve gastrectomy (SG) has become the most frequent bariatric procedure and staple-line leak represents its most feared complication. Visceral obesity, a core component of the metabolic syndrome, has been associated with worst postoperative outcomes after various abdominal surgical procedures, and can be estimated by computed tomography (CT). The aim of this study was to assess the impact of radiologically determined visceral obesity in the risk of staple-line leak after SG.

MATERIAL AND METHODS

A retrospective analysis of a prospective database was performed in consecutive patients undergoing SG. Several anthropometric variables were measured on a preoperative CT scan. Multivariate analysis was performed to determine preoperative risk factors for staple-line leak.

RESULTS

During the study period, 377 patients were included in the analysis. The median BMI was 39.7 kg/m² (36.5-43.5) and 8 patients (2.1%) presented a gastric leak. After multivariate analysis, visceral obesity defined by visceral fat area (VFA)/body surface area (BSA) ≥ 85 cm²/m² was the only independent predictive factor for gastric leak (OR = 5312).

CONCLUSION

CT scan-assessed visceral obesity defined by a VFA/BSA ratio ≥ 85 cm²/m² is associated with an increased risk of gastric leak after SG. Preoperatively radiological examination in patients suspected of visceral obesity would be useful to optimize preoperative management.

Body Composition Changes Following a Very-Low-Calorie Pre-Operative Diet in Patients Undergoing Bariatric Surgery

BACKGROUND

Fatty liver in obese patients increases the technical difficulty of bariatric surgery. Pre-operative weight loss with a very-low-calorie diet (VLCD) is commonly used to facilitate surgery. Few studies have quantified the systemic effect of rapid pre-operative weight loss on body composition. The objective of this study is to evaluate body composition changes in bariatric surgery patients undergoing a VLCD.

METHODS

Body composition assessments were performed between August 2017 and January 2019 using dual-energy X-ray absorptiometry immediately before and after a 2-week VLCD at St Vincent's Hospital Melbourne. Data collected prospectively pre- and post-VLCD included total body weight, excess body weight, body mass index (BMI), lean body mass (LBM), fat mass (FM) and bone mineral content (BMC). The pre- and post-operative results were compared.

RESULTS

Forty-four patients completed both the 2-week VLCD and body composition assessments. Following a 2-week VLCD, patients lost a mean of 4.5 kg (range - 0.3 to 9.5) in a total body weight and 8.8% (range - 0.9 to 17.1) of excess body weight, with a mean reduction in body mass index of 1.6 kg/m² (range - 0.2 to 3.1). Loss of LBM was 2.8 kg and was significantly greater than loss of FM, 1.7 kg (p < 0.05). BMC changes were insignificant.

CONCLUSION

A VLCD is an effective tool for pre-operative weight reduction. In this cohort, a large amount of the total weight loss was attributed to a loss of lean body mass. The impact of significant lean body mass loss and its relationship to short- and long-term health outcomes warrants further assessment.

Beneficial effects of the ketogenic diet on nonalcoholic fatty liver disease: A comprehensive review of the literature

Nonalcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease, characterized by hepatic fat accumulation and possible development of inflammation, fibrosis, and cancer. The ketogenic diet (KD), with its drastic carbohydrate reduction, is a now popular weight loss intervention, despite safety concerns on a possible association with fatty liver. However, KDs were also reported to be beneficial on hepatic pathology, with ketone bodies recently proposed as effective modulators of inflammation and fibrosis. If the beneficial impact of weight loss on NAFLD is established, less is known on the effect of macronutrient distribution on such outcome. In a hypocaloric regimen, the latter seems not to be crucial, whereas at higher calorie intake, macronutrient ratio and, theoretically, ketosis, may become important. KDs could positively impact NAFLD for their very low carbohydrate content, and whether ketosis plays an additional role is unknown. Indeed, several mechanisms may directly link ketosis and NAFLD improvement, and elucidating these aspects would pave the way for new therapeutic strategies. We herein aimed at providing an accurate revision of current literature on KDs and NAFLD, focusing on clinical evidence, metabolic pathways involved, and strict categorization of dietary interventions.

Hyposalivation is prevalent in bariatric patients but improves after surgery

BACKGROUND

Obesity and type 2 diabetes can be associated with poor oral health. This can be because of hyposalivation leading to chronic oral inflammation (OI) and periodontal disease.

OBJECTIVE

To assess the prevalence of hyposalivation and OI in individuals undergoing Roux-en-Y gastric bypass (RYGB) and determine the relationship with metabolic and anthropometric parameters before and after RYGB.

SETTING

University hospital in Canada.

METHODS

This was a cross-sectional and prospective cohort study of 59 patients undergoing RYGB from September 2015 to December 2019. Anthropometric, biochemical, and oral measurements were taken before surgery and 1 and 6 months post RYGB. Oral parameters included salivary flow rate and neutrophil count as marker of OI.

RESULTS

Fifty-nine patients were enrolled with 29 completing this study. At baseline, the median age was 47 years and body mass index was 46.5 kg/m², 52 (88.1%) were female and 14 individuals (23.7%) had type 2 diabetes; 54.2% (n = 32) of patients had hyposalivation and 13.6% (n = 8) had high neutrophil count. Patients with hyposalivation had significantly higher fasting glucose (5.7 mmol/L) compared with those without hyposalivation (5.2 mmol/L) but no difference was found between high versus low neutrophil count. At 6 months post RYGB, all variables except oral neutrophil count significantly improved. Hyposalivation persisted in 7 (24%) individuals.

CONCLUSIONS

In our bariatric patients, more than half the patients had hyposalivation before RYGB and this was associated with higher fasting glucose. Hyposalivation improved post RYGB in parallel with improvements in metabolic parameters but there was no change in OI. Increased salivation may reduce the risk of periodontal disease.

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.

Improving Compliance with Very Low Energy Diets (VLEDs) Prior to Bariatric Surgery-a Randomised Controlled Trial of Two Formulations

INTRODUCTION

Preoperative very low energy diets (VLEDs) improve access during bariatric surgery. Compliance with traditional VLED is variable, mainly due to gastrointestinal side effects. Formulite™ is a new formulation of VLED, with higher protein, soluble fibre and probiotics.

AIMS

To compare traditional VLED (Optifast™) with the new VLED (Formulite™) and assess compliance, weight loss, satisfaction, side effects and surgical access.

METHODS

This was a randomised double-blinded study involving patients scheduled for bariatric surgery. The primary outcome was compliance, assessed by urinary ketone concentration and proportion of patients in ketosis at 2 weeks. Secondary outcomes were weight loss, satisfaction and patient reported outcomes, gastrointestinal side effects and operative conditions.

RESULTS

There were 69 participants: 35 in the Formulite™ group and 34 in the Optifast™ group. Ketosis at 2 weeks was achieved in both groups (88.5% vs 83.3%, Formulite™ vs. Optifast™, p = 0.602). Urinary ketones were higher with Formulite™ (1.5 vs 15 mmol/L, p = 0.030). Total body weight loss percentage, hunger and operative conditions were similar in both groups. Formulite™ produced less flatulence (score 3 vs 2, p = 0.010) and emotional eating (score 2 vs 1, p = 0.037); however, Optifast™ ranked higher in terms of taste (score 4 vs 3, p = 0.001) and overall satisfaction (score 5 vs 7, p = 0.011).

CONCLUSIONS

Compliance over 2 weeks was high in both VLEDs with most subjects achieving ketosis. Overall satisfaction was moderately high, although variable. Whilst Formulite™ is a viable alternative to Optifast™, better formulations of VLED that addresses key adverse effects, whilst achieving ketosis, would be of significant value.

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.

Negative Energy Balance Induced by Exercise or Diet: Effects on Visceral Adipose Tissue and Liver Fat

The indisputable association between visceral adipose tissue (VAT) and cardiometabolic risk makes it a primary target for lifestyle-based strategies designed to prevent or manage health risk. Substantive evidence also confirms that liver fat (LF) is positively associated with increased health risk and that reduction is associated with an improved metabolic profile. The independent associations between reductions in VAT, LF, and cardiometabolic risk is less clear. In this narrative review, we summarize the evidence indicating whether a negative energy balance induced by either an increase in energy expenditure (aerobic exercise) or a decrease in energy intake (hypocaloric diet) are effective strategies for reducing both VAT and LF. Consideration will be given to whether a dose-response relationship exists between the negative energy balance induced by exercise or diet and reduction in either VAT or LF. We conclude with recommendations that will help fill gaps in knowledge with respect to lifestyle-based strategies designed to reduce VAT and LF.

Nonalcoholic Fatty Liver Disease in Adults: Current Concepts in Etiology, Outcomes, and Management

Nonalcoholic fatty liver disease (NAFLD) is a spectrum of disease, extending from simple steatosis to inflammation and fibrosis with a significant risk for the development of cirrhosis. It is highly prevalent and is associated with significant adverse outcomes both through liver-specific morbidity and mortality but, perhaps more important, through adverse cardiovascular and metabolic outcomes. It is closely associated with type 2 diabetes and obesity, and both of these conditions drive progressive disease toward the more advanced stages. The mechanisms that govern hepatic lipid accumulation and the predisposition to inflammation and fibrosis are still not fully understood but reflect a complex interplay between metabolic target tissues including adipose and skeletal muscle, and immune and inflammatory cells. The ability to make an accurate assessment of disease stage (that relates to clinical outcome) can also be challenging. While liver biopsy is still regarded as the gold-standard investigative tool, there is an extensive literature on the search for novel noninvasive biomarkers and imaging modalities that aim to accurately reflect the stage of underlying disease. Finally, although no therapies are currently licensed for the treatment of NAFLD, there are interventions that appear to have proven efficacy in randomized controlled trials as well as an extensive emerging therapeutic landscape of new agents that target many of the fundamental pathophysiological processes that drive NAFLD. It is highly likely that over the next few years, new treatments with a specific license for the treatment of NAFLD will become available.

Short-term Dietary Interventions for the Management of Nonalcoholic Fatty Liver

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) affects millions of individuals on a global scale and currently no gold standard treatment exists. The risk of developing NAFLD is considerably higher with increasing body mass index. Consequently, weight loss should be recommended to all overweight patients with fatty liver. However, lifestyle interventions, irrespective of weight status, may also influence the condition. The aim herein is to present examples of short-term interventions which assess direct effects of dietary-related components on hepatic steatosis.

METHODS

This review includes studies with short-term dietary-related interventions of up to 16 weeks that evaluate their efficacy in reducing intrahepatic lipid contents (hepatic steatosis). This review primarily focuses on the three main macronutrients: dietary carbohydrates, fats and proteins.

RESULTS

High saturated fat intake and high consumption of carbohydrates, particularly from simple sugars such as fructose are reported as risk factors for hepatic steatosis. Overall, shortterm hypocaloric diets have shown beneficial effects in reducing intrahepatic lipid contents. Macronutrient manipulations such as carbohydrate restriction as well as the consumption of unsaturated fatty acids are also reported to have efficacious effects.

CONCLUSION

This review highlights the different dietary interventions that can influence hepatic steatosis in the short term, illustrating both pro and anti-steatotic effects.

Effects of Two Preoperatory Weight Loss Diets on Hepatic Volume, Metabolic Parameters, and Surgical Complications in Morbid Obese Bariatric Surgery Candidates: a Randomized Clinical Trial

OBJECTIVE

To assess which type of preoperative dietary strategy is most effective in reducing liver volume and assessing its influence on different biochemical parameters and on surgical complications in individuals undergoing bariatric surgery.

METHODS

Parallel randomized trial comparing the effect of a very low calorie diet (VLCD) and a low calorie diet (LCD) for a period of 21 days before surgery on hepatic volume, anthropometric and biochemical parameters. Compliance and tolerance to the diets, surgical complications, and hospital stay were also determined.

RESULTS

Eighty-six morbid obese participants undergoing bariatric surgery were randomized. The hepatic volume was significantly reduced in both intervention groups, but no differences in changes between groups were detected. The reduction in the hepatic volume was higher in those patients with a baseline hepatic volume > 3 L compared to those with < 3 L (adjusted P value < 0.001). The percentages of total weight lost were 5.8 and 4.2% (adjusted P value = 0.004) for participants on the VLCD and LCD, respectively. There were no differences between groups for any of the biochemical parameters analyzed, nor in the number of surgical complications nor the length of hospital stay. Adherence to the diet was good; nevertheless, participants in the VLCD intervention showed worse tolerance.

CONCLUSIONS

In subjects with morbid obesity undergoing bariatric surgery, compared to a LCD, a preoperative 21-day intervention with VLCD is more effective in terms of reducing total body weight but not in terms of reducing the liver volume. Both types of preoperative diets have similar effects on clinical biochemical parameters, rate of surgical complications, and hospital length stay.

Short-term Preoperative Diet Decreases Bleeding After Partial Hepatectomy: Results From a Multi-institutional Randomized Controlled Trial

BACKGROUND

Our previous case series suggested that a 1-week, low-calorie and low-fat diet was associated with decreased intraoperative blood loss in patients undergoing liver surgery.

OBJECTIVE

The current study evaluates the effect of this diet in a randomized controlled trial.

METHODS

We randomly assigned 60 patients with a body mass index ≥25 kg/m(2) to no special diet or an 800-kcal, 20 g fat, and 70 g protein diet for 1 week before liver resection. Surgeons were blinded to diet assignment. Hepatic glycogen stores were evaluated using periodic acid Schiff (PAS) stains.

RESULTS

Ninety four percent of the patients complied with the diet. The diet group consumed fewer daily total calories (807 vs 1968 kcal, P < 0.001) and fat (21 vs 86 g, P < 0.001) than the no diet group. Intraoperative blood loss was less in the diet group: mean blood loss 452 vs 863 mL (P = 0.021). There was a trend towards decreased transfusion in the diet group (138 vs 322 mL, P = 0.06). The surgeon judged the liver to be easier to manipulate in the diet group: 1.86 versus 2.90, P = 0.004. Complication rate (20% vs 17%), length of stay (median 5 vs 4 days) and mortality did not differ between groups. There was no difference in hepatic steatosis between groups. There was less glycogen in hepatocytes in the diet group (PAS stain score 1.61 vs 2.46, P < 0.0001).

CONCLUSIONS

A short-course, low-fat, and low-calorie diet significantly decreases bleeding and makes the liver easier to manipulate in hepatic surgery.

The Efficacy of Energy-Restricted Diets in Achieving Preoperative Weight Loss for Bariatric Patients: a Systematic Review

In bariatric practice, a preoperative weight loss of at least 5% is recommended. However, the hypocaloric diets prescribed vary and no consensus exists. This study examined the efficacy of preoperative diets in achieving 5% weight loss. From a systematic literature search, eight randomised controlled trials (n = 862) were identified. Half of the trials used a "very-low-calorie diet" whilst the rest employed a "low-calorie diet". Only five diets achieved ≥ 5% weight loss over varying durations and energy intakes. By inference, compliance with a 700-1050 kcal (2929-4393 kJ) diet, consisting of moderate carbohydrate, high protein and low/moderate fat, for 3 weeks is likely to achieve 5% weight loss. A low-carbohydrate diet (< 20 g/day) may achieve this target within a shorter duration. Additional research is required to validate these conclusions.

Dietary Management in the Immediate Preoperative Period of Bariatric Surgery: a National Overview : Bariatric Preoperative Diets

BACKGROUND

Although widely applied, there is no consensus about the characteristics of the diets prescribed in the immediate preoperative period of bariatric surgery (BS). The objective of this study was to perform a survey on preoperative dietary management in BS centers.

METHODS

This was a cross-sectional study with BS Brazilian centers. Only BS centers with certificate of excellence by Surgical Review Corporation were included. An electronic questionnaire was applied to assess details about the dietary management in the immediate preoperative period of BS.

RESULTS

Of the 15 centers invited, 80% (n = 12) answered the questionnaire. Preoperative weight loss was required to patients in all 12 centers. For 8.3% (n = 1), this request was applied to all patients; 91.7% (n = 11) of the centers requested weight loss in specific cases. Ten (83.3%) centers prescribed restrictive diets; none of these adopted a standard dietary protocol. The caloric value of the diets ranged from 800 to 2000 kcal/day. The duration of the diet ranged from 10 to 20 days in 40% (n = 4) of the centers and from 20 to 90 days in 60% (n = 6) of the centers. Dietary prescription was based on team consensus in 100% (n = 12) of the centers. In 33.3% (n = 4) of the centers, scientific evidence supporting dietary prescription was cited.

CONCLUSION

This study identified the frequent practice of requesting preoperative weight loss and the diversity of diets used in the immediate preoperative period by Brazilian BS centers. Future guideline proposal is needed on preoperative BS diets.

A 4-Week Preoperative Ketogenic Micronutrient-Enriched Diet Is Effective in Reducing Body Weight, Left Hepatic Lobe Volume, and Micronutrient Deficiencies in Patients Undergoing Bariatric Surgery: a Prospective Pilot Study

BACKGROUND

Before bariatric surgery (BS), moderate weight loss, left hepatic lobe volume reduction, and micronutrient deficiency (MD) identification and correction are desirable.

OBJECTIVES

The objective of this study was to assess the safety and the effectiveness of a 4-week preoperative ketogenic micronutrient-enriched diet (KMED) in reducing body weight (BW), left hepatic lobe volume, and correcting MD in patients scheduled for BS.

MATERIALS AND METHODS

In this prospective pilot study, a cohort of morbidly obese patients (n = 27, 17 females, 10 males) with a mean body mass index (BMI) of 45.2 kg/m² scheduled for BS underwent a 4-week preoperative KMED. Their BW, BMI, fat mass (FM), fat-free mass (FFM), resting metabolic rate (RMR), left hepatic lobe volume, micronutrient status, and biochemical and metabolic patterns were measured before and after the 4-week KMED. Patient compliance was assessed by validated questionnaires (3-day estimated food records and 72-h recall). Qualitative methods (5-point Likert questionnaire) were used to measure diet acceptability and side effects.

RESULTS

All patients completed the study. We observed highly significant decreases in BW (- 10.3%, p < 0.001, in males; - 8.2%, p < 0.001, in females), left hepatic lobe volume (- 19.8%, p < 0.001), and an amelioration of patient micronutrient status. All patients showed a high frequency of acceptability and compliance in following the diet. No adverse side effect was reported.

CONCLUSION

This study demonstrates that a 4-week preoperative KMED is safe and effective in reducing BW, left hepatic lobe volume, and correcting MD in obese patients scheduled for BS.