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

Abstract

Background Lack of robust research methodology for assessing ingestive behaviour has impeded clarification of the mediators of food intake following gastric bypass (GBP) surgery. Objective To evaluate changes in directly measured 24hr energy intake (EI), energy density (ED) (primary outcomes), eating patterns and food preferences (secondary outcomes) in patients and time matched weight-stable comparator participants. Design Patients (n = 31,77% female, BMI 45.5±1.3) and comparators (n = 32, 47% female, BMI 27.2±0.8) were assessed for 36hr under fully residential conditions at baseline (1-mo pre-surgery) and at 3- and 12-mo post-surgery. Participants had ad libitum access to a personalised 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 dual-energy x-ray absorptiometry. Results In the comparator group there was an increase in relative fat intake at 3-mo post-surgery, otherwise no changes were observed in food intake or body composition. At 12-mo post-surgery, patients lost 27.7±1.6% of initial body weight (p<0.001). The decline in EI at 3-mo post-surgery (-44% from baseline, P<0001)) 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 pre-surgery 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 was not matched by reduced intake of these foods. Patients with the greatest reduction in ED post-surgery reduced both EI and preference for sweet foods. Conclusion 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. Clinical Trial Registry Number: NCT03113305 (ClinicalTrials.gov)

Tripeptide gut hormone infusion does not alter food preferences or sweet taste function in volunteers with obesity and prediabetes/diabetes but promotes restraint eating: A secondary analysis of a randomized single‐blind placebo‐controlled study

“…Targeting direct eating behaviour, Nielsen et al and Livingstone et al demonstrated that food preferences do not consistently change post-RYGB in their participants, but in those where they do, it may result in additional weight loss. [36][37][38] It is therefore conceivable that sweet taste function may also change in some but not all patients post-RYGB, which may potentially drive the shifts away from palatable food and aid weight loss in a select few.…”

“…Studies using self‐reported and subjective methods which fundamentally rely on accurate reporting from participants often demonstrate changes in taste and preference for low‐calorie dense food, but these findings are not consistently replicated when direct measures of eating behaviour in supervised settings are used. Targeting direct eating behaviour, Nielsen et al and Livingstone et al demonstrated that food preferences do not consistently change post‐RYGB in their participants, but in those where they do, it may result in additional weight loss 36‐38 . It is therefore conceivable that sweet taste function may also change in some but not all patients post‐RYGB, which may potentially drive the shifts away from palatable food and aid weight loss in a select few.…”

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

“…Although it was beyond the scope of the present study to explain its causality, the small changes in nutrient composition and diet quality could indicate that dietary intake in the present study was mainly altered by the reduction of the amount of food intake and not in the type of food consumed, as reported by several other studies. 52,53 However, there are several other factors to take into account, such as nutritional counseling and education about healthy food choices, food intolerances and changes in taste, food preferences, and food reward in the brain.…”

Metabolic adaptation following gastric bypass surgery: Results from a 2-year observational study.

“…The hypothesis for this paper was tested as a secondary hypothesis within a wider study investigating changes in energy intake following GBP, which is described in detail elsewhere (14,15). Owing to the novel study protocol, the sample size was estimated from the patient population recruited for a randomised controlled trial (16) that detected signi cant differences in self-reported energy intake between Vertical Banded Gastrectomy (VBG (n = 7) and GBP (n = 9) participants at 6 years post-surgery.…”