Weight regain in patients undergoing gastric bypass; associations with objective measures of eating behaviours

Abstract

Gastric bypass surgery is a successful treatment for obesity and the associated comorbidities. The mechanisms underlying weight loss and weight regain following gastric bypass are complex and poorly understood, however may be linked to changes in eating behaviour. The aim of this thesis was to investigate eating related behaviours in dividuals living with obesity and undergoing gastric bypass surgery up to 60-monthspost-surgery. The secondary aim was to examine the associations between eating behaviour with energy intake, lean mass and body mass index and the associations between the early changes in eating behaviours and weight loss at 60-momths. This work used objective measures of energy intake and eating behaviours, with the current evidence based largely based on self-reported measures which are notoriously prone to underreporting. Individuals living with obesity had a similar energy intake to those without obesity, with no differences in dietary energy density, relative intake (%EI)from macronutrients or in eating behaviours. The positive association between eating frequency and energy intake may suggest a potential role in the development of obesity. The positive association between lean mass and energy intake and behaviours relating to eating rate and eating occasion size may further suggest a role of lean mass in driving food intake and obesity. After surgery, there was a reduction in energy intake in patients undergoing gastric bypass at 60-months, along with a decrease in dietary energy density and an increase in eating frequency. There was no change in the intake of macronutrients or in the rate or size of eating occasions, although patients did consume a higher energy intake in the evening compared to the morning at 60-months.Early changes in behaviour may be used to identify those at highest risk of insufficient weight loss or weight regain following gastric bypass, with a decrease in eating occasion size potentially important as a strategy to reduce energy intake. An early change in post-prandial glicentin response may be able to predict those at risk of suboptimal clinical responses, insufficient weight loss and weight regain. These responses may also be attributed to the presence of disordered eating behaviours after surgery (binge eating and grazing) and an increase in psychological concerns (loss-of control). Greater psychological support and earlier identification of modifiable eating behaviours could lead to more effective management of patients undergoing gastric bypass and minimise the risk of insufficient weight loss or weight regain developing

Date of Award	Feb 2025
Original language	English
Sponsors	DfE (US-Ireland R&D Partnership)
Supervisor	Ruth Price (Supervisor), Chris Gill (Supervisor), Maeve Kerr (Supervisor), Barbara Livingstone (Supervisor) & Julie Sittlington (Supervisor)