Plasma concentration of gastrointestinal hormones and subjective appetite ratings after diet or bariatric surgery: 1-year results from the DISGAP study

Objective: Long-term weight loss outcomes are contrasting between bariatric surgery and dietary restriction alone. This is the first study to investigate changes in gastrointestinal (GI) hormones involved in appetite regulation, and subjective appetite feelings, at 1-year follow-up, after initial weight loss induced by a very-low energy (VLED) alone (controls), or with bariatric surgery. Methods: Patients scheduled for Sleeve Gastrectomy (SG) (n = 19) or Roux-en-Y gastric Bypass (RYGB) (n = 19), and controls (n = 16) were recruited. All groups underwent 10 weeks of a VLED (initial phase), followed by a 9-month maintenance phase. Body weight/composition, plasma concentrations of ghrelin, glucagon-like peptide 1 (GLP-1), peptide YY (PYY), cholecystokinin (CCK), and appetite ratings were measured before and after a meal, at baseline, week 11(W11), and 1Y follow-up. Results: Participants who completed all three follow ups were included in the analysis. Initial changes in body weight/composition were comparable across groups. SG (n = 11) and RYGB (n = 12) continued to lose weight from W11 to 1Y, whereas controls (n = 12) had regained weight. Postprandial GLP-1 increased over time post bariatric surgery and remained unchanged and lower in controls. Postprandial PYY increased in all groups, but greatest post-RYGB. Basal ghrelin decreased over time post-SG, while a small or marked increase was seen after RYGB and diet, respectively, with the control group exhibiting the greatest basal and postprandial concentrations at 1Y. A reduction in basal and postprandial CCK was seen in controls at 1Y, while no changes were observed post-bariatric surgery. Overall, small changes in subjective appetite ratings were seen over time. Conclusion: Weight change at 1Y follow up after SG and RYGB is followed by a GI hormone profile favoring a lower drive to eat and increased satiety. The opposite is seen 1Y after WL induced by dietary restriction alone. Clinical trial registration: clinicaltrials.gov NCT04051190.