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

Aims
To investigate whether the elevation in the post-prandial concentrations of the gut hormones Glucagon-Like Peptide-1 (GLP-1), Oxyntomodulin (OXM) and Peptide YY (PYY), accounts for the beneficial changes in food preferences, sweet taste function and eating behaviour after RYGB.

Materials and Methods
This was a secondary analysis of a randomised single-blinded study where we infused GLP-1, OXM, PYY (GOP) or 0.9% Saline subcutaneously for 4 weeks in 24 subjects with obesity and pre-diabetes/diabetes, to replicate their peak post-prandial concentrations, as measured at 1-month in a matched RYGB cohort (ClinicalTrials.gov NCT01945840). A 4-day food diary and validated eating behaviour questionnaires were completed. Sweet taste detection was measured using the method of constant stimuli. Correct sucrose identification (corrected hit rates) was recorded, and sweet taste detection thresholds (EC50s) were derived from concentration curves. The intensity and consummatory reward value of sweet taste were assessed using the generalised Labelled Magnitude Scale.

Results
Mean daily energy intake was reduced by 27% with GOP but no significant changes in food preferences were observed, whereas a reduction in fat and increase in protein intake were seen post-RYGB. There was no change in corrected hit rates or detection thresholds for sucrose detection following GOP. Additionally, GOP did not alter the intensity or consummatory reward value of sweet taste. A significant reduction in restraint eating, comparable to the RYGB group was observed with GOP.

Conclusion
The elevation in plasma GOP concentrations after RYGB, are unlikely to mediate changes in food preferences and sweet taste function after surgery but may promote restraint eating.