A new study, led by scientists at Imperial College London has found that gastric bypass surgery alters people’s food preferences so that they eat less high fat food.
The findings, published in the American Journal of Physiology – Regulatory, Integrative, and Comparative Physiology, suggest a new mechanism by which some types of bariatric surgery lead to long-term weight loss. The study involved data from human trials as well as experiments using rats. The researchers used data from 16 participants in a study in which obese people were randomly assigned either gastric bypass surgery or vertical-banded gastroplasty, in which the stomach volume is reduced but no part of the intestine is bypassed. The participants who had gastric bypass had a smaller proportion of fat in their diet six years after surgery, based on questionnaire responses. In the rat experiments, rats given gastric bypass surgery were compared with rats that were given a sham operation. Rats that had gastric bypass surgery ate less food in total, but they specifically ate less high fat food and more low fat food. Levels of the satiety-promoting hormones GLP-1 and PYY were higher after feeding in the gastric bypass rats compared with sham-operated rats, suggesting a possible mechanism for the changes in food preferences. The team plans to study the role of these hormones further to see if it might be possible to mimic the effects of gastric bypass without using surgery. The research was funded by the Imperial Comprehensive Biomedical Research Centre.
