Know someone who’s lost a bunch of weight? Well, studies have repeatedly show that people are very likely to regain lost weight within two years of losing it. A new study published in the International Journal of Obesity suggests that, after being obese for awhile, a persons gastrointestinal hormones become less sensitive, and therefore less able to detect when you’re full.
Researchers at the University of Adelaide tested their theory on a three groups of mice. The control group ate normal laboratory food, another ate a high-fat diet, and a third ate a high-fat diet for half of the study period before going back to a regular diet for the rest of the time. The researchers then killed the mice, but preserved their intact stomach and oesophagus, in order to test the responsiveness of nerves that signal satiety to the brain.
Mice on the high fat diet gained the most weight. The mice who switch diets halfway through, however, lost some weight when they switched their diet, but gained it all back by the end of the study, owing to the fact that they ended up doubling down on eating their new, healthier food.
Moreover, sensitivity to satiety in their gut receptors stayed dull after they switched to a healthy diet, suggesting that once obesity damages gut receptions, there’s no fixing the problem.