High-fat foods actually change the bacteria in your gut and make it so that we’re unable to detect the sensation that we’re full. A team of scientists took 50 rats and fed some of them balanced diets with proteins, fats, and carbohydrates. Others had diets with a higher fat content, which had previously been proven to cause weight gain. The rats were able to eat as much as they pleased.
Scientists monitored the rats for two months. The rats on the high-fat diet ate more, and subsequently gained enough weight to be 25% larger. In addition to their size, the gut microbiome in the rats on the high-fat diet had shifted. Some bacteria populations grew while others were eliminated. This bacterial imbalance damaged the vagus nerve, which is responsible for signaling to the brain for when we’re full. When the vagus nerve is broken, the brain cannot hear all the complete information about the gut feeling full. And as a result, the rats on the high-fat diet kept eating—even beyond the point where they were satiated.
The gut-brain communication in humans is very similar to rodents. An unbalanced diet could lead to an unbalanced gut-microbiome, which could lead to a damaged vagus nerve. When we gain weight by eating a lot of fats or sugars, we may decide to cut them out of our diet. But the damage may already be done. http://www.delta-optimist.com/opinion/blogs/deltabc-1.983313/blog-rats-fat-and-your-brain-1.1998607