Studies have shown that a drug called fexaramine triggers a physiological reaction in mice akin to what happens after the animals eat a big meal. This is releasing bile acids into the intestines to digest food. Obese mice on a high-fat diet given a daily dose of fexaramine for five weeks stopped gaining weight.
In terms of what is happening biochemically, fexaramine activates the farnesoid X receptor (FXR) that normally switches on at the beginning of a meal.
Study coauthor Ronald Evans, director of the Gene Expression Laboratory at the Salk Institute for Biological Studies in La Jolla, California spoke about the findings in a research brief:
“This pill is like an imaginary meal. It sends out the same signals that normally happen when you eat a lot of food, so the body starts clearing out space to store it. But there are no calories and no change in appetite.”
In addition to helping the animals lose weight, fexaramine seemed to lower blood sugar and cholesterol levels and increased the amount of brown — or “good” — fat. Brown adipose tissue (is one of two types of fat or adipose tissue (the other being white adipose tissue, or white fat) found in mammals. Brown fat is significant because lean people tend to have more brown fat than overweight or obese people — and that when stimulated it can burn calories.
Furthermore, because the drug does not enter the bloodstream, fexaramine may have fewer side effects compared with other existing weight-loss medications. The researchers are now working to move the drug into human trials. A word of caution, though. Studies in animals do not necessarily lead to the same effects in people. Moreover, such a medication as a “fat burning pill” would require rigorous and extensive safety trials over the course of several years.
The findings have been published in Nature Medicine. The paper is titled “Intestinal FXR agonism promotes adipose tissue browning and reduces obesity and insulin resistance.”
