Scientists from a group of international institutions have developed a new type of weight loss pill called fexaramine that tricks the body into thinking it has consumed calories, which causes it to burn fat.
The weight-loss compound, which has so far only been tested on mice, doesn't dissolve into the blood like caffeine-based diet drugs or appetite suppressants, and instead remains in the intestines, causing fewer side effects.
The researchers' findings, which showed that fexaramine has been able to stop weight gain, control blood sugar, lower cholesterol and minimise inflammation in mice, are detailed in the latest issue of Nature Medicine.
Ronald Evans, director of the Gene Expression Laboratory at Salk Institute for Biological Studies and senior author of the new paper, has been researching the farensoid X receptor (FXR) for almost 20 years.
The farensoid X receptor (FXR)
FXR is a protein that plays a role in how the body releases bile acids from the liver, digests food and stores fats and sugars.
The protein controls when bile acids are released for digestion, and is also in charge of changing blood sugar levels and dictating when the body burns fat, in preparation for an incoming meal.
"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," said Evans. "But there are no calories and no change in appetite."
At the moment, there are systemic drugs on the market to treat obesity, diabetes, liver disease and other metabolic conditions that work by activating FXR, however these drugs affect several organs at once and cause numerous side effects.
So Evans decided to see what would happen if FXR were only switched on in the intestines, rather than the rest of the body.
Decrease in cholesterol and blood sugar levels
Together with his team, he developed fexaramine, and when the pill was given to obese mice once a day for five weeks, the mice began losing weight, and their blood sugar and cholesterol levels dropped.
Not only that, but a rise in body temperature was also seen in the mice (a common signal that metabolism is ramping up in the body) and deposits of white fat in their bodies converted to become a healthier, energy-burning form of beige fat instead.
As fexaramine doesn't reach the bloodstream, the researchers say that it is safer than other FXR-targeting drugs.
Their next step is to set up human clinical trials to test the pill's effectiveness on treating metabolic disease and obesity, so it could still be at least two years before the drug receives FDA approval.
The research bodies involved in the study include the Salk Institute for Biological Studies; University of Michigan; University of California, San Diego; University of Sydney and École Polytechnique Fédérale de Lausanne.