We’ve all done it: kept on eating when we’ve already had enough. But some people do it all the time because their brains don’t seem to register that they’ve overeaten—and it can lead to obesity. Now researchers believe they know why: A high-fat diet can cripple fullness receptors in the brain.
When you eat, your fat reserves release a hormone called leptin that travels to your brain. When enough leptin reaches the hypothalamus area of the brain, it signals to the body that your stomach is full. Researchers have known for a while that although obese people have normal levels of leptin, their bodies don’t register the “full” signal; the problem is called leptin resistance. But until now, scientists didn’t know why. Find out the 50 foods nutritionists never eat, so you shouldn’t either.
A team of researchers led by research scientist Rafi Mazor at the department of bioengineering at the University of California, San Diego, set out to discover the reason; their results have been published in Science Translational Medicine. The team fed mice a high-fat diet, tracking their leptin levels and how the mice’s brains responded. They discovered that the high-fat diet also encouraged the production of an enzyme called MMP-2. This enzyme altered the surface of the brain cells in the hypothalamus—it clipped the cells so that leptin couldn’t bind to receptors. This meant the neurons couldn’t sound the alarm when the stomach became full.
The scientists then genetically modified a group of mice so that they didn’t produce MMP-2. They found that despite the high-fat diet, these mice remained sensitive to leptin and their weight remained stable. The scientists found that when MMP-2 was blocked, the leptin could bind successfully to the receptors and send the “full” signals, according to Science Daily.
The bottom line is that a high-fat diet actually damages the body’s ability to send signals that the stomach is full. This could have important implications for how obesity is treated. For example, it could be that people who are beginning to put on a lot of weight have impaired receptors but their neural pathways are still undamaged. If researchers can develop a treatment to block MMP-2, they may be able to prevent obesity.
Of course, the research is in the early stages. But this groundbreaking study could be an important step toward finding an effective treatment for obesity. In the meantime, give these 9 diet tricks a try to cut fat without missing it.