If your diet is making you hungry, the odds may be against you for meeting your weight loss goals. Experiments with mice suggest that when you severely cut back on calories, appetite sensing neurons in your brain begin a cannibalization process, releasing compounds that trigger an irresistible urge to eat. Scientists theorize that disabling that process with drugs could help people resist hunger and combat obesity in a society of cheap, plentiful calories.
Starve your body, starve your brain
Specialized brain cells in your hypothalamus, the gland in your brain that keeps your system balanced, transmit hunger signals when they are starved for calories. These signals also slow down your metabolism–a combination of hunger and sluggishness that destroys willpower. Researchers at the Albert Einstein College of Medicine in New York believe they may have pinpointed this biochemical mechanism that foils so many diets.
Flipping the appetite switch in mice
Appetite sensing neurons signal feelings of hunger via a process called “autophagy,” which literally means “self-eating.” Autophagy breaks down a cell’s used parts to harvest energy. Most cells in the body respond to starvation diets with autophagy. Until now, brain cells were believed to be exempt from autophagy. But the Albert Einstein College of Medicine study discovered that appetite-sensing neurons are unique to other brain cells.
Autophagy in appetite sensing neurons increases cellular compounds called free fatty acids. Higher levels of free fatty acids signal these specialized brain cells to release an appetite-inducing protein called agouti-related peptide (AgRP). In the study, researchers disabled the autophagy process in the appetite sensing neurons of mice. Because the production of AgRP was blocked, the hunger signals during times of starvation stopped. These mice were leaner, more active and ate less than normal after being starved.
A biochemical cure for obesity?
Scientists often use mice as biological models for humans in their studies. It is likely that blocking autophagy in human appetite sensing neurons could get the same results. Because AgRP is unique to appetite sensing neurons, the researchers suggest that blocking this process should only affect appetite signaling, not the cellular breakdown critical to harvesting energy in other parts of the body.
In a report on the study published in the journal “Cell Metabolism,” the researchers said of their finding, “It has tremendous relevance to fighting obesity.” The report also suggests that people on high-fat diets, with chronically high levels of free fatty acids in their blood, could be riding AgRP on a vicious cycle of overeating and low metabolism that results in life-threatening obesity.
Healthy eating, not hunger
Meantime, the researchers are continuing to study these mice to learn how disrupting this neural pathway can help change the eating habits in humans. However, knowledge about how your brain responds to your diet may go a long way to helping you meet your weight loss goals.
Let the scientists play with their mice. Weight loss is about healthy eating, not hunger. Eat less more often. Shop for low-calorie density foods. Get more exercise. Stay focused on results.