Could it be time to go on a hunger strike—against heart disease and diabetes? Researchers at the Intermountain Medical Center in Utah reported in two new studies that fasting—not eating or drinking anything but water—for 24 hours once a week may be linked to a lower risk of these diseases.
In the first study, researchers asked 200 people if they fasted regularly. The findings: Those who said they fasted were 12 percent less likely to have both diabetes and heart disease than those who didn’t ever go without grub.
In the second study, a separate group of 30 people—none of whom had fasted before—were asked to put down their forks for 24 hours. Researchers then compared the subjects’ post-fasting blood samples to those taken after a day of normal eating. The results? The scientists observed that the male participants’ levels of human growth hormone (HGH) were 20 times higher on the days the men fasted than when they followed a regular day of eating.

What’s so great about HGH?
When your body senses you’ve run out of food, it triggers your pituitary gland to release the HGH. This hormonal surge causes your body to use more fat for energy, instead of breaking down muscle, explains lead author Benjamin D. Horne, Ph.D., M.P.H.
Horne thinks that this explains why those who fasted regularly were less likely to have heart disease or diabetes. His contention: HGH reduced their body fat, which in effect lowers the risk of these diseases, he explains. When researchers pooled this study data with the results of a previous study on a different group, the fasters had slightly lower BMIs than non-fasters. (The researchers didn’t specifically record body fat measurements in this study.)
A drawback: Twenty-four hours—the length of the current study—is nowhere near enough time to judge fasting’s long-term benefits, and the surges of HGH might only last a day or two, says Horne.

Fasting for Health: What the Believers Say
Health experts don’t usually recommend fasting because it’s believed that your body will break down your muscle tissue for energy. But contrary to popular belief, there’s no evidence that fasting for as long as 72 hours reduces your muscle mass, says Brad Pilon, author of Eat Stop Eat, a weight-loss plan combining fasting with weight training.
These studies looked at long-term and short-term fasters. But how does it work for regular guys who want to be lean? While Pilon acknowledges that there’s a lack of experimental studies to support fasting, he claims that his clients have effectively used the strategy to lose fat, improve their cholesterol, and lower their blood pressure levels.
The bonus, Pilon says, is that fasters walk away with an entirely different relationship with food. “You no longer have to continuously plan your day around the timing of your next meal, and you may be resetting your body’s expectation of when and how much you are going to eat,” Pilon points out. Further, he says, when you do start eating again, you’ll replenish what your body needs, instead of fueling a continuous cycle of digesting, absorbing, and storing extra nutrients. “Think of it like filling a hole as opposed to creating a mountain,” says Pilon.
Pilon recommends one to two 24-hour fasts per week, during which you can drink water, black coffee or tea, diet soda, and herbal tea—but nothing with calories.
Research is Limited
But still, there’s no definitive proof fasting has any special perks, explains“Researchers have yet to do a prospective randomized controlled trial, where they assign some people to fast and others to eat the same amount of food in a more typical pattern, then follow them both see what happens,” he says.
Though Aragon doesn’t recommend fasting until there are more studies, Horne says that the occasional bout of 24-hour food abstinence is safe for most healthy adults. After all, if you consider the eating habits of earlier humans, it wasn’t uncommon to feast without knowing how long it would be until the next meal.