Are There Any Health Benefits to Fasting?

Source: Thinkstock

Source: Thinkstock

It is a common belief that fasting will help you lose weight since it entails not eating for an extended period of time. And while this train of thought is seemingly logical, experts have found the opposite effect is true: You put on weight.

According to, fasting results in, more often than not, rebound eating. This means that when the fast comes to an end, you are more likely to consume more calories because you are starving. Or if you are a person who fasts on the regular, then you will consume more calories in anticipation of the fast. The same effect is seen in extreme dieters — when you go for a few days with an extremely restrictive calorie count, then you tend to binge at your breaking point.

While fasting can make you gain weight and sleep poorly, it is not all bad news. A University of Utah study found that occasional fasting was linked with lower rates of heart disease. Specifically, coronary artery disease was found less in subjects who fasted and similar results were seen in subjects who underwent a coronary angiography.

“People who fast seem to receive a heart-protective benefit, and this appeared to also hold true in non-LDS people who fast as part of a health-conscious lifestyle,” said Benjamin D. Horne, Ph.D., M.P.H., study author and director of cardiovascular and genetic epidemiology at Intermountain Medical Center and adjunct assistant professor of biomedical informatics at the University of Utah in Salt Lake City, in an American Heart Association statement. “When we adjusted for smoking, or looked just at the nonsmokers, we still found a lower rate of CAD in people having an LDS religious preference. We thought this was very interesting, so we devised a survey about other behaviors associated with LDS that might bring a health benefit.”

Another study from the University of California, Berkeley, published in the American Journal of Physiology, found a reduce risk of cancer in subjects who fast.

“Cell proliferation is really the key to the modern epidemic of cancer,” said Marc Hellerstein, professor of human nutrition in the Department of Nutritional Sciences and Toxicology at UC Berkeley’s College of Natural Resources, in a university press statement. “Normally, a cell will try to fix any damage that has occurred to its DNA. But, if it divides before it has a chance to fix the damage, then that damage becomes memorialized as a mutation in the offspring cells. Slowing down the rate of cell proliferation essentially buys time for the cells to repair genetic damage.”

And most recently, a study published this summer in the June 5 issue of Cell Stem Cell found that fasting can protect the body from immune system damage and also promote immune system regeneration.

“We could not predict that prolonged fasting would have such a remarkable effect in promoting stem cell-based regeneration of the hematopoietic system,” said corresponding author Valter Longo, Edna M. Jones Professor of Gerontology and the Biological Sciences at the USC Davis School of Gerontology and director of the USC Longevity Institute, in a university release. “When you starve, the system tries to save energy, and one of the things it can do to save energy is to recycle a lot of the immune cells that are not needed, especially those that may be damaged. What we started noticing in both our human work and animal work is that the white blood cell count goes down with prolonged fasting. Then when you re-feed, the blood cells come back. So we started thinking, well, where does it come from?”

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