The New England Journal of Medicine recently featured a review article titled “Effects of Intermittent Fasting on Health, Aging and Disease” written in cooperation by the NIH and Johns Hopkins University. They start out the review by pointing out that it is a blatant misnomer that humans should eat three meals a day plus or minus snacks (excepting the rare individual with special nutritional needs). They go on to point out that over the million and a half years that humans have evolved our metabolic machinery has been programmed to eat less often and to sustain frequent short fasts. Then comes the modern era of grocery stores, refrigerators, and fast food restaurants and with it a decline in health fueled primarily by obesity, but also by the uncoupling of healthy metabolic and immunologic pathways.
The main benefits of fasting are: the reduction of free-radical production, improved glucose regulation, improved stress resistance and suppression of inflammation.
The two main ways to fast are either intermittent (once a week) fasting for an entire day or by doing “time restricted” eating. The former can be achieved by reducing your calorie intake to 500 calories for one day a week. The latter can be achieved by eating your usual daily caloric intake during 6 hours and fasting for 18 hours.
One of the main benefits of fasting involves the metabolic shift from glucose to ketones as an energy source. Ketones act not only as an energy source but as potent signaling molecules that slow aging and reduce inflammation.
The authors go on to cite hundreds of research articles demonstrating the benefit of fasting to help diabetes, cancer (both the development of cancer and its spread), neurodegenerative diseases, asthma, MS, and arthritis.