On the fast track
INTERMITTENT FASTING HAS RAPIDLY GAINED FOLLOWERS IN THE MEDICAL PROFESSION AND PUBLIC ARENA, BUT WHY AND HOW DOES IT WORK?
IT’S TEMPTING TO think you can eat your way to good health – swap out those bad foods for heavily promoted “superfoods” and you’ll be well on your way to living forever. The science is increasingly pointing in another direction, to fasting rather than eating different foods, as the path to better health, although most studies on fasting have been conducted on animals, not humans.
Fasting has been shown to improve biomarkers (the biological signs) of disease, reduce oxidative stress (when levels of antioxidants in our body are not high enough to counteract the damage caused by free radicals) and preserve learning and memory functioning, according to Mark Mattson, senior investigator for the National Institute on Aging, part of the US National Institutes of Health.
There are several theories about why fasting provides physiological benefits, says Mattson. “The one that we’ve studied a lot, and designed experiments to test, is the hypothesis that during the fasting period, cells are under a mild stress,” he says. “And they respond to the stress adaptively by enhancing their ability to cope with stress and, maybe, to resist disease.”
In another study, Mattson and colleagues explored the effects of intermittent and continuous energy restriction on weight loss and various biomarkers (for conditions including breast cancer, diabetes and cardiovascular disease) among young overweight women. They found that intermittent restriction was as effective as continuous restriction for improving weight loss, insulin sensitivity and other health biomarkers.
Mattson has also researched the protective benefits of fasting to neurons. If you don’t eat for 10 to 16 hours, your body will go to its fat stores for energy, and fatty acids called ketones will be released into the bloodstream. This has been shown to protect memory in brain and learning functions, says Mattson, as well as slow disease processes in the brain. When you go without food for a short time, your body diverts its energy away from digesting food to cellular repair and the removal of waste material and toxins, a process known as autophagy. Dr Colin Champ, assistant professor at the University of Pittsburgh Medical Centre, explains it like this: “Think of it as our body’s innate recycling programme. Autophagy makes us more efficient machines to get rid of faulty parts, stop cancerous growths and stop metabolic dysfunction like obesity and diabetes.” By boosting your body’s autophagy process through intermittent fasting you dampen inflammation, enhance biological function and slow down the aging process. Intermittent fasting also results in a phenomenon known as apoptosis whereby the body rids itself of old, unhealthy cells, and replaces them with new ones. Researchers have noted that several genes related to longevity and protection against disease are automatically switched on when your body enters a fasting state.