In years past, the practice of fasting was usually associated with religious or spiritual customs and traditions. But now, a growing number of fitness enthusiasts are beginning to include intermittent fasts in their lives, depending on goals and circumstances, as a way to lose fat and improve overall health and longevity.
Intermittent fasting (IF) makes perfect sense from an evolutionary point of view. Our paleolithic ancestors went through regular cycles where food was either readily abundant or extremely scarce. So we evolved with episodes of caloric deprivation.
During times of scarcity, the body turns on “repair and maintenance” genes. These genes increase the production of key chemicals, such as glutathione, which promote the repair of tissues that would not otherwise be repaired during times of surplus. It is this adaptation that allows cells to live longer.
Intermittent fasting involves a period of fasting alternated with a period of eating and may be done in a number of ways. An alternate-day fast generally involves a feast day where you eat all you want one day and then fast the next. A single twenty-four hour fast can be done once a week, once a month or whenever you decide, on a less planned schedule. You can also skip a meal on a planned or unplanned basis.
The condensed eating window is the method I prefer. It involves compressing your daily intake into a set number of hours. For example, I’ll eat from seven in the morning until about three in the afternoon. Then fast until seven the next morning. This gives my body a sixteen hour break from digesting. And it happens quite naturally, on occasion, with no great effort.
A recent article in the American Journal of Clinical Nutrition summarized the IF research on animals and humans. In the animal studies, researchers found that IF increases fat loss, reduces blood pressure, improves insulin sensitivity and glucose tolerance and improves cognitive function. They also found a reduction in the incidence of cancer, diabetes and heart disease.
There have been far fewer studies done on humans and the findings are much less conclusive. More research is needed to determine whether the benefits found in animals also apply to humans and if they will translate into long-term health gains.
More on this to come….