With the rising popularity of the Paleo and Keto dietary trends, you may have also been hearing the term Intermittent Fasting being tossed around like a kale salad. If the idea of fasting brings up images of starvation, deprivation and suffering for days on end, you might want to take another look.
Though it may seem strange that depriving your body of something as essential to life as food could actually be healing, more and more studies are confirming that fasting, particularly Intermittent Fasting, is doing just that and more.
Well-known authors and supporters of the primal lifestyle movement may be at least partially responsible for the resurgence of interest in fasting, but the concept as a health panacea has been around for thousands of years. In ancient Ayurvedic medicine, as well as in the more recent new age yogic traditions, fasting was primarily used as a starting point for healing and cleansing the body. These were typically extended periods of time without any food at all, or with the diet restricted to just one type of caloric intake, such as fruit and vegetable juices.
The term Intermittent Fasting (IF) is used to describe brief, regularly scheduled fasts usually lasting no more than one to three days. Different forms of IF range from restricting the day’s calories to a condensed period of time (eating only between the hours of 8 AM and 3 PM for instance), to sharply cutting calories for two days of the week, or doing one 36-hour fast weekly. The key similarity in each of these forms of fasting is that they are brief, periodic and frequent, as opposed to longer duration fasts once or twice a year.
There is mounting evidence that Intermittent Fasting in particular has health benefits that go far beyond weight loss, extending into disease prevention, reduction and even reversal (diabetes, cancer, heart disease), prolonged lifespan, cognitive function protection, inflammation reduction (arthritis, autoimmune disorders, infection), and enhancement of overall physical performance. Many advocates, including a growing number of celebrities and athletes, also note increased mental clarity and focus as sideline benefits.
For healthy, lasting weight loss, Intermittent Fasting seems to be the golden child. According to studies, the particular style of IF didn’t seem to affect the outcome: significant weight loss in the form of unwanted fat, without the loss of lean tissue (muscle, bone, organ) that normally accompanies calorie-restricted diets.
That’s because, during IF, the body switches one source of fuel (glucose) for another (fatty acids), rather than simply going without. Fatty acids produce molecules called ketones, which are then used by the body as the new source of energy. It is these ketones that spawned the term ‘Keto’. Stephen Anton, a researcher out of the University of Florida calls the process “flipping the metabolic switch”, and goes on to explain:
“This switch can happen after a certain period of time fasting. It’s a gradation in which your metabolism over time shifts to use higher and higher amounts of ketones for energy.”
Another key success factor of IF for weight loss and overall health and disease prevention is that the plans are typically much easier to follow and stick to than other calorie-reduction diets. For example, most research participants found it reasonably comfortable and sustainable to simply narrow their ‘feeding window’ to 6 to 10 hours per day, thereby extending the usual overnight fast by an additional 4 to 8 hours. This is known as ‘circadian rhythm fasting’ as it mimics our naturally adapted metabolic pattern of daytime food, nighttime sleep.
Of course, any dietary plan, including IF, will be vastly more successful when combined with a healthy diet low in refined sugars, grains and processed foods, and high in plant based foods, and high quality fats and proteins. Always check with your doctor or health care practitioner before beginning an IF plan if you have a pre-existing health condition such as diabetes, high blood pressure, or heart disease.