Since I last posted about the benefits of fasting for health, more supporting evidence has been found. As these four studies show, there seems to be something important happening when we go for a period of time without calories.
Fasting may lower the risk of heart disease. 200 patients undergoing a cardiac cath to get an angiographic image of the arteries of their heart were asked whether or not they fast occasionally. Those who said they did had a 58% lower risk of having blocked arteries than those who did not. Although this study, presented as an abstract at the recent American College of Cardiology meeting, doesnt prove cause and effect, its an interesting association that may be explained by changes in metabolism that occur with occasional fasting things like levels of growth hormone, an agent that gets released when theres little food intake. Growth hormone triggers the body to burn fat and protect muscle mass. Read about the study here.
Fasting protects the brain and spinal cord. In a model of spinal cord trauma that involves loss of function of the legs, eating every other day, whether initiated before or after injury, promotes re-growth of nerves and the recovery of movement. Simply restricting the usual calories eaten every day to 75% of usual does not have the same effect. That means its not about the number of calories, its about giving your body a break from the constant ingestion of food. (Jeong MA et al. Intermittent fasting improves functional recovery after rat thoracic contusion spinal cord injury. J. Neurotrauma Mar;28(3):479-92, 2011.)
Fasting can slow aging and ward off dementia. In mice that are genetically programmed to have a shorter lifespan, fasting every other day corrected specific protein deficits in the brain. The replenished proteins are important contributors to brain cell survival and growth. (Tajes M et al. Neuroprotective role of intermittent fasting in senescence-accelerated mice P8 (SAMP8). Exp Gerontol. Sep;45(9):702-10, 2010.)
Fasting doesn’t interfere with athletic performance. Lots of people around the world fast for religious or cultural reasons. During Ramadan, for example, people fast when the sun shines (often up to 18 hours) every day for one month. Studies of fasting athletes show little evidence of decreased performance. Any effects are quite small and may be related more to sleep deprivation since all eating must occur during night-time hours. (Maughan RJ, Fallah J, and Coyle EF. The effects of fasting on metabolism and performance. Br J Sports Med. Jun;44(7):490-4, 2010.)
Fasting helps with weight loss. The latest review of existing evidence for the effects of intermittent fasting (IF) indicate it is just as effective as reducing the overall amount of calories eaten on a daily basis when it comes to losing weight. The great part about IF though is that on non-fasting days dieters eat whatever they want without restricting quantity and they dont lose lean muscle mass. That makes limiting calories a lot more enjoyable and healthy. (Varady KA. Intermittent versus daily calorie restriction: which diet regimen is more effective for weight loss? Obes Rev. 2011 Mar 17. doi: 10.1111/j.1467-789X.2011.00873.x.)
I’m a fan of intermittent fasting (IF). Every other evening eat an early dinner, between 5:00 and 6:00 in the evening, then skip breakfast in the morning, and eat lunch around noon. That makes for an 18-hour fast, essentially the window of time needed for our metabolic machinery to reset to maximum efficiency without detrimental effects. An IF schedule such as this fits with the advice of ancient Yoga gurus as written in the Gheranda Samhita.