Why You Should Fast…Occasionally

Those of you that have completed Live It, NOT Diet!, know I’m an advocate of fasting. As it essentially gives you the opportunity to benefit from an overall reduction in calories, without the damaging effects (and difficulty) that come with calorie restriction diets.

By avoiding food for an entire day, we can expect many of the health improvements that come with an overall reduction in calories.  Which starts with an increased resistance to neurotoxins and oxidative stress (via higher levels of vitamin E and coenzyme Q10) that would otherwise promote disease and accelerate aging.

During fasting, the body upregulates it’s protection against oxidative damage (to proteins and DNA), and this is likely why it’s proven effective in fighting various cancers, neurodegenerative disorders, and heart disease.


And don’t feel bad if you’re skeptical. When I first heard about fasting, I was too. Not only because I’m against eating less as an approach to losing weight and improving our long-term health, but because (like most fitness enthusiasts) at the turn of the century I still believed in “eating every 2 hours” and “eating 6 meals a day” to avoid “losing muscle.”

But, this is why I paid close attention to the evidence when I learned that during fasting the body burns strictly body fat and SPARES MUSCLE!  For instance:

A 2011 study compared a calorie restriction strategy to intermittent fasting, and found equal fat loss but only intermittent fasting retained muscle.

Which is arguably because of the increase in growth hormone (which supports muscle building and fat burning) and increase in catecholamines (which elevate metabolism and body fat release):

Growth hormone increases have been recorded at 1300% for women and 2000% in men during the course of a 24hr fast!

And makes perfect sense when looking back at our primal ancestors.  Who were performing various strenuous activities during extended bouts without food – using their catecholamines (adrenaline and noradrenaline) and fat storage to carry out these tasks.


Fasting essentially accelerates fat loss, by elevating the hormones that burn fat, and inhibiting those that store it (insulin).  Or as the Lead Researcher in a 2011 study from the Intermountain Medical Center puts it:

“Fasting causes hunger or stress. In response, the body releases more cholesterol, allowing it to utilize fat as a source of fuel, instead of glucose…This is important because the fewer fat cells a body has, the less likely it will experience insulin resistance, or diabetes.”

But all that being said, there’s a right and a wrong way to fast. As this study from 2005 in the American Journal of Clinical Nutrition demonstrates, we see unfavorable consequences in health and body composition when fasting is excessive.

Participants following an alternate day fasting protocol for 3 weeks lost 2-3% of their body weight, but only 57% of it was fat.


One could hypothesize that restricting calories to this extent (3 days of no food/week), creates an unfavorable hormonal environment similar to what you’d expect with consistent calorie restriction.  Where muscle loss is high, energy burning (resting metabolic rate) is low, and our body adjusts negatively to the scarcity.

This study from 2013 found a reduction in testosterone and disruption in the reproductive system following a 12-week alternate-day fasting protocol.

Or simply put – fasting is great, and it’s clearly a practice you should take part in; but it’s a dish best served “occasionally.”

Stay Lean!
Coach Mike


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