Sunday, April 18, 2010

Intermittent Fasting Part Two- Hormones, tissue repair and your brain

In Intermittent Fasting part one we covered The basics of how to get stared with IF, Fight or Flight/Rest and Digest states and fat loss.

Today I'd like to cover your body's hormonal responses to IF along with tissue regeneration and repair.

There are a few beneficial hormones which are proven to increase production during fasting. This is where it gets a little bit tricky for me because I want to educate you about hormonal response without making this into a  chemistry lesson so bare with me while I attempt to break it down into laymen terms (considering I myself am a layman).

Ther first homone I'm going to talk about is called  Beta-hydroxy butyrate, or BHB.  BHB is a hormone which is created during fat metabolism. In part one I told you that during a fast your body switches from burning glucose for fuel (gluconeogenesis), to burning fat instead. I also told you that fat metabolism is much more at producing energy than glucose. Also, according to Scott Kustes From, BHB is also also has a hand in preventing Parkinson’s and Alzheimer’s, hypoxia (low oxygen levels), insulin resistance, and free radical damage. there appears to be a direct link to brain repair and fasting as well. When someone experiences a head trauma such as  a concussion, one of the body's first responses is to loose it's appetite I seriously doubt this is coincidence.

Two other hormones known to increase during a fast are Human Growth Hormone (hgh) and Insulinlike Growth Factor (IGF-1) These are two powerful hormones that are key players in muscle growth, fat burning, tissue repair and strength. It tuns out  that exercise recovery is increased during a fast and exercise while fasting can produce a hormonal double  whammy. The two things known to increase production of these hormones are fasting and intense exercise. So it turns out that your body is primed to exercise during a fast and recovery is accelerated when pairing the two together. I know that when I am lucky enough to be able to exercise regularly while fasting I have more energy during the fast, can work out harder and experience less muscle soreness afterward.

HGH and IGF-1 are also known to drastically decrease from aging.  This interferes with the body's ability to regenerate itself as we get older. Since IF is known to increase these hormones  then it is reasonable to believe that IF can have positive effects on overall longevity and the body's ability to regenerate itself as we get older.

Studies done on two groups of rats, one group fed on a regular schedule, the other group fed with an alternate day caloric restriction diet, have shown that the calorie restricted diet lived longer and remained healthy much longer than the other group. And this was done on an alternate day Caloric restriction where one day they ate approximately half as much and on the other day, they ate as much as the other group. IF has been shown to have the same  or more benefits than caloric restriction but without the potential negative effects because there is no calorie restriction. You still eat overall the same amount of calories, just in a condensed window.

In conclusion, I strongly feel that IF can have positive effects on energy production, exercise recovery, tissue repair, longevity,  maintaining cognitive function, overall health and wellness and maintaining a good body composition. Please give it a try, it is a lifestyle that once you start, for most, you won't want o go back to your old eating ways again.


  1. Great connections with BHB, I've been fasting so much these days and my muscle recovery is insane... I however am still confused as to why, but I will look up a few more things from this post, thanks

  2. Fasting ramps up the hormones testosterone and Hgh. These hormones are primarily responsible for muscle building and recovery. That's why many of us find energy and recovery so much better when we train fasted.

  3. a couple years ago I destroyed my wrist in kickboxing. I had pain for over a year after. It hurt to turn a page in a book. I started fasting and within a few months I never felt it again. Seems like a no brainer! My father is 65yrs old, has a bad back and eats morning to night. I tried to convince him but his wife is a nurse and says its dangerous. So frustrating. Yet they won't read the articles I provide them.

  4. I don't understand. Isn't the health benefit of fasting a reduction of IGF-1?