In Eat Stop Eat, Pilon proposes that fasting once or twice per week for 24 hours is a very effective approach for both weight loss and overall health. According to Pilon, these intermittent fasts combined with an otherwise overall healthy diet will result in slow, steady weight loss, increased growth hormone levels, increased lipolysis and fat burning, decreased insulin levels and increased insulin sensitivity. He dismisses several of the myths surrounding fasting. He presents research that debunks the view that fasting decreases metabolism, and shows how brain functioning can actually be enhanced by restricting calories by fasting periodically. He discusses studies that shows that short periods of fasting will not cause muscle loss or significant deterioration in athletic performance.
Pilon's overall formula is simple...eat lots of fresh fruits of vegetables, other healthy foods, but do not stress over what you eat, fast once or twice per week, and do at least 2 sessions of resistance training per week. He claims that if you do a reasonable job of eating healthy and do not overeat on the days you do not fast, you should reap health and weight loss benefits. Pilon's advice regarding resistance training makes sense. The research shows that fasting and reasonable calorie restriction does not result in muscle loss if combined with resistance training. Pilon is more relaxed than I am about the correct food to eat. My intention is to continue to eat a whole foods plant-based diet as I incorporate periodic fasting.
I have only recently started to do weekly 24 hour fasts, so I am not yet able to provide support for this concept. On the few days that I have fasted, however, my energy and concentration levels are at least as good, if not better, than on other days. I start to feel a little uncomfortable after about 20 hours of fasting, but if I stay mentally or physically active during this period, and distract myself with activities, the 24 hour period goes by without any major negative issues. In fact, it is nice to have these periods without having to fuss about what to eat, and to devote time to food preparation. I may even be saving some money. I suspect that the more I fast, the easier it will be.
Since I have been consuming a very healthy whole foods plant-based diet for the past few years, I believe that I have 'trained' myself well for fasting. Therefore, my transition may be a bit smoother than those eating the standard American diet. Even those of us who attempt to eat a very healthy diet undoubtedly overeat because we are conditioned from childhood to eat frequently (at least three meals per day). I have found that as I have moved towards a whole foods plant-based diet made up mostly of low calorie, high nutrient foods with lots of fiber, I can go much longer between meals without feeling uncomfortable.
For example, on most days I stop eating after my evening meal, and don't feel hungry again until late the next morning. Admittedly, I have had to recently make a concerted effort to avoid late night snacking. For some reason, my hunger tends to be heightened at night. This is probably because I am home surrounded by lots of food and had gotten into the habit of eating at 9 or 10 at night. With a little conscious effort, and the realization that I am not truly hungry at this time because I just finished eating dinner a couple of hours ago, I have been able to wean myself away from night time eating. So most nights I finish dinner about 7 - 8 pm and, do not eat again until 10 am or so the next morning. I invariably start to feel somewhat hungry in the late morning after a 14 hour or so 'fast'. These routine 14 hour 'fasts' have made it easier for me to adjust to the longer 24 hour fasts.
In the process of experimenting with fasting, I have concluded that hunger is a very interesting phenomenon. On page 41 of Eat Stop Eat, Pilon states, "The true feeling of real hunger is difficult to explain and I’m not sure many of us have ever really experienced it. We have felt the withdrawal of not being able to eat when we wanted to, and the disappointment of not being able to eat what we wanted to, but true hunger is reserved for those who have gone weeks without eating and are not sure when or where their next meal will come from."
Joel Fuhrman, M.D. speaks of toxic hunger in his book Eat to Live, and provides a concise definition on his DiseaseProof blog. I have concluded that one of the components of a healthy lifestyle is to avoid eating in response to 'toxic hunger' or other psychological clues that cause us to snack. We will benefit by recognizing the difference between true and toxic hunger, and eating only when physiologically in need of food. In addition to the other health benefits of short fasts, experiencing longer periods between meals can help teach us to recognize the difference between true and culturally-conditioned hunger.
Fasting periodically also can be a way to decrease the overall number of calories consumed. Research has shown that calorie restriction can enhance longevity. Much has been written about this subject. One especially interesting article Biological Effects of Calorie Restriction: From Soup to Nuts by Stephen R. Spindler, Department of Biochemistry, University of California, Riverside, Riverside, CA provides an excellent overview of the topic.
So, in summary, I have decided to give once or twice per week 24 hour fasting a try for several reasons:
- Fasting should assist me to maintain my weight, and perhaps result in some additional fat loss.
- The research shows that short term intermittent fasting can result in overall calorie restriction, which has been shown to improve health and longevity.
- Fasting will help me to further bring my hunger urges under control and recognize the differences between culturally-conditioned 'toxic' hunger and true hunger. Hopefully, this will help me to continue to improve my ability to avoid overeating.
- There should be no 'side effects' from fasting. Research shows that my metabolism should not be adversely affected, that my blood sugar levels should stay normal, that I will not experience muscle loss or decreases in athletic performance. In fact, if I lose more body fat, my athletic performance should improve.
- On days that I fast, I should actually feel good and may have even more energy.
It will be interesting to see whether I can sustain these periodic fasts over a long period, and also avoid some of the potential pitfalls. For example, I need to resist the temptation to overeat, once the fast ends. Pilon advises that once the fast is over, pretend it never happened, and return to eating sensibly.
A very good book on the therapeutic benefits of fasting is Fasting and Eating for Health by Joel Fuhrman, M.D.