Stay Hungry Longer with Intermittent Fasting

The first time I spoke with Frank Zane I asked him what his nutritional approach was when prepping for a show. How was he able to get so lean? His answer, “stay hungry longer,” couldn’t have been more fitting. This statement perfectly depicts the inner workings of fat loss and lends itself beautifully to intermittent fasting.

What is intermittent fasting? In its true form, intermittent fasting is blending alternating periods of fasting (no food intake) with refeeding (food intake). It is often described alongside calorie restriction, a dietary intervention where calories are reduced significantly (15-60%), while still maintaining sufficient micronutrient intake.

Recent research has demonstrated that the beneficial effects of caloric restriction, including improved glucose metabolism, successful brain aging, reduced inflammation and improvements in cardiovascular health, can be mimicked by intermittent fasting [1][2]. The potential benefits all stem from the unique physiological changes that occur when the body undergoes limited energy intake.

From the hypothalamus in the brain to the gastrointestinal tract, the human body is constantly communicating with itself about energy status. As you get further from your last meal, energy stores become depleted and a host of hormones are released. This is when hunger sets in. The body gets your attention by releasing a major hunger hormone, ghrelin. But with ghrelin comes growth hormone, so if you can manage this initial nudge to eat, you can reap some benefits.

Growth Hormone will increase lipolysis (breakdown of fat for energy) and help spare muscle tissue by limiting amino acids being oxidized. There are a few other mechanisms that occur during short fasts that protect muscle as well. One study found that even fasting up to 40 hours still did not stimulate catabolic processes and lead to muscle loss [3].

As you continue with no food, your insulin levels will stay low. Insulin is a storage hormone that is often referred to as our “fuel selector switch.” One of the major health and physique enhancing benefits of intermittent fasting stems from its ability to increase insulin sensitivity and improve blood glucose levels [2]. When insulin is low, the body shifts to using more stored fat for fuel. As opposed to higher levels of insulin shifting the body towards carbohydrate metabolism. So during your fast, fat becomes the main energy source.

Why is this superior to traditional dieting? When looking at recent studies, intermittent fasting has proven to be more effective in maintaining lean mass and decreasing body fat when compared to daily calorie restriction {4,5}. When attempting to get lean, maintaining lean muscle should always be a priority. This lends itself nicely to weightlifters as you can enjoy a surplus of calories around training sessions and counter with fasts during periods where you aren’t training for a nice synergistic effect.

Fasting and Metabolism

It was once assumed that not eating lead to an immediate decrease in metabolism. In fact, people would refer to this as starvation mode. This is ridiculous. Starvation mode is a very serious condition where bodily processes begin to shut down. This takes days to occur. More recent studies have shown that short fasting periods (up to 60 hours) actually increase metabolism [6,7].

This happens because the body taps into the sympathetic nervous system and releases the catecholamines (epinephrine and nor-epinephrine) to provide energy. Thousands of years ago there were not McDonald’s on every corner. We may have gone days no food. Without being able to drum up enough energy to go hunt and find our food with little energy intake, we would not be here today. The human body is a lot more resourceful than most give it credit for.

How To Implement Intermittent Fasting

There are many forms of intermittent fasting, from alternate day fasting to daily fasting. The length and frequency of the fasting period should be based on your current goals. For a reduction in fat, you want to mobilize and utilize fatty acids during your fast. You do this by performing some activity in the fasted state.

Waking up and performing cardio on an empty stomach is an easy way to do this. If you continue your fast after cardio, you will continue to utilize stored fat as fuel. A common method is to fast until 1pm since skipping breakfast is relatively easy to fit into people’s schedule. It’s important to remember that these calories aren’t lost, they are meant to be made up during your “feeding” phase. It’s also essential that you stay hydrated during this time.

If you are interested in the potential anti-aging or longevity effects of fasting, the fast period should be longer in length (24-36+ hours). The longer the fast, the more stress is placed on the cells. While this sounds troublesome, it’s this stressor that boosts the resiliency of the body’s cells to oxidative stress. This engages a cellular degradation process (autophagy) that gets rid of dysfunctional cells.

Final Thoughts

I challenge you to think outside the norm and find what works best for you. The research on intermittent fasting is out there and the benefits are plentiful. Instead of maintaining the same caloric deficit each day, you can cycle your calories to ensure workouts stay productive and maximize fat loss outside of the training window. I have used this set-up with bodybuilders and power lifters with great success.

[1] “Caloric restriction and intermittent fasting: Two potential diets for successful brain aging.” Bronwen Martin – Mark P. Mattson – Stuard Maudsley – Ageing Research Reviews – 2006

[2] “Effect of Intermittent Fasting and Refeeding on Insulin Action in Healthy Men.”National Center for Biotechnology Information. U.S. National Library of Medicine, Dec. 2009. Web.
[3] “Actions of short-term fasting on human skeletal muscle myogenic and autogenic gene expression.” Larsen AE, Tunstall RJ, Carey KA, Nicholas G, Kambadur R, Crowe TC, et al. Annals of nutrition and metabolism. 2006;50950: 476-481.
[4] “Intermittent versus daily calorie restriction: which diet regimen is more effective for weight loss?” K.A Varady – Obesity Reviews – 2011

[5] “Ramadan Fastings Effect on Plasma Leptin, Adiponectin Concentrations, and Body Composition in Trained Young Men.” National Center for Biotechnology Information. U.S. National Library of Medicine, 18 Dec. 2008. Web.

[6] “The American Journal of Clinical Nutrition.” Leucine, Glucose, and Energy Metabolism after 3 Days of Fasting in Healthy Human Subjects. N.p., n.d. Web. 04 Aug. 2014.

[7] “Resting Energy Expenditure in Short-term Starvation Is Increased as a Result of an Increase in Serum Norepinephrine.” National Center for Biotechnology Information. U.S. National Library of Medicine, 7 July 2000. Web.