Eat Stop Eat: Intermittent Fasting for Health and Weight Loss

by Brad Pilon

Recent research suggests the problem is that we spend as much as 20 hours a day in the fed state.6 We are constantly eating and storing food and we never really give ourselves a chance to burn it off.

The bottom line is that food has very little to do with your metabolism. In fact, your metabolism is much more closely tied to your bodyweight than anything else. And, your metabolism is almost exclusively tied to your lean body mass or “LBM”. This means all the parts of your body that are not body fat.

The only other thing that can affect your metabolism (in both the short term and long term) is exercise or movement. Even in the complete absence of food for three days, your metabolism remains unchanged.

prolonged caloric restriction is the only proven nutritional method of weight loss.

The sugar in your muscles is used up quickly during high intensity exercises like weight training and sprinting, but even a few consecutive days of fasting in the absence of exercise has little effect on muscle glycogen content.19 By doing so, your muscle glycogen is truly reserved for the energy needs of exercise.

In plain English, they found that a three-day fast had no negative effects on how strongly your muscles can contract, your ability to do short-term high intensity exercises, or your ability to exercise at moderate intensity for a long duration.

I see no reason why you cannot exercise while you are fasting.

Here is another interesting benefit of exercise while fasting. There are metabolic pathways that actually help maintain your blood glucose and glycogen levels while you are fasting, and exercise has a positive effect on these pathways.

or a strenuous activity is more of a psychological need than it is a physical need.

Fasting has little to no effect on most forms of exercise, and exercising while fasting may actually make your fast feel easier by helping to maintain blood glucose levels and glycogen stores.

There is one imperative rule that goes along with this statement. You have to be involved in some sort of resistance exercise, such as lifting weights. Now, to be clear, you do not have to weight training at the exact same time you are fasting, but resistance training must be occurring at some point for your muscle mass to be preserved in the face of a caloric deficit.

Even more good news comes from the fact that your weight workouts don’t have to be painfully long to be effective.

Finally, research has clearly shown that fasting for as long as 72 hours (regardless of whether or not you are exercising) does not cause an increased breakdown in your muscle, nor does it slow down muscle protein synthesis.40,116

Fasting and low-calorie diets DO NOT cause you to lose muscle mass if you are resistance training.

While the common belief is that you need to “eat big to get big”, recent research has shown that any extra calories consumed above your estimated daily needs do not contribute to muscle gain. In fact, almost every single extra calorie can be accounted for in fat mass gains42.

While protein intake is also a hotly debated topic, I have found through my review of the existing research that intakes above the current recommended daily intakes does seem to aid in muscle growth and that any protein containing meals consumed within 24–48 hours following a resistance exercise session will contribute to muscle growth.

While long-term caloric restriction on its own can cause you to lose muscle mass, the combination of caloric restriction with resistance exercises has been proven to be very effective at preserving your muscle mass.

Often times, periods of fasting have been associated with being more alert, ambitious, competitive, and creative. Not only that, but you are no longer having to continuously plan your day around the timing of your next meal, and you may be “resetting” your body’s expectation of when and how much you are going to eat.

According to the research I reviewed on the effects of short-term fasting on blood sugar, a 24-hour fast should not place you into a hypoglycemic state,63 and I have not seen any research that has shown a subject going below 3.6 mmol/L blood sugar during a short-term fast.

The researchers concluded that there is no doubt that some people may find eating less to be more stressful than others, but as long as no other metabolic disease is present, the ability to maintain blood glucose in the normal range does not seem to be effected during a 24-hour fast. They then speculated that the symptoms of hypoglycemia could in fact be related to anxiety and stress over not eating, as opposed to being caused by low blood sugar.

In fact, other studies have found that it takes about 9 straight days of fasting before a significant decrease in testosterone levels are observed.91

Research examining the effects of brief fasting (14-18 hours) over 21 days found that testosterone levels were not affected by almost a month of short-term fasting.

These findings all point to the fact that short-term fasting does not have any negative effects on testosterone levels, and certainly would not cause serum testosterone levels to ever drop below normal. In fact, based on this evidence this may be one area where brief periods of fasting are actually better than prolonged dieting — since the short periods of fasting do little to disrupt testosterone levels, whereas longer more sustained periods of caloric restriction do seem to negatively affect testosterone levels in men.

For close to three decades now, nutritionists and nutritional texts have been recommending breakfast as an important part of healthy eating habits, often quoting the “most important meal of the day” marketing mantra.105

By about the 12 to 14-hour mark, you begin to burn predominantly body fat as your main fuel source.

Epinephrine and norepinephrine are fight-or-flight hormones, often called adrenalin and noradrenalin, or collectively, “catecholamines”. They are released from the adrenal glands during periods of stress; including times when food is absent (such as fasting) and during intense exercise. When they are released into the blood stream, the catecholamines trigger the release of glucose from energy stores, and increase fat burning. They also make you feel awake and alert.

Research has shown that short-term fasting can result in a six-fold increase in growth hormone levels.

Fasting will help us lose body fat, and growth hormone plays a major role in this process (you really can’t burn body fat without GH), but we cannot expect fasting to have steroid- like effects or be some miracle hormone that will cause us to lose fat AND build massive muscles.

it’s not just the loss of body fat that is having an effect, eating less, and exercising also have direct effects on reducing inflammation175, so by doing all three you create a synergistic “attack” on inflammation.

the benefits of fasting don’t only come just from the time you are fasting, but also the time after the fast. Just like with exercise, there needs to be recovery time for you to get the full effects. That’s why I recommend at least 48-hours of time in between each 24- hour fast.

The bottom line is that the Eat Stop Eat lifestyle should free you from obsessive compulsive eating, but this should not be at the expense of simply learning to obsess about your fasting.

The bottom line is that almost everyone can fast for 24-hours, but NOT everyone can do more. For that reason, 24-hours once or twice per week, separated by 2 to 6-days of normal, responsible eating and regular exercise is the Eat Stop Eat prescription for weight loss and overall health.

If I could describe Eat Stop Eat without using the word “fasting” it would be, “the freedom to choose when you eat, and also when you don’t eat”.

Eat less, while enjoying the foods you eat. Eat lots of fruits and vegetables, and lots of herbs and spices. And maybe most importantly, spend less time stressing over the types of food you are eating.

An optimal workout schedule should allow each major muscle group to be exercised roughly twice per week, which scientific research suggests is a sufficient amount for causing muscle growth and the preservation of muscle while you are dieting.

Examples of this style of workout would include any combination of sets and repetitions that allow a muscle to fatigue between the 6th and 15th-repetition.

Besides simply building muscle, the effect of exercise on mood, self-esteem, and body image cannot be stressed enough. After all, what good is losing weight if you still don’t feel good about yourself?

In some very interesting research published in 2008, it was found that when a group of women who exercised regularly were forced to stop exercising for 72-hours, there was a noticeable decrease in their body satisfaction and mood. The results of this study also showed that after 72- hours of non-exercise, feelings of tension, anxiety, and sluggishness were increased.

You should look forward to your next workout session, not dread it. And never let it define who you are as a person.

The simple approach is the one that works best, and this approach involves eating for fat loss and working out to preserve (or even increase) the size of your muscles. Try to be as active as possible, while also allowing yourself ample recovery time. Add cardio only if needed, only if you find it enjoyable, and have the available time.

Some weeks you may fast twice, others only once. Some weeks you may lift weights 4-times, others you may only lift only twice. The key to keeping this lifestyle sustainable is to always remember to keep it flexible and adapt to stresses and needs of your everyday life.

Eat less, stress less; move more, lift more, and get a good night’s sleep. For physical health, that’s pretty much as good as it gets.