Scott Brennan running

Fasting must have been a regular occurrence for our ancient ancestors, yet in America today it is virtually absent. Food is so plentiful that fasting is hardly imaginable.

Yet not long ago, when the winter came and food stocks ran low, our ancestors would make it through on their reserves of body fat. A typical slim and fit man has at least 70 days of reserve calories, most of us probably have months or years.

I started doing some research and was surprised to find there are people who fast regularly for as much as 40 days in a row. That sounds a little extreme, but I think a day or two of fasting on a regular basis would be good for everyone. Let’s review the benefits of fasting:

Fasting promotes longevity

Numerous studies have found that calorie restriction increases lifespan. Whether this is done with a daily low calorie diet, or by intermittent fasting, the results are similar.

One recent study showed that fasting mice survived significantly longer than the full-fed mice, in spite of the fasting group having a heavier body weight than the control group. Mean survival times for fasting and control mice were 64 weeks and 47. That’s a pretty impressive increase. Source.

Another study on the life expectancy of worms found that alternate day fasting had a 40% increase in lifespan, and intermittent fasting (every two days) had a 56% increase in lifespan over the control worms. In contrast, daily calorie restriction only increased lifespan by an average of 13%. Source.

Confirming these studies on humans will take more time than I have to wait. But there is some promising research coming in.

For example, people who fast regularly (once a month) have a 58% lower risk of coronary disease compared with those who don’t fast, according to a report presented at the American College of Cardiology conference in New Orleans. Source.

Fasting helps weight control

Fasting helps maintain weight loss, by reducing your overall energy consumption. Mentally, it proves to yourself that you have the will power to control when, what and how much you eat. This is a tremendous psychological power over your eating that carries on to days you are not fasting.

Contrary to some worries, fasting for a day or two does not lower your metabolism. On the positive side, your body increases production of human growth hormone, which protects your muscle tissues, and helps muscle growth in the days following your fast. Fasting reduces insulin resistance, which aids weight loss.

Fasting induces self-healing

Fasting is often credited with “flushing toxins from your body” and other claims that I could not find studies to support. It does make sense that your body might spend more time healing itself, when it is not spending so much time on digestion.

A well-documented benefit to fasting is autophagy. When you fast, your body goes into a survival mode to secure a ready supply proteins needed for daily cellular functions. Your cells wall off a tiny portion of their cytoplasm and begin to consume everything in it. Damaged portions of the cell are consumed along with healthy portions. When your fast ends, your body rebuilds the consumed portion, making the cell younger and healthier.

Biochemist Ron Mignery wrote a study on how autophagy works called the “Protein Cycling Diet.” He estimates fasting one day a week for 10 years will result in 70% of your cellular material being rejuvenated. Read it here.

Fasting gives sense of wellbeing

The most surprising effect of fasting for me was the improved sense of wellbeing. My spirits were lifted. My sense of control over my body was enhanced. I wasn’t hungry. Overall, I’d say it’s euphoric. That might explain why fasting is an important part of so many religious traditions.

Here’s how I started fasting

A couple of months ago I started a basic 24-hour fast once a week on Tuesdays. I eat dinner Monday night at 5 p.m. and then fast until dinner Tuesday night at 6 p.m. It almost seems too easy, because I’m only skipping two meals.

I decided to try increasing it to 36 hours. It wasn’t as hard as I thought. Then I did it for 48 hours. Afterward it occurred to me that 48 hours was the longest period I had gone without eating in my life – A weird thought.

I have kept it up, alternating between 24- and 36-hour fasts. I am very happy with results and plan to keep up this experiment.

I look at it like exercise. Just like we benefit from a workout where we put our muscles through a temporary period of stress, so we benefit from fasting. It puts our entire body through a short period of stress that we recover from in an improved state.

Try a longer fast?

If you’d like to see more on 40-day fasts, check out how Dr. Alan Goldhamer of True North Health is using water fasting to improve the symptoms of high blood pressure, diabetes, obesity and more. Watch video.