Unlock the Secret to Longevity: Can Intermittent Fasting Add Years to Your Life?

"After two days of “fasting” on less than 500 calories, my mind seems much clearer and sharper. Instead of being tired, as most people I’ve shared this with expected, I feel energized."

It was about three years ago, as I recall, that a fellow called into my radio/TV program to suggest that a great way to slow aging and normalize weight was an intermittent fasting program called the 5:2 diet.

It involved eating normally five days a week and then eating no more than 500 calories for two days in a row, then back to normal eating for the next five days and so on. Several books have been written about it and it’s been the subject of quite a bit of good science, the most recent reported last week in The Washington Post.

Fasting, it turns out, triggers a series of metabolic changes in the body that extend life and reduce the risks of everything from cancer and diabetes to vulnerability to infection. It does so, in part, by causing the body to inhibit a naturally-occurring enzyme in the human body known as mTOR, or the “mechanistic Target Of Rapamycin.” 

This enzyme, mTOR, is, as the authors of a 2013 Nature article noted in the title of their piece, “A Key Modulator of Ageing and Age-Related Disease.”  The authors noted in their abstract that finding drugs to “slow ageing” was inevitable, and:

“A leading target for such interventions is the nutrient response pathway defined by the mechanistic target of rapamycin (mTOR).”

They noted that when the mTOR enzyme was blocked in various animals, including primates like us, it both “extends lifespan” and “confers protection against a growing list of age-related pathologies.” 

A new study just published in the JAMA (Journal of the American Medical Association) Network Open found that 16 weeks of rigorously following the 5:2 diet produced a better result for Type 2 diabetics than even taking the widely-prescribed anti-diabetes drug Metformin.

Our bodies are generally running in one of two modes: Build or repair. In build mode, the mTOR pathway (and others) direct us to manufacture fat from extra calories and use nutrients and calories to sustain our normal metabolism.

In the repair mode, which we enter when we fast for more than a day, our body begins to burn that fat to drive metabolism while also scavenging the body for old cells that are still alive but have ceased, because of age, to do their jobs. They’re essentially zombie cells, using up energy and space but doing nothing more than draining resources from the body.

Through a process called autophagy, such zombie (senescent) cells are broken down and their raw materials recycled for use by new and functional cells. It’s like a major housecleaning of the body, resulting in greater metabolic efficiency and less of a burden on the body’s systems.

Apparently eating more than 500 calories a day is the threshold that tips the body out of autophagy/repair and into the normal “build” metabolic mode. In all probability this reflects an evolutionary process with deep roots in the early human experience, when periods of feast and famine were common.

It also probably explains why people who survived the Nazi death camps — and had experienced prolonged starvation during that experience — tend to live around 7.1 years longer than people who never underwent that horrible experience.

Takarudana Mapendembe wrote about this at greater length in his Healthy Body Is Yours Substack newsletter last week, noting extensive scientific reports detailing how it helps with insulin sensitivity, weight loss, greater mental clarity and function, reductions in inflammation, improved immune system function, hormone regulation, better digestion, and reduced heart disease.

When Louise and I were first married, we read Arnold Ehret’s 1910 masterpiece Rational Fasting. We’d already become vegetarians because of both our spiritual practice and our opposition to the Vietnam War, but this added a whole new dimension to our eating lives; we regularly did 2- and 3-day water- and juice-fasts and continued the practice well into the years when we were raising our three kids (who all grew up vegetarian).

After that caller told me about the 5:2 diet and how it had transformed his life (and body), we started doing that as well and have noticed some real benefits.

One of my favorite things about it is that after two days of only 500 calorie meals I’m really hungry, something that most Americans literally never experience. I can’t describe what an utter pleasure it is to dig into a good meal when in a true state of hunger, as opposed to the “appetite” we normally experience.

I also find that after two days of “fasting” on less than 500 calories, my mind seems much clearer and sharper. Instead of being tired, as most people I’ve shared this with expected, I feel energized.

Check out the book The Fast Diet by the British scientist who figured out that 500-calorie threshold and how it could be used to produce the same or nearly the same effect on the body and mind as a couple of days of water fasting. It’s brilliant, and even if you don’t struggle with weight or diabetes, this is an important addition to the literature on health.