Doctors To Advocate Fasting?

One of my closest friends is a distinguished MD and researcher who hit me up this week to share a very recent review article from the New England Journal of Medicine.

The topic: intermittent fasting.

At this point, everyone has either tried it or made fun of people who won’t shut up about it. You know what those people sound like.

“Breakfast is the most important meal of the day” is the slogan of the American capitalist propaganda machine used to cell more Fruit Loops.

You’ve never felt real biological hunger.

It’s a great way to lose pounds before a show.

Wait that last one was Hansel from Zoolander talking about eating disorders. Kindly ignore him.

By any rate, fasting has surged in popularity in recent years. I have been doing an 18/6 schedule 5x a week for almost 3 years. It’s certainly crossed-over from fad to lifestyle change. My favorite benefit is actually mental. It’s de-cluttering. It means fewer decisions. It means never feeling like you’re supposed to eat something because N hours have passed. But most people who fast are interested in its promise for their health or weight loss.

So what about this review article?

Wikipedia says a review article is where “journals analyze or discuss research previously published by others, rather than reporting new experimental results.” The NEJM review of the studies on intermittent fasting was very positive. A few bullets that stood out to me that confirmed my own reading about IF.

  • Many studies have indicated that several of the benefits of intermittent fasting are dissociated from its effects on weight loss. These benefits include improvements in glucose regulation, blood pressure, and heart rate; the efficacy of endurance training and abdominal fat loss.
  • In humans, intermittent-fasting interventions ameliorate obesity, insulin resistance, dyslipidemia, hypertension, and inflammation. Intermittent fasting seems to confer health benefits to a greater extent than can be attributed just to a reduction in caloric intake.   
  • Repeated exposure to fasting periods results in lasting adaptive responses that confer resistance to subsequent challenges. Cells respond to intermittent fasting by engaging in a coordinated adaptive stress response that leads to increased expression of antioxidant defenses, DNA repair, protein quality control, mitochondrial biogenesis and autophagy, and down-regulation of inflammation. These adaptive responses to fasting and feeding are conserved across taxa.
  • Intermittent-fasting regimens reduce tissue damage and improve functional outcomes of traumatic and ischemic tissue injury in animal models. Preoperative fasting reduces tissue damage and inflammation and improves the outcomes of surgical procedures… Emerging evidence suggests that intermittent fasting may enhance athletic performance and may prove to be a practical approach for reducing the morbidity and mortality associated with traumatic brain and spinal cord injuries in athletes.

Why is this important?

The NEJM is not Men’s Health or Cosmo. It’s the gold standard of medical journals.

My friend writes:

Being published in NEJM is often considered the equivalent of becoming “textbook” in medicine and it’s rare that NEJM would comment on this type of subject.

My Commentary

I’m not qualified to evaluate any medical study. We need to rely on experts for that. This is an uncomfortable truth in a complex world. A world in which people devote their life’s work to incremental findings. For a layperson to understand these tiny advances would be, to borrow a Seinfeld metaphor, like trying to hear the sound of cotton touching felt.

To navigate such a world, we put our energy into curating who we listen to. We have heuristics for doing this as we try to separate reliable sources from charlatans. One of the most useful heuristics is considering incentives. We don’t take Big Tobacco’s scientists at face value.

Supporting intermittent fasting passes the incentives heuristic easily. The work on it is relatively recent and nobody has a commercial incentive to push it (ie food companies) so in a Bayesian sense, it takes less to convince me. Said otherwise, I don’t have to discount some profiteer’s incentives in the findings.

Feels like a rare spot where truth and interests align.
Here’s the link to the NEJM but there’s a paywall. Might need to google around to see if you can backdoor it.

My prior research on fasting

The majority came from a book called Eat.Stop.Eat by Brad Pilon. It also does an extensive literature review and digs into what we know and don’t know about fasting durations, performance in athletes, and lots of interesting studies about Muslim athlete during Ramadan which provides natural experiments in calorie restriction. (Link)

I was also highly impacted by Dr. Peter Attia. You can start with my notes from his interviews.

  • Invest Like the Best Podcast notes (Link)
  • Notes from his livestream with Patrick O’Shaughnessey (Link)

A Simple Diagram to Remember

Attia has a  simple framework for how to manage your diet.

You have 3 levers to pull:

Calorie restriction
Time restriction
Diet restriction

Always pull 1. Often pull 2. Occasionally pull 3.

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