Intermittent Fasting and the Placebo Effect

Wolverine. Anyone who has even a passing familiarity with the X-Men will agree that this Marvel saga would be nothing without Wolverine.

The X-Men comic book series was birthed by Stan Lee and his co-creator, Jack Kirby, in 1963. The 1990s cartoon enthralled my brothers and me with its gritty storylines and complex characters.

The X-Men went on to become a profitable movie franchise starting with its eponymous first release in the year 2000.[1]


By the time of the first movie, the Wolverine character had already existed for almost forty years. However, since that time the star character has become synonymous with Hugh Jackman.

And Hugh Jackman is basically synonymous with being, well, jacked.

Interestingly, Jackman and the character he portrays didn’t always have zero percent body fat. (For the record, whenever the comic version of Wolverine wasn’t in his obscenely yellow full-body costume, he seldom had as much trouble finding a shirt.)

There is a scene in a classic, 1960s-era James Bond movie where the Chief Villain showcases one of his (for-some-unexplained-reason shirtless) thugs to some sort of Junior Associate Villain, who creepily inspects the thug’s abs, replying with something like, “Impressive!” I remember thinking to myself as a kid in the 1990s how this supposedly impressive thug just looked big and fat. Movie standards had changed a ton already. The industry has now evolved to a point where male actors also double as professional bodybuilders (and actresses as yoga models).

I’m not sure where they go next. Negative body fat? Will they become triglyceride black holes, gravitational forces that literally suck the fat from the other actors inhabiting the on-screen universe around them?

Bro Science

Spoiler: It turns out that exposing every abdominal muscle you have is really hard. I’d bet that 99% of adults in America haven’t seen one of their own abs since they were teenagers.[2]

Never fear, though. “Broscience” to the rescue!!

According to numerous broscience sites, so-called “intermittent fasting” is how Hollywood actors achieve their chiseled appearance. This typically involves 15 to 18 hours of fasting between dinner and the first meal of the day.


But what if intermittent fasting has no direct biological benefit? Would that mean that its devotees have been inflicting hangriness on themselves for no good reason?

I’m not sure, but it’s worth considering some reasons why intermittent fasting could have other benefits:

  1. Confidence: Maybe just believing that intermittent fasting will work gives some users enough confidence to make — and sustain! — the other, actual changes required to lose body fat. (Everyone knows the saying that “confidence is key,” but I’d argue that most people drastically underestimate how important confidence is to life success.)
  2. Willpower: Although research on the depletability of willpower seems increasingly in dispute, the literature seems to largely support the idea that willpower is a finite resource to be drained. However, this depletion effect holds on a short-term basis. In the long term, one can grow his or her willpower.[3]
  3. Ritualization: The intermittent fasting schedule may create daily patterns, triggers, and/or an overall ritualistic feeling that make it easier to comply with other healthy habits. This “ritualistic feeling” (cheesy, I know) includes a feeling of building momentum, which can be quite productive.
  4. Hunger: Yes, I’ve listed hunger itself as a benefit. Based on my own trials of daily fasting I’ve begun to understand where the “being hungry” metaphor for hard work and ambition comes from. There’s something about actual hunger that focuses you on the task at hand, even if it isn’t exactly foraging or trapping game.

To summarize, habits can have effects that are are indirect (having the desired effect but in a roundabout way) or ancillary (having other unintended benefits). Some of these effects are based purely on belief like placebo. That being said, most of them are not and include a wider range of causal relationships.

The Takeaway

Whether you try intermittent fasting is not the point, though I’ve had a good experience myself (#consultyourphysician). Most physicians will tell you that the diet that works is the diet you stick to. More importantly and in all aspects of your life, remember that doing something aggressively is nearly always preferable to doing nothing.


Are there some qualities about intermittent fasting that make it particularly beneficial and which we could generalize to help select new habits?

I suspect that this diet has at least two of these qualities: duress (pain) and implementation cost (time, money, energy).

Perhaps the impact of intermittent fasting to one’s life is so large that it crosses certain thresholds that other habits would not (#tippingpoint). For instance, it is hard to forget when you’re doing it, which in a possibly counterintuitive way may foster dedication to what is actually a kind of painful act (at least at the start). There is also some planning involved, which may induce the benefits suggested in the form of schedules and triggers.


[1] The title of one of REM’s albums, Eponymous, always struck me as clever. (Because by naming it that instead of “REM,” the album is no longer actually eponymous.)

[2] If an ab pops out during summer vacation and sees its shadow, it means 6 more years of obesity.

[3] See The Power of Habit by Charles Duhigg plus the Wikipedia entry on “Learned Industriousness.”

→ Check out a discussion related to this one on my podcast, The Warrior Poet: Show #10: Skinny-Fat Life.

About the author: Sri hosts The Warrior Poet podcast, a show on the philosophy of leadership based on his experience in the SEAL Teams, at Harvard Business School, on Wall Street, and in tech. Shows every Monday. Follow him on Instagram @sri_the_warrior_poet.