What if we call it calorie cycling instead?

In previous posts,  I’ve looked at the merits of something they’re calling Alternate Day Modified Fasting (ADMF) as a way to lose weight.  But the word “fasting” appears to have a lot of baggage–to many, it implies extreme, dangerous, or even disordered eating.

ADMF is not really fasting at all.  A more accurate term, Calorie Cycling, is now gaining traction and this rebranding may allow people to get  beyond their assumptions and preconceived notions for long enough to evaluate this approach on its merits.

There seems to be a deeply entrenched–but completely arbitrary–notion that we should eat the same number of calories every day. Fans of the evolutionary nutrition movement would point out that primitive man certainly did not have the luxury of constant, consistent access to food. We now suffer from an epidemic of over-nourishment. Maybe it’s time to think outside the box a little?

The Logic Behind Calorie Cycling

If you were to cut your normal daily caloric intake by a third, you would lose weight–and fairly quickly. But there are problems with this approach to weight loss:

1. You will probably experience hunger.

2. Staying on the regimen requires constant vigilance, monitoring, and self-control.

3. After about 72 hours of sustained caloric restriction, your body will adjust by slowing its metabolism (slightly).

So, let’s say we take the same reduced number of calories. But instead of spreading them evenly throughout the week, we alternate very low calorie days and normal or slightly above normal days.

Instead of this:


you have this:


Over the course of the week, you’d consume the same number of calories on either regimen and experience comparable weight loss.  And, for the sake of argument, let’s assume that in both scenarios, you are eating a well-balanced array of nutritious foods.

Does calorie cycling offer any advantages?

Well, for one thing, because there is no sustained calorie restriction, your body does not adjust its metabolism or start catabolizing lean muscle tissue as it would on a sustained low-calorie diet.  Additionally, some people report that calorie cycling requires less will-power than constant restriction. Although you may feel hunger on your low-intake day, you can eat to satisfaction on your high-intake day. Contrary to assumptions, research shows that most people will eat only slightly more calories than normal following a skipped meal or fast.

As a bonus, some studies suggest that calorie-cycling may have benefits unrelated to weight loss, such as reducing oxidative damage, improving insulin resistance, and slowing mitochondrial aging.

Calorie cycling clearly isn’t for everyone, and I’d strongly encourage anyone considering it to check in with their doctor or nutrition professional first. Those suffering from hypoglycemia, pregnant, or with a history or risk of eating disorders are not good candidates, for example. Aside from health issues, some people may simply prefer or be more successful on a more traditional approach.

But for some, it may be a helpful alternative strategy. At the very least, I think it’s worthy of further investigation and study.


5 thoughts on “What if we call it calorie cycling instead?

  1. I am curious about why outright long-term fasting is never recommended for weight loss. Obviously it is not a sustainable lifetime strategy but, apart from that, it seems ideal for obese people looking for emergency intervention. By all accounts, fastest do not even experience hunger after a day or two.

  2. I’m not sure exactly what you would consider “outright long-term fasting” but long term extreme calorie restriction is regularly employed in a variety of guises, and although it produces the expected result (rapid weight loss) it also often results in semi-permanent metabolic adaptation that makes maintaining the weight loss extremely difficult.

    1. I was referring to the scenario examined in half a dozen trials done in the 60’s where subjects were allowed nothing but water and, sometimes unadulterated coffee or tea. They were kept on this zero calorie regimen for periods ranging from 14 to 100+ days straight. Lead authors include Gilliland, Blondheim, Bloom, Drenick and Harrison. I don’t have access to all of the full studies but there seemed to be a common theme which was 1) it was remarkably effective at producing short-term weight loss; and 2) participants pretty universally reported an absence of hunger after a day or two and many reported “euphoria”; and 3) the negative collateral health consequences were either non-existent or minor and resolved themselves upon re-feeding.

      It seemed like there was a minor groundswell of support for this idea during that decade which vanished almost as quickly as it appeared. I’m curious about why as I don’t think the concept of metabolic adaptation was on anyone’s radar screen at the time. If anything, I think there were studies back then that refuted that idea.

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