Hey there, I’ll make an educated guess that you have read the post I wrote some time ago in which I said that intermittent fasting is no better than continuous calorie restriction for weight loss

Studies showing that intermittent fasting is no better than continuous calorie restriction for weight loss

And boooy how I pissed off people who like having air for breakfast aka intermittent fasting extremists.

Some ignored the weight of the evidence and kept believing that intermittent fasting is the best thing ever.

Some were more intelligent and said “Yeah, maybe intermittent fasting isn’t better than continuous calorie restriction for weight loss but it offers many other health benefits. Autophagy and stuff, you know.

And so now I am about to piss those people off too (things like that definitely reduce the size of my circle of friends) because a new systematic review and meta-analysis by Chen et al. (2021) found that if you don’t do fasting, you are probably not missing out on much in terms of health: 

Missing puzzle pieces of time-restricted-eating (TRE) as a long-term weight-loss strategy in overweight and obese people? A systematic review and meta-analysis of randomized controlled trials

Ok, let’s pause for a second here because I want you to understand that a systematic review and meta-analysis is not “just another study.” It’s an unbiased way to determine what the science says “on average”: 

A systematic review and meta-analysis is an examination of current data from all relevant studies on the topic to determine overall trends. It’s “a study of the studies,” if you will.

Anyway, the researchers found that there were no significant differences between intermittent fasting and continuous calorie restriction. Most improvements in health markers were similar.

Intermittent fasting caused lower blood pressure and fasting insulin levels (but not blood sugar). However, it increased LDL cholesterol levels (it’s bad). Also, it caused the loss of lean mass (also no bueno and which is why I said you should probably avoid long fasts).

Earlier high-quality evidence such as this meta-analysis

Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials

Also found that intermittent fasting and continuous calorie restriction offer equivalent outcomes in terms of weight loss and health markers—improvements in glucose control/insulin sensitivity, thyroid, cortisol, and sex hormones were similar in both diets.

Although, intermittent fasting suppressed hunger better (it’s not bad, it’s great).

The researchers concluded: 

I don’t doubt that after reading this, heaps of people will wonder why is this? Why intermittent fasting doesn’t seem to improve health markers more than continuous calorie restriction considering all the hype?

No worries. I’ll tell you why:

It’s due to weight loss. Naude et al. (2014) estimated in their meta-analysis that most, if not all, health benefits happen simply due to the lost weight itself rather than the diet type

At this point, some intermittent fasting zealots will become so angry that their teeth will start to fall out. Right before the last tooth comes out, they will mumble something like “Hey, you caveman, ever heard about autophagy? Intermittent fasting causes your body to “self-eat” damaged organelles in the cells which increases longevity.

That is 100% correct (assuming a calorie deficit) but what they don’t know is that autophagy isn’t fasting-specific. It happens in any diet that puts you in a calorie deficit. Autophagy is the result of calorie restriction, not fasting (Anton and Leeuwenburgh, 2014): 

Aging is characterized by an exponential increase of oxidatively damaged proteins, and caloric restriction has been found to downregulate the expression of genes involved in oxidative stress and ameliorate oxidative damage in several different tissues.

Listen, I’m not trying to shit on intermittent fasting. I’m trying to shit on people who tried fasting, liked it, and now they assume everyone else should do it based on pseudoscience.

As Jeremy Clarkson once said: 

There’s nothing wrong with having a belief. But there is something dreadfully wrong when you believe that everyone else in the world must share it. “I don’t eat meat and you can’t either.”

Multiple studies have demonstrated that intermittent fasting can be an effective tool to create a calorie deficit and, therefore, lose weight. It can be as effective as continuous calorie restriction.

If you find intermittent fasting sustainable, can be consistent with it, it doesn’t take over your social life, it improves your relationship with food, and allows you to make progress, there is nothing wrong with it.

But it’s not magic

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Originally published by me on Medium on November 9, 2021

This Post Has 4 Comments

  1. Rita

    I’ve done IF for over 2 years for at least 6 days per wk. I usually eat between 11am and 5pm, so 18/6. For me, it wasn’t about losing weight as much as it was about not being a slave to eating 3 meals a day which I have always struggled with. I never wanted breakfast as a child and my mom would make me eat “something” so most of the time it was a slice of toast with peanut butter. I spent years forcing myself as an adult to eat breakfast because we kept hearing that it’s the most important meal of the day.and I bought into that bs. I feel better NOT eating breakfast so I rarely do eat breakfast unless I have guests from out of town and then I eat about half the amount or less that everyone else does. It’s just not my thing. Love doing IF.

  2. Egis R.

    Which is why IF works so great for you – it fits your preferences, schedule, and lifestyle. Most people will start IF purely because they hear something about “magical 16 hours.”

  3. Karen Rimmer

    I tried intermittent fasting for about 6 months. Overall, I did not enjoy it. I lost a few pounds in the beginning, which was encouraging, but my big take-aways were 1) I need breakfast and 2) I need breakfast. The only thing I found beneficial is I was more disciplined about not eating after a certain time of day. Your recent post about meal planning is where it’s at for me – that has proven to be the most useful tool to keep me on track, even with my self imposed deadline of not eating past 8:00 p.m. (at least most days, but I do allow myself days here and there if my calorie intake isn’t way over.)

    I really appreciate your review/analysis/overview of all these studies!! I struggle to find time in the day to accomplish what I’m required to do, much less conduct a lot of research and figure out what it all means to me. So…thank you!! I love your posts!

  4. Egis R.

    No worries. Thank you for reading.

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