Hey, did you see that study about the researcher who did the thing and then this other thing happened to the subjects? No? Well, I find it fascinating which is why I’m about to walk you through that study.

Why am I doing it? Because despite a dearth of evidence, many people still believe intermittent fasting is a unicorn diet better than any other diet for weight loss. Spoiler alert: it’s not.

A recent 12-week randomized clinical trial put 116 overweight or obese subjects into two groups:

The consistent meal timing group was instructed to eat 3 structured meals per day. Snacking between meals was permitted. The time-restricted eating group was instructed to eat ad libitum from 12:00 pm until 8:00 pm and completely abstain from caloric intake from 8:00 pm until 12:00 pm the following day (16 hours fast:8 hours eat)

The interesting thing about this study was that the researchers were like listen, eat within this time of window, we don’t give a flying crap how many calories and protein you will consume nor do we care about your physical activity.

The researchers gave no calorie or nutritional recommendations because the goal was to see if following the 16:8 intermittent fasting protocol results in greater weight loss independent of other nutritional interventions in a real-world situation where all that people do is jump from one flashy diet to another without ever taking time to educate themselves about calories and macronutrients. 

The investigators chose a 12 pm to 8 pm eating window because they reckoned people would find skipping breakfast rather than dinner easier because most social occasions happen in the evening and blah blah blah let’s fast forward to the results.

Based on the title of the article, you’ve probably got wind of the study outcome — there was no significant difference in weight change between 16:8-hour time-restricted eating and consistent meal timing:

16:8-hour time-restricted eating (−0.94 kg/2 lb) and consistent meal timing (−0.68 kg/1.5 lb)

This tells us that in the absence of other nutritional interventions [hint: calorie deficit] intermittent fasting doesn’t cause any magical weight loss benefits. A sustainable calorie deficit still has to be achieved within the eating window for weight loss to occur.

Oh, and btw, approximately 65% of weight lost in the intermittent fasting groups was due to the loss of lean body mass. Only ~35% — fat mass. Which is why you need to read my article (with grand rapidity) on how to maintain muscle mass when dieting.

Now, perhaps you’re thinking: But what about health? I heard intermittent fasting offers an assload of health benefits.

Haha, nope. Just like many previous studies, this one also found no significant differences in fasting insulin, glucose, HbA1C, or blood lipids between the groups. And if you’re a returning reader here, you’ll be like yeah, Egis, that sounds about right because you’ve told me before that most health benefits happen simply due to the lost weight itself rather than the diet type. 

But some of the new readers (especially if they are intermittent fasting lovers) might play the autophagy card. For those people, I politely reply: Er… stop it! Autophagy is the result of calorie restriction, not fasting. I wrote about this before so read it, maybe?

Practical applications

  • Intermittent fasting is an attractive weight-loss strategy that doesn’t require tedious calorie-counting but fasting itself doesn’t cause weight loss. Calorie deficit, patience, and consistency always come first.
  • If you like having hard rules on when to and when not to eat, intermittent fasting might work wonders for you as it may improve dietary adherence.
  • Intermittent fasting isn’t magical or something you have to do to lose weight or improve your health. It’s just a tool in your toolbox to reduce calorie intake (and hunger for some people) and if it’s something you enjoy and can stick to long-term, then by all means follow it.

Now excuse me, I need to get ready for the possible attack by the intermittent fasting zealots army in the comments section. Wish me luck. Bye.

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Originally published by me on Medium on February 8, 2022

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