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by numinoid 1614 days ago
Research is showing that most (all) of the benefits related to IF are due to fat loss. As long as calories in - calories out are equated, there is no statistically significant difference between a regular caloric deficit and IF. This isn't to say IF is bad, adherence is the most important part of any diet. If it works for you great, but there's not any evidence that it's superior to any other form of diet in terms of bio markers.

There's really not enough evidence for longer multi day (5+) fasts at this point either, but it's a promising avenue of research.

EDIT: https://pubmed.ncbi.nlm.nih.gov/32363896/ https://pubmed.ncbi.nlm.nih.gov/34733895/

5 comments

I can't read the full text of one of the articles, just the abstract. Both studies focus on weight loss of obese and overweight people. 35% were diabetics, and 70% had high cholesterol.

You attribute the benefits to a specific mechanism, fat loss, but what the summaries say is that IF is effective for weight loss and is similar to tradition calorie reduction diets without suggesting the causal chain. You've attributed a mechanism whereas the abstracts didn't.

"In conclusion, IER improves anthropometric outcomes and intermediate disease markers when compared to a usual diet. The effects of IER on weight loss are similar to weight loss achieved by CER."

and

"Conclusions: Intermittent energy restriction is an effective alternative diet strategy for weight loss and blood pressure control and is comparable to CER in overweight and obese patients with hypertension. "

I'm at my target weight (5'11@160 lbs / 1.8m@72.5kg), so the data from obese/overweight people doesn't apply to me. I'm interested in possible health benefits of increased insulin sensitivity and autophagy, which it seems like these didn't really investigate.

I think you're missing the point. A diet's success depends on how hungry it makes you feel. A diet with a 100 calories per day deficit where you're never hungry is (obviously) superior to a diet with a 100 calories per day deficit where you're always hungry. The advantage of IF is to reduce hunger.
This ignores the (admittedly under-researched) aspect of autophagy after 12-14 hours of fasting.

It's also not clear from your sources whether there actually was a caloric equivalence in the diets. Dietary patterns can significantly affect base metabolic rate, which is the biggest problem with just caloric restriction, where your base metabolic rate is lowered. This means you eventually stop losing weight while also being restricted to consume fewer calories. It's a vicious cycle.

Anecdotally, you can lose weight with just restricting your feeding window to 8 hours while eating "normally". Perhaps that inadvertently results in caloric restriction, but it feels different. As such, it's more sustainable.

Can you link some of that research for the benefit of other readers?
Your gut biome uses a none zero amount of calories to stay alive so there is some nuance for calories in - calories out.