[ilija139]

It says caloric restriction without malnutrition. Eating 15% less carb and fat calories won't make you loose any more muscle mass than you would have otherwise.

But I am wondering my self too, what's the effect when you combine CR with exercise. 15% out of 2000 calories is 300 cal or about 30 mins jogging. So instead of eating less, will the effect be similar if I spend 300 cal more everyday through exercise?

[stevenwoo]

There was a thread last week https://news.ycombinator.com/item?id=30381000 that discussed scientist(s) doing studies that debunk the theory that burning more calories during exercise leads to weight loss - your body compensates by burning fewer calories at rest so the daily calorie budget your body needs stays more or less constant for vast majority (possibly all) of people and exercise/diet combinations.

[nradov]

Malnutrition is a vague term that can mean many different things. You can lose significant muscle mass even if you aren't technically malnourished.

You absolutely can lose muscle mass if you cut carb and fat calories below a certain threshold. Whether that threshold is above or below 15% depends on many factors. The Real Science of Sport podcast has a good explanation of how this works.

https://play.acast.com/s/f3fb5c75-b943-4f5d-bd87-27c91611dd2...