It is common knowledge among body building circles that calorie restriction causes muscle loss. In other words, if you eat below your maintenance calories you lose muscle mass.
Calorie Restriction And Muscle Loss – True or not?
I personally am guilty of subscribing to the “calorie restriction makes you waste muscle” notion. I used to eat 6 times a day. I used to eat a high-protein meal pre-workout and a high-protein/carg meal post-workout. I was especially careful not to train on an empty stomach or not to miss “feeding my muscles” right after my workout, so as to avoid immediate muscle loss.
Well, it turns out that training in a fasted state (like in Intermittent Fasting) or in a state of calorie restriction does not cause muscle loss. The main condition in order to preserve your muscles is to exercise them. Stated differently, if you use them you won’t lose them (1, 2)!
Still, can you lose muscles while restricting calories (dieting or Intermittent Fasting)?
Yes, you can.
How?
If you diet and don’t exercise at all (not even walking) eventually you will lose muscle, along with fat. Again, it goes back to not using the muscles.. Which is generally true for everything – if you don’t use it Nature takes it away.
I am a living proof of the fact that resistance training preserves (and can even help you gain) muscle while being calorie deficient. I have been doing Intermittent Fasting for about 4 months now and I’ve lost fat and gained a bit more muscle. I train, using my own body as weight, only 3 times a week.
Here are two photos of me, taken today after 16 hours of fasting (it’s almost 1 pm and I haven’t eaten anything since last night 9 pm).
Bottom line is this: Decreasing calories and/or skipping meals (like pre- and/or post-workout) WILL NOT cause you to waste muscle mass AS LONG AS you exercise those muscles.
I do it, drug-free bodybuilders have been doing it for many, many years: doing their resistance training, while being calorie-restricted for many weeks and coming out very lean and big on contest day.