Third, the amount of calories actually consumed during periods of eating is an extremely important factor. It is close to impossible to make any type of significant muscle increase if calories are being restricted to excess.
The idea of intermittent fasting is usually to get the metabolism fired up during times of fasting, not to limit the amount of calories taken in over the course of the day. This is especially important for those who workout regularly. If energy levels become too low, the body will start breaking down bone and limiting testosterone production to conserve energy for necessary physiological functions. (3)
With this said, it is important that short cuts are not taken to reach caloric goals. Eating full, balanced meals every 1.5-2 hours with perhaps one larger meal mixed in will allow for optimal health and muscle growth during a period of fasting. Eating junk that’s high in calories won’t cut it and performance will almost definitely suffer.
The moral of the story is that like any more intense training methods, whether utilizing diet or workout modifications, results will happen with the proper discipline and an educated approach. Know the why behind every program you do.
References
1) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2375570/
2) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5371748/
3) https://www.nih.gov/news-events/nih-research-matters/understanding-how-testosterone-affects-men