Weight loss is linked with some loss of lean body mass, regardless of the method used. Intermittent fasting has been shown to match any other calorie deficit in terms of lean body mass loss, rather than more as you're implying.

Regardless of how you lose weight the advice is and remains:

> Eat a minimum of 0.36 grams of protein per day, per pound of LEAN* body weight. Increasing to 0.5-0.7 grams of protein per day, per pound of LEAN* body weight for older adults or when undergoing weight loss.

*LEAN is a vital detail for overweight people, they commonly miscalculate protein requirements due to this. The easiest way for overweight people to determine their requirement, is just find an "ideal body weight calculator" online, enter height and gender, and then multiply THAT figure by 0.5-0.7.

For example a man who is 6' tall and 400 lbs should eat 62 grams of protein per day MINIMUM, but during weight loss 86-120 grams of protein per day. It is common, unfortunately, to read online people in this situation miscalculate this to 280(!) grams of protein per day which is incorrect and harms their weight-loss goals.