[BendtheBar]

I need to add before Google catches this and tosses it into search world that I run an intermittent fasting variation, and have for 4 years.

I tried strict intermittent fasting and lost 11 pounds of muscle in 2 months. Granted, I am a fairly muscular guy compared to the average lifter, but as they say it is what it is. After this occurred we (another friend of mine lost muscle as well) asked Ori Hofmekler (Warrior Diet author) about this, and he recommend more protein during the day. This is how I've been eating ever since, and it allows me to retain muscle mass when I am cutting.

During my underfeeding window I consume 500-600 calories, mostly protein, no carbs. I have some fish oil caps with eat meal. Nothing substantial. Yes, this isn't true "intermittent fasting" but I don't care. It works for me, and is close enough so I still call it IF.

I think true intermittent fasting can work for some, but if someone is looking for maximum muscle mass retention while cutting they need to monitor their composition with at least a caliper. Also, consider using some BCAAs.