Debunking the myth that fasting causes muscle loss.
What the evidence says
- Studies of alternate daily fasting over 70 days: fat mass decreased 11.4%, lean mass unchanged1
- Growth hormone increased during fasting to maintain muscle mass1
- Studies of one meal per day found significantly more fat loss than three meals at same calories, with no muscle loss1
- Fat is burned first; muscle breakdown occurs only when body fat becomes extremely low1
- The body preserves muscle mass until fat stores become so low it has no other choice1
- ADF and daily CR both preserve lean mass equally; FFM unchanged in both approaches2
- Review of IF protocols: 3-7% weight loss with lean mass preserved across ADF, WDF, and TRF3
- IF produces marked reductions in visceral fat with retention of lean muscle mass, with improved insulin sensitivity independent of overall calorie reduction4