IF is not necessarily calorie restriction, it's more caloric timing. You can use IF to optimize gaining lean weight (muscle mass) just as you can use it to aid

IF is not necessarily calorie restriction, it's more caloric timing. You can use IF to optimize gaining lean weight (muscle mass) just as you can use it to aid weight-loss. IF is about managing appetite mostly, as the hormone that plays a large role in driving hunger (ghrelin) is highly habitual; the more often you eat, the more often you're going to be hungry. So by reducing the time-window in which you eat, you reduce the window when you'll feel hungry, which can dramatically aid diet adherence. But that's more the everyday form of IF. If you're on a eat-stop-eat type protocol and fast once or twice a week, you're probably using it to ensure you maintain a caloric deficit each week. You're bundling all your reduction in food consumption into one day a week instead of ensuring you're at TDEE-400 calories every day.