BCAAs can play an important role in a low-calorie diet. Losing weight requires a negative calorie intake. But as soon as you achieve a calorie deficit, you run the risk of your body breaking down muscle tissue instead of fat. When you take BCAAs, they immediately provide your body with the amino acids leucine, isoleucine, and valine, meaning your liver doesn’t have to metabolize them first. These amino acids supply energy directly and prevent the body from tapping into muscle proteins. So when you’re trying to lose fat, BCAAs help you maintain a maximum amount of muscle tissue.