To build muscle, focus on two main factors ... or you can use an online calorie calculator. This one from Mayo Clinic uses the Mifflin-St. Jeor equation, which pros consider the gold standard.

Without protein, you will just gain fat and little muscle", he continues ... work out roughly how many calories you need to eat to maintain your weight using our calculator below and adjust ...

In the world of fitness and nutrition, there's been a lot of talk about whether you can build muscle in a calorie deficit, ...