Work out your ‘goal TDEE’ to tone up or gain muscle. The amount of calories you’ll need per day to tone up depends on your goal — whether you’d like to lose fat as well as gaining muscle, or just gain muscle without losing any fat.
To lose fat while gaining muscle mass, subtract approximately 500kcal from your TDEE — your body will use up the remaining calories from your energy stores. This energy can be taken from both fat and muscle tissue. To minimize muscle tissue loss and to keep your BMR high, it’s important to keep on top of weight training and eat enough protein (we’ll get to this later).
If you’d only like to gain muscle, studies suggest you should add around 500kcal to your TDEE. Take body measurements every few weeks. You can either increase your intake in increments of around 250kcal if you’re not gaining muscle, or if you find you’re gaining too much weight in the wrong places, decrease your intake slightly.
Recalculate your calorie requirements every few weeks to make sure you’re eating the right amount for your changing weight.
Lose fat and gain muscle mass: YOUR TDEE – 500kcal
Gain Muscle mass only: YOUR TDEE + 500kcal