I eat mine back because I follow mfp. It works out your calories based on just doing day to day living so if they give you 1400cals to eat and then you burn 200cals that means you can have those extra 200 to get back to your goal of 1400cals, if that makes sense. I eat them back because otherwise I get too hungry and Im aiming to give my body enough food to manage the workouts and day to day things. I feel too sluggish and tired if I dont eat all my calories or get within 100cals to goal