 [ Symptoms ] i am 16 and 118 pounds i work out 15 20 times per week how many calories should i be eating  i now eat 1 400 [ Disease ] it takes about 15 calories per pound of ideal body weight to maintain your ideal weight i do not know how tall you are or your sex so i can not calculate your ideal weight but you should not have any problems doing that calculation it is not just calories that matter you should be on a balanced diet with sufficient protein carbohydrates and yes even fat if you are only eating 1400 calories a day this amount does not seem to be sufficient i suspect you will lose weight over time eating this much especially if you are working out take a nutrition class