text: how many calories does a person have to have every day?   generally, nutritional labels go off of the 2,000 or 2,500 calorie diet.  so, if you need more or less calories, you need to adjust.  it really depends on the person's metabolism and activity level.    even body type cannot determine how many calories a person needs each day. for example, a big guy may have a slow metabolism, and conversely, a small guy could have a high metabolism.  a person with higher metabolism needs more calories a day and vice-versa.  also, the more active you are, the more calories you need.  because, you will be burning up calories through your cardio exercises.  in addition, you probably have more lean muscle mass which burns calories as well.  i personally aim for 2500-2700.  i have a fairly high metabolism and i am pretty active.