Calories Needed to Lose Weight
There are estimated 3500 calories in a pound of stored body fat. So, if a 3500-calorie deficit is created through diet, exercise or a combination of both, one pound of body weight may be lost. If 7000 calorie deficit is created, then, two pounds of weight may be lost and so on. The calorie shortage can be achieved either by calorie-restriction alone, or by a combination of fewer calories in (diet) and more calories out (exercise). This combination of diet and exercise is best for lasting weight loss. Indeed, sustained weight loss is difficult or impossible without increased regular exercise.
In order to lose fat, a useful guideline for lowering calorie intake is to reduce calories by at least 500, but not more than 1000 below the maintenance level. For people with only a small amount of weight to lose, 1000 calories will be too much of a deficit. As a guide to minimum calorie intake, the American College of Sports Medicine (ACSM) recommends that calorie levels should never drop below 1200 calories per day for women, or 1800 calories per day for men. Even these calorie levels are quite low.
An alternative way of calculating a safe minimum calorie-intake level is by reference to body weight or current body weight. Reducing calories by 15-20% below daily calorie maintenance needs is a useful start. This maybe increased depending on weight loss goals.