How many calories does it take to lose one pound?
— Countin' Cal
Dear Countin' Cal ,
Theoretically, about 3500 calories equals one pound of body weight. This means that you'd have to take in 3500 fewer calories than you usually do, over a period of time, to lose one pound. Keep in mind, this is in theory; what happens in the real world can be very different.
Often, as you eat less, your body expends calories at a slower rate (that is, your metabolism decreases). Perhaps this occurs to ensure survival, or just to defend a comfortable body weight. In any event, this slowdown is a real phenomenon, and has been shown in many laboratory studies — it's called diet induced adaptive thermogenesis. If your calorie expenditure falls, it can be increasingly difficult to take in few enough calories to lose weight. This can be quite a frustration and challenge to the person trying to shed some pounds.
So, while it's nice to have an equation that works in the lab, the 3500-calorie figure may not play out so tidily in reality. However, it can serve as a goal if you are trying to lose weight. By cutting 500 calories a day (a total of 3500 per week), and otherwise eating a balanced diet, you may find you lose approximately a pound a week. This rate of weight loss is considered reasonable and healthy.
While simple math might suggest that someone could cut thousands of calories per day and shed pounds in the blink of any eye, more realistic and lasting weight change happens gradually. Skipping meals can actually have a negative impact on weight management. To keep your metabolism speeding along, consider having four or five smaller meals and snacks throughout the day. In addition to providing consistent energy and maintaining your metabolism, you may be more likely to resist those "snack attacks" that happen with extreme hunger. Finally, an important factor in keeping your metabolism moving is participating in regular exercise, which is good for you regardless of whether you're trying to lose weight or just curious about calories. Check out the related Q&As for some ideas on getting fit and feeling great!Alice!