If you ate the number of calories needed to maintain your current weight, you would only lose weight if you exercised. Yes, body weight is composed of tissue that needs calories to perform metabolic work.
You can figure your calorie requirements at your current weight by measuring how many calories you eat a day averaged over a week while maintaining your weight (+ or – 3 pounds is insignificant). Generally, that can be calculated at 12 calories per pound of body weight. So if you weigh 150 pounds times 12 calories, you need 1800 calories per day.
To lose weight, you have to decrease that calorie amount by 500 (lose 1 pound per week) or 1000 (lose 2 pounds per week). If overweight, you eat 2000 calories per day, to lose 1 pound per week, eat 1500 calories per day. To lose 2 pounds per week, eat 1000 calories per day. However, research does not support eating less than 1200 calories per day because quick weight loss is usually regained.
Once you have reached your goal weight, to stop losing weight, you will need to slightly increase your calories. Again, figure 12 calories per pound of body weight to determine weight maintenance. So if your maintenance weight is 130 pounds, you need 1560 calories per day. (Not a whole lot less than you did at 150 pounds.)
At a lower weight, you will probably not need more calories than you did at your overweight unless you have changed the composition of your body. If you have exercised, decreased body fat (gone from 28% down to 21%) and increased muscle, then you may need to increase your calories a bit higher than 1560 per day. Muscles do work and burn calories. Body fat just sits there as a repository for calories in case of a famine.
If you would like your specific calorie needs to be estimated for weight loss and weight maintenance, try my Healthy Body Calculator®. After entering your physical data and whether you would like to lose 1 or 2 pounds per week, this calculator will estimate your Calorie Goal. I would recommend you re-do the Healthy Body Calculator® after every 10-pound weight loss as you will not need as many calories to keep losing and not hit a weight loss plateau. Then when you reach your goal weight, redo the Healthy Body Calculator® and select no weight loss to get an estimate of your Calorie Goal to maintain your weight.
