The National Heart Lung and Blood Institute (NHLBI) reviewed the medical research on diets and issued the following guidelines about limiting caloric intake and successful weight loss:

• Reducing caloric intake by 500 - 1,000 calories (also called kilocalories or kcals) per day from the current level will produce recommended weight loss of 1 - 2 pounds per week.
• In general, doctors should recommend diets of 1,000 - 1,200 kcal/day for most women and 1,200 - 1,600 kcal/day for men.
• Eating a low calorie diet leads to an average weight loss of 8% over 3 - 12 months.
• Eating less fat without reducing calories is not sufficient for weight loss.
• Reduced-calorie diets are more likely to be successful if the patient is educated about food composition, labeling, preparation, and portion size.
• The patient’s preferences should be taken into account when formulating a diet plan.
• Patients should have open communication with their doctor or nutritionist during the period when they are first adjusting to the diet.

After reaching a healthy target weight, you may make minor adjustments to your daily caloric intake to maintain your weight. You can use the following formulas to estimate the total number of calories to take in each day while maintaining your present weight. These are not a substitute for consulting with your doctor or nutritionist, but they provide a rough estimate:

• Consume 10 calories per pound of desirable body weight if you are sedentary (very low activity level).
• Consume 13 calories per pound of desirable body weight if your activity level is low, or if you are over age 55.
• Consume 15 calories per pound of desirable body weight if you regularly do moderate activity.
• Consume 18 calories per pound of desirable body weight if you regularly do strenuous activity.