To lose weight, you have to cut calories, but if you cut too many from your diet, you may not lose any weight, and you probably won’t be able to stick to your diet for very long because you’ll lack essential nutrition and that will make you feel hungry all the time.

Don’t cut your calorie level drastically when trying to lose weight; this strategy will backfire. Your body is programmed to defend your usual weight, so when calories are cut severely — to fewer than 800 to 1,000 a day — your metabolic rate adjusts to conserve the few calories you do give your body. You won’t lose weight any faster than if you allowed yourself to enjoy 1,200 to 1,500 a day.

Fortunately, when you overeat occasionally, your metabolism speeds up to burn the extra calories, too — ever striving to maintain your normal weight.

Because there are 3,500 calories in a pound and 7 days in a week, you can cut your daily calorie intake by 500 to lose 1 pound a week (3,500 ÷ 7 = 500). To lose 1 1 /2 pounds, you need to cut 750 calories a day. A 2-pound-a-week loss means eliminating 1,000 calories a day. A faster rate of weight loss is generally associated with weight regain and yo-yo dieting. Remember the tortoise and the hare: Slow and steady wins the race.

Suppose you know that your present calorie level is about 2,472 calories each day. To lose 1 pound per week, you need to cut 500 calories a day, bringing your weight-loss calorie level to 1,972. To lose 1 1/2 pounds a week, you new calorie level would be 1, 722 (2,472 – 750 = 1,722). Attempting to lose 2 pounds per week means that your calorie allotment would drop to 1,472 calories. This amount, while still safe, may be too low for your personal needs.

Too much food isn’t the only cause of obesity; lack of exercise is also part of the formula. So when you think about dieting, you need to redefine your definition to mean cutting calories and upping exercise.

If you’re not eating many calories now and a reduction of 500 to 750 calories per day would put your calorie intake below 800 to 1,000 a day and, therefore, put your metabolism into low gear, use the 20 percent rule. It’s a healthier way to lose weight.

First, figure out the average number of calories you eat now.

After you determine the average number of calories you consume, simply subtract 20 percent. Suppose you eat about 1,800 calories a day and would like to lose 20 pounds. Your calculations are as follows:

1,800 calories x 0.20 = 360 calories
1,800 calories – 360 calories = 1,440 calories

If you cut your calorie consumption by about 360 calories to 1,440 calories, you can lose between 1/2 and 3/4 pound a week — a healthy rate of loss that won’t leave you starving. In about seven months, you should reach your goal.