Your body mass index, or BMI, can help you determine your calorie needs for the day. Of course, your individual needs are based on your weight management goals. Although BMI is a good general estimator of body fat, it isn’t accurate in every case. A women with lots of muscle, for example, might weigh above the “ideal” range but still have very little body fat.
If your BMI is less than 18.5 you’re considered underweight; BMIs of 18.5 to 24.9 are within a normal range, while 25 to 29.9 is classified as overweight. BMIs of 30 or above are categorized as obese. To calculate your BMI, multiply your weight in pounds by 703; divide that number by your height in inches, then divide by your height in inches again. For example, a 130-pound woman who is 5 feet-4 inches tall has a BMI of 22.3, which is within a healthy, normal range.
If you’re BMI is within a normal range and you want to maintain your weight, you can use the calorie-per-pound method to estimate calorie needs. Harvard Medical School advises that sedentary women need about 13 calories per pound of body weight per day, moderately active women require about 16 calories per pound and women who exercise regularly at high intensities need about 18 calories per pound. For example, a 130-pound, moderately active woman needs about 2,080 calories a day to maintain her weight.
About 64 percent of women in the U.S. have BMIs of 25 or greater, which classifies them as overweight or obese, according to Weight Control Information Network. There are several ways to estimate your calorie needs for weight loss. If you eat 500 to 1,000 fewer calories each day, you’ll lose 1 to 2 pounds per week. The U.S. Department of Health and Human Services notes that most overweight women need 1,000 to 1,600 calories a day to achieve weight loss, depending on their current body weights and physical activity levels. The University of Washington estimates that eating about 10 calories per pound of your ideal body weight can help you reach your weight loss goal.
If your BMI is less than 18.5, ask your doctor if weight gain is appropriate. The trick to gaining weight healthfully is to increase muscle by exercising regularly — especially resistance training — and boost calories from nutritious foods. The Academy of Nutrition and Dietetics recommends eating an extra 200 calories per day to gain lean body mass. To avoid feeling too full or bloated when eating more food, get your extra calories from high-calorie, nutrient-dense foods, such as nuts, seeds, peanut butter, hummus, avocados or vegetable oils.
- National Heart, Lung and Blood Institute: Calculate Your Body Mass Index
- Harvard Medical School: Good Nutrition -- Should Guidelines Differ for Men and Women?
- Weight Control Information Network: Overweight and Obesity Statistics
- Academy of Nutrition and Dietetics: American Dietetic Association Publishes Evidence-Based Nutrition Practice Guidelines for Registered Dietitians
- U.S. Department of Health and Human Services: Aim for a Healthy Weight
- Academy of Nutrition and Dietetics: Build Muscle, No Steak Required
Erin Coleman is a registered and licensed dietitian. She also holds a Bachelor of Science in dietetics and has extensive experience working as a health writer and health educator. Her articles are published on various health, nutrition and fitness websites.