How Many Calories Do I Need to Lose Weight?
Women need approximately 1,800 to 2,000 calories per day to get our essential nutrients without gaining weight. Of course this will vary based on your height and activity level. Some petite women who are 5 feet tall may need fewer calories, while women who are taller than 5’10 may need more. Likewise, very active women may need 2,400 calories a day to sustain good health, while sedentary women may need only 1,400 calories.
Before you can figure out your personal calorie budget, you should know your Ideal Body Weight (IBW) range. Should you aim to maintain your weight, lose, or gain? Once you figure this out, you can use what nutritionists call the Quick & Dirty Method to get your calorie budget. It takes into account your current weight, weight goals, and physical activity status. Now grab your calculator.
Step 1: Calculate your Ideal Body Weight.
Women: 100 pounds for the first 5 feet plus 5 pounds for every additional inch, +/- 10%.
Men: 110 pounds for the first 5 feet plus 5 pounds for every additional inch, +/- 10%.
Example: If Stacy is 5’ 7’’ tall, her IBW is 100 + (5 x 7) = 135 pounds; 135 +/- 10% = approximately 120-150 pounds.
Step 2: Calculate your personal daily calorie budget.
First convert your current weight into kilograms by dividing your weight in pounds by 2.2. For example, if Stacy is 130 pounds, she is 59 kg (130 / 2.2 = 59). Base your calorie budget on the following criteria:
40 to 45 calories per kg of body weight to gain weight and/or for intense physical activity (i.e. you are training for an event such as a race or triathlon)
30 to 35 calories per kg of body weight for weight maintenance and/or moderate physical activity (i.e., 4 to 5 days per week of approximately 30 minutes of cardio on the treadmill or elliptical machine)
20 to 25 calories per kg of body weight for weight loss and/or low physical activity (i.e., you rarely go to the gym or engage in formal exercise)
So, going back to our example with Stacy, if she is looking to lose weight, and she is not working out, she should be eating roughly in the range of: 59 kg x 20 calories to 59 kg x 25 calories = 1,180 to 1,475 calories per day. Now let’s say Stacy embarks on an exercise program and is taking a class that burns approximately 400-500 calories per class. On the days she takes that class, she can increase her calorie budget by that amount and still lose weight. Whether she eats on the lower end or the higher end of this calorie budget will determine how quickly she wants to lose weight. She should aim to lose anywhere from 1/2 lb to 2 lbs per week for sustainable and long term weight loss.
Fitness Tip: Calculate your Daily Calorie Budget and use a meal journal to be sure you are within your budget for your weight loss goals.