How to Estimate Calorie Needs for Dieting Athletes - dummies

How to Estimate Calorie Needs for Dieting Athletes

By Jane Kirby, The American Dietetic Association

If you are a dieting athlete, simply cutting your calories will impact your performance. Your focus should be lowering the percentage of body fat you carry. If you know what your weight-loss goal is, you can calculate your total daily calories and the ideal amounts of carbohydrate, protein, and fat.

Cutting calories drastically impairs your performance. Therefore, the recommendation is to maintain weight (but shift your percentage of fat to lean) while you’re training and use the “off season” for weight loss.

If you must lose while training (because you’re a year-round athlete), weight loss of 1/2 to 1 pound a week is the recommendation. Losing weight more quickly causes loss of muscle glycogen (the form of energy that is stored in the muscles) and muscle tissue loss as well.

Rapid weight-loss diets that are low in carbohydrates are particularly dangerous for athletes. Most of these diets cause water loss, which can lead to impaired cardiac function, inability to maintain body temperature, and muscle cramping.

  1. To calculate your caloric needs first find your Basic Metabolic Rate (BMR).

    Your BMR indicates the number of calories you need to maintain heartbeat and breathing.

How Many Calories Your Body Needs Per Day for Basic Energy Needs
Age Use This Equation to Calculate Your BMR
Men *
18 to 30 [15.3 x weight (in kilograms)] + 679
30 to 60 [11.6 x weight (in kilograms)] + 879
Older than 60 [13.5 x weight (in kilograms)] + 487
Women *
18 to 30 [14.7 x weight (in kilograms)] + 496
30 to 60 [8.7 x weight (in kilograms)] + 829
Older than 60 [10.5 x weight (in kilograms)] + 596
  1. Then multiply it by the activity factor that applies to you in the following table.

    Most athletes fall in the heavy range for physical activity. Therefore, their BMR would be multiplied by 1.9–2.1.

Activity Factors
Exercise Level Description Factor
Very Light Extremely sedentary, largely bed rest 1.2–1.3
Light No planned activity, mostly office work 1.5–1.6
Moderate Walking, stair climbing during the day 1.6–1.7
Heavy Planned vigorous activities 1.9–2.1

The recommended weight loss for athletes in training is 1/2 to 1 pound per week.

So, here’s the breakdown:

  • Calorie deficit per week: 3,500 (calories in a pound) x 1/2 to 1 = 1,750–3,500

  • Calorie deficit per day: 1,750–3,500 ÷ 7 (days in a week) = 250–500