How to Estimate Calorie Needs for Dieting Athletes

Gut Health For Dummies

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.

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

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

About This Article

About the book author:

Jane Kirby, RD is a registered dietitian and member of the American Dietetic Association. She is the food and nutrition editor of Real Simple magazine and owner of The Vermont Cooking School, Inc^TMin Charlotte, Vermont. Jane is the former editor of Eating Well magazine and the food and nuitrition editor for Glamour. She served on the dietetics staff of the Massachusettes General Hospital in Boston, where she completed graduate work in nutrition. She holds a Bachelor of Science degree from Marymount College.

The American Dietetic Association is the world’s largest group of nutrition and health professionals. The ADA serves the public by promoting optimal nutrition, health, and well-being.