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How Many Calories Do Athletes Need?

 

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This is one of the most common questions I get as a registered dietitian. Over the next few weeks, I’m going to take you “inside the head” of an RD by showing you how to put together your own comprehensive nutrition plan.

In this post we will answer the question, “How many calories do athletes need?”  I’m really excited, so let’s get started!

Components of Total Energy Expenditure

The number of calories you need as an athlete is based on several factors such as body size, training load, and weight goals.

There are three important components that determine your daily energy expenditure.total-energy-expenditure

The first is basal metabolic rate (BMR). This is the number of calories your body needs to sustain normal activities while at rest. BMR accounts for the majority of our daily energy expenditure. Sometimes we call it metabolic rate.  Several factors influence our metabolic rate with the most important being lean body mass (skeletal muscle), genetics, age, and thyroid function.

Next, you must account for your physical activity. Exercise makes up roughly 25 to 35% of a person’s daily energy expenditure. Greater amounts of training obviously require more calories. For reference, we commonly say that 1 mile of running on the treadmill/road is equal to about 100 calories. It may be less if you’re smaller or more if you’re heavier.

The final component used in estimating total energy expenditure is the thermal effect of food. This reflects the amount of energy needed to digest the food you consume. To estimate this we typically tack on about 10% to an individual’s metabolic rate.

So to sum it up, we can say total energy expenditure = resting metabolism + physical activity + thermal effect of food.

 

Methods to Calculate Energy Needs

To cut through all of the clutter, I will provide you with two simple methods to estimate your energy needs. One method I call the ‘ballpark method’ while the other uses calories/kilogram of body weight/day.

  1. Ballpark method

BMR = multiply body weight x 10
+ calories from exercise
+ thermal effect of food (BMR x 10%)
Example:

A male athlete weighs 170 pounds, and is 6′ tall. He is a recreational runner who trains at a moderate intensity 5 days per week (30 miles/wk).

Using the ballpark method—

BMR = 1700 calories

Activity = 500 calories
TEF = 170

Total Energy Expenditure = 2400 calories

 

  1. Calories/kilogram of body weight/day

This is my favorite method because it is so easy. You categorize the athlete based on their level of training.

Using this method, I often calculate a range to be conservative. For this athlete I would use 34-36 kcal/kg/day.

Large TEE

1. To calculate from the example above you must convert pounds to kilograms
170 pounds / 2.2 = 77 kg

2. Multiply kilograms x target calories/kg/day

77 kg x 34 and  36 = 2600-2800 calories

That’s all there is to estimating Total Energy Expenditure! 

 

Summary

Remember total energy expenditure will vary based on a number of factors. It really should be adjusted based on the training you do each day. When estimating calorie needs, choose a method and stick with it! If you are already tracking your intake using an app like myfitnesspal.com then this is probably done for you.

This is NOT an exact science but will get you close enough. You could get all of these components tested in a lab using a metabolic cart. I talk about it in detail here. It is definitely NOT needed.

In my experience you can get within a “SNICKERS BAR” by using these simple calculations.

This gives you a starting point.  Now it’s your turn. Calculate your own energy needs and leave a comment below to let me know your numbers.

Reference: Chart adapted from Macedonio, M. & Dunford, M. (2009). The Athlete’s Guide to Making Weight: Optimal Weight for Optimal Performance. Champaign: IL: Human Kinetics.

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