Female Athlete Focus Part III: How many calories do I need?

Adequate energy consumption is a vital consideration for any athlete but especially for female athletes who may be more likely to restrict caloric intake for a variety of reasons.

Severe caloric restriction will adversely impact athletic performance, provide you with less of an opportunity to eat an adequate amount of vitamins and minerals, and could potentially lead to a host of other adverse health consequences. 

In order to help you determine your caloric needs, I am providing  the Dietary Reference Intake ( Institute of Medicine) calculation for what is known as your EER  (Estimated Energy Requirement). 

The EER is essentially a prediction of the  amount of calories you need to eat on a daily basis to maintain your current weight and is based on your activity level, age, sex, weight, height. 

If you are a 19+ years old female: 

EER= 354 – (6.91 x age [y]) + PA* x { (9.36 x weight [kg]) + (726 x height [m])  

If you are a 9-18 year old female:

EER = 135.3 – (30.8 x age [y]) + PA* x { (10.0 x weight [kg]) + (934 x height [m]) } + 25 

* if you are looking for the formulas for males, I have included them at the end of the post.

Legend 

Age –  your age in years

Weight –  your weight in kilograms.

Height – your height in metres. 

*PA- your physical activity coefficient. ( If age 19+  use PA= 1.45) ( If age 9-18 use PA= 1.56)

Sample Calculation: 

Samantha is 17 years old, 5’5 and  130 lbs. She is trying to determine the amount of calories she should consume during the soccer season to adequately fuel her body and maintain her current weight ( her EER). 

First, we have to convert her height to metres:  5’5 in metres is 1.65

Then, we have to convert her weight to kilograms: 130 lbs ( divided by 2.2 to get kg) = 59 kg

Because she is between age 9-18, we use PA= 1.56

So, EER = 135.3 – ( 30.8 x 17) + 1.56 x{ ( 10 x 59) + ( 934 x 1.65)} + 25 =  2960 calories a day

Samantha needs appx. 2960 calories a day to fuel her self and maintain her weight. 

The next question we need to answer is , how should these calories be distributed?

Macronutrients

The amount of calories you consume is important, but so is the macronutrient source you consume them from.  You can aim for the following macronutrient targets:

1. Carbohydrates:  Aim for 6-10 grams of carbohydrate per kilogram body weight

2. Protein: Aim for about 1.2-2.0 grams protein per kilogram body weight

3. Fat: Aim for 20-35% of your total energy expenditure to come from fat.

Sample Calculation 

Samantha weights about 59 kg and  knows she needs about 2960 calories a day. 

She needs to consume at least 6-10 grams per carbohydrate per kilogram of her body weight, ( I will use 8 here)  that is about 472 grams of carbohydrate a day or 1888 calories from carbohydrates ( 1 gram carbohydrate = 4 calories).

She needs to consume about 1.2-2.0 grams per kilogram body weight from protein which is about  ( I used 1.6 x 59= ~94.5 ) 94.5 grams a day of protein, or ( 1 gram protein = 4 calories) about 378 calories from protein.  

That leaves her about 694 calories from fat ( 694/2960 = 23%) which puts her at 23% of calories of fat which is within the healthy range. ( ~ 77 grams of fat, at 9 calorie per g)

Andy De Santis RD MPH 

*Formula for Males

9-18 years old

EER = 88.5 – (61.9 x age [y]) + PA x { (26.7 x weight [kg]) + (903 x height [m]) } + 25

19+ Years Old

EER = 662 – (9.53 x age [y]) + PA x { (15.91 x weight [kg]) + (539.6 x height [m])