How do you calculate your caloric needs as a CrossFit athlete?

To perform at your best as a CrossFit athlete and make progress in your training, it is essential to know your own caloric needs precisely and ensure that your diet meets those requirements. In this article, you will learn which formula to use to calculate your daily caloric expenditure and how to verify whether the calculated value matches your actual caloric needs.

What is a calorie

Before we delve into calculating and verifying caloric expenditure, it is important to first understand what a calorie actually is. The term "calorie" is often used in the context of nutrition and energy consumption, but what is really behind it?

Definition: A calorie is a unit of measurement for energy. More precisely, a calorie is the amount of energy required to raise the temperature of 1 gram of water by 1 degree Celsius. In nutritional science, however, we usually speak of "kilocalories" (kcal), which correspond to 1,000 of these small calories. So, when we talk about a calorie in nutrition, we are actually referring to a kilocalorie.

Calories in food: Food contains macronutrients – carbohydrates, proteins, and fats – that provide the body with energy in the form of calories. This energy is needed to support all of our body's functions, from basic processes like breathing and digestion to physical activities like training and sports.

• Carbohydrates: 1 gram of carbohydrates provides about 4 kcal.
• Proteins: 1 gram of protein provides about 4 kcal.
• Fats: 1 gram of fat provides about 9 kcal.

These calories from food are used by your body to provide the energy you need for everyday activities and, in particular, for athletic performance like CrossFit.

To get rid of 1 gram of body fat, you need to save or burn about 8 kcal.

Why is caloric requirement important

For CrossFit athletes and other sportspeople, the right caloric intake is crucial. Too few calories can result in a lack of energy for intense workouts, which impairs your performance and recovery. Too many calories, on the other hand, can lead to unwanted weight gain.

Use this formula to calculate your daily caloric requirement

Your caloric requirement is composed of two main components:

Basal Metabolic Rate (BMR): This is the amount of calories your body needs at rest to maintain vital functions such as breathing, heartbeat, and digestion.

Active Metabolic Rate: This is the additional energy you burn through physical activity.

The calories for the BMR can be calculated using various formulas, with the Mifflin-St Jeor formula considered one of the most accurate:

Mifflin-St Jeor formula:

• Men: BMR = 10 x weight in kg + 6.25 x height in cm – 5 x age in years + 5
• Women: BMR = 10 x weight in kg + 6.25 x height in cm – 5 x age in years - 161

This formula provides a solid basis for calculating your basal metabolic rate in calories. However, athletes or very active individuals require significantly more energy.

The active metabolic rate depends on your activity level. Since CrossFit training is intense, you should use a higher activity factor for the calculation:

• Lightly active (1-3 days/week): BMR × 1.375
• Moderately active (3-5 days/week): BMR × 1.55
• Very active (6-7 days/week, intense CrossFit training): BMR × 1.725
• Extremely active (daily CrossFit training, physically demanding job): BMR × 1.9

Example: A 30-year-old male athlete who weighs 80 kg and is 180 cm tall has a BMR of about 1,800 kcal. With an activity factor of 1.725 (very active), his total daily caloric requirement would be about 3,105 kcal.

Verifying actual caloric expenditure

It is not enough to just calculate your caloric expenditure. You must ensure that it matches your actual needs. Here are a few methods to verify this:

Weight control: Weight is the most direct indicator of whether you have estimated your caloric needs correctly. Keep a record of your weight for 2-4 weeks. It is important that you always weigh yourself at the same time. Best in the morning after using the restroom:

• Constant weight: Your caloric intake matches your expenditure.
• Weight loss: You are consuming fewer calories than you burn – you may need to eat more.
• Weight gain: You are consuming more calories than you burn – you may need to eat less or increase your activity.

It should be mentioned here that body weight always fluctuates slightly, and when analyzing the log, it is important to pay attention to trends, not just absolute values.

Body composition: In addition to weight, body composition can also provide important clues. A reduction in body fat percentage while weight remains the same can indicate that you are losing fat and building muscle – a sign that your caloric expenditure might be higher than the calculations suggest. This may also be desired for a certain period. Too much fat is just unnecessary baggage.

Professional methods: If you need a more precise measurement of your caloric expenditure, there are advanced methods that can help you.

• Indirect calorimetry: This method measures oxygen consumption and carbon dioxide production to accurately calculate caloric expenditure. It is particularly useful for athletes who need precise data to optimize their nutrition.
• Advice from a nutritionist: A nutritionist specializing in sports nutrition can help you optimize your diet based on detailed analyses and your specific training program.

Conclusion

For you as an athlete, it is crucial to know your own caloric expenditure precisely and ensure that your diet meets this requirement. By calculating your BMR and active metabolic rate, as well as regularly checking via weight control, food logging, and body composition, you can ensure that you are fueling your body optimally. Long-term observation and, if necessary, professional support will help you reach your athletic goals and maximize your performance.