Know Your Macros: How Protein, Carbs, and Fat Fuel Athletic Performance

People often ask me, “What is the recommended calorie intake from carbs?,” or “What percent of my diet should be protein?” For most people, we generally recommend a 40-30-30 distribution for carbs, protein, and fat, respectively, but for those with athletic goals, their requirements are more personalized.

For athletes and active individuals, calculating the right balance of macronutrients is important as it could impact their training and sports performance.

Calculating Macros for Sports, Exercise, and Athletic Performance

Carbohydrates, protein, and fat are referred to as dietary macronutrients. “Macro” means large, and we need relatively more of these nutrients than the micronutrients (vitamins and minerals). We generally get our micronutrients along with macronutrients.

The amount of the different macros that athletes need varies on the type and intensity of activity they are engaging in. Macro percentages for strength training, for example, differ somewhat from those for endurance runners.

Here’s a quick rundown on what athletes need to know about their macros.

How Much Protein Do Athletes Need?

Protein supports exercise, but not by serving as a primary fuel source. It has too many other more important functions in the body. Of course, dietary protein is needed for muscle repair and growth, but it is also needed to make enzymes – proteins that assist with thousands of chemical reactions that take place in the body –  including the production of energy from food.

Hormones, such as insulin and glucagon that help to regulate the levels of sugar in your blood, are made from the amino acids in the proteins that you eat. And, your body uses the protein in your diet to manufacture antibodies – proteins that help your body fight infection.

Recommended protein intakes are often expressed as a percentage of total calories, but sports nutritionists prefer to calculate protein needs for athletes according to bodyweight.

It should make sense that athletes require more protein than sedentary people since they generally have more muscle mass.

Ideally, though, protein intake would be tailored to the amount of lean body mass (LBM) you have since bodyweight alone doesn’t tell the whole story. Your LBM comprises all your bodyweight that isn’t fat – your muscles, bones, organs, tissues, and water – and can vary quite a bit among individuals of the same body weight.

Body composition testing can determine your LBM, and athletes are advised to take in about 1 gram of dietary protein for each pound of lean mass. Strength athletes may need a bit more – up to 2 grams per pound of lean mass.  By using this tailored approach, dietary protein intake can provide a good match to support the athlete’s amount of lean body mass.

Recommended Carbohydrate Intake for Athletes

Carbohydrates serve as the main source of fuel during exercise, which is why it’s so important for athletes to consume adequate amounts. This ensures that they have readily available carbohydrate stores in the muscle, liver, and bloodstream.

Carb requirements will vary based on activity:

Sports dietitians prefer to calculate carbohydrate needs according to bodyweight rather than a percentage of calories because it gives the athlete a specific intake goal:

The Role of Fat Intake for Athletes

Dietary fats supply the body with essential fatty acids.  They’re termed essential because the body can’t make them, so you have to come from the diet. They’re an important part of the structure of every cell in your body and serve as a valuable energy source during activity.

Rather than suggesting a precise amount of fat for athletes, sports nutritionists usually recommend an intake of around 25 to 30 percent of their total calories: the amount that’s recommended for the general population.

Since carbohydrate and protein intakes are more specific, once those intake targets are met, fat intake tends to naturally fall within the recommended range. And, like the general population, athletes are encouraged to select mostly unsaturated fats from foods like nuts, seeds, avocados, fatty fish, and oils such as seed oils (like canola, safflower, or sunflower) and olive oil.

While carbohydrates are considered the body’s primary fuel source, the body uses both carbohydrates and fat as fuel, depending on the intensity and duration of the activity. When exercise intensity is light to moderate, fat supplies about half of the body’s energy needs – especially as the duration increases. For example, after jogging for more than 20 minutes at a moderate pace, fat becomes increasingly more important than carbohydrates for sustaining activity.

Keeping your macros in the right balance is critical for good performance, and athletes would be wise to avoid dietary trends that upset this balance.

Susan Bowerman, M.S., RD, CSSD, CSOWM, FAND –Sr.Director, Worldwide Nutrition Education and Training

Susan BowermanM.S., RD, CSSD, CSOWM, FAND – Sr. Director, Worldwide Nutrition Education and Training

Susan Bowerman earned a B.S. in biology with distinction from the University of Colorado, and received her M.S. in food science and nutrition from Colorado State University. She is a registered dietitian, holds two board certifications from the Academy of Nutrition and Dietetics as a certified specialist in sports dietetics, and a certified specialist in obesity and weight management, and is a Fellow of the Academy.