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

Susan Bowerman, M.S., R.D., CSSD, CSOWM, FAND – Sr. Director, Worldwide Nutrition Education and Training October 12, 2022

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 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 body weight.

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

  • The standard recommended protein intake for endurance athletes is in the range of 0.5 to 0.6 grams per pound of body weight (or 1 to 1.3 grams per kilogram of body weight).
  • Strength athletes need a bit more and are advised to take in about 0.7 to 0.8 grams per pound of body weight (about 1.5 to 2 grams per kilogram of body weight). That means that a 180-pound (82 kilograms) athlete might need a minimum of about 90 to 110 grams a day to support endurance activity, or roughly 130 to 150 grams a day to support strength training.

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:

  • For most moderately active people, a well-balanced diet that supplies about half (45 to 55 percent) of the calories from carbohydrates should be adequate
  • Endurance athletes may need proportionately more, generally in the range of 55 to 65 percent of total calories.
  • Ultra-endurance athletes, such as those who participate in events lasting longer than four hours, need even more: up to 75 percent of their total calories from carbohydrates.

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

  • For general training, athletes are advised to take in 2.5 to 3 grams per pound of body weight (about 5.5 to 7 grams per kilogram).
  • Endurance athletes (runners, cyclists, swimmers) need more; the goal is 3 to 4.5 grams per pound of body weight (about 7 to 10 grams of carbohydrate per kilogram).
  • Ultraendurance athletes who engage in competitions that last for four hours or more may need 5 grams per pound of bodyweight or more (11 grams or more per kilogram).

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 they 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.