Calories and nutrients to fuel sports performance

Getting enough calories and nutrients is crucial for sports and for overall health and wellness.

It's easy to get mired in the details of sports nutrition, which is why it's good to also look at the big picture of simply getting enough calories to meet energy needs. This involves getting adequate amounts of the major energy groups: carbohydrates, protein and healthy fats.

Optimal energy intake is crucial not only for sports, but also for overall health and wellness. It helps athletes optimize their response to training and improve their performance.

In contrast, inadequate energy intake can reduce or negate the benefits of training because it interferes with performance output and impairs recovery. In addition, when not enough calories are consumed to meet activity demands, the body will break down fat and muscle tissue to use as fuel, resulting in a loss of both strength and endurance. Not getting enough calories can also:

  • Lead to a weakened immune system, which increases the risk of getting sick
  • Lead to nutritional deficiencies that can impair cognitive function and brain health, as well as compromise bone health and other bodily functions

In addition to needing adequate calories, athletes can also be at risk of having deficiencies of several specific nutrients.

How many calories are enough?

How much is enough when it comes to meeting the energy needs of young athletes? Many variables are involved in answering this question. Individual differences in age, intensity and duration of activity, and body size and composition are all factors to consider when looking at calorie needs.

The recommended daily calorie intake for female athletes is approximately 20 to 23 calories per pound of body weight (45 to 50 calories per kilogram), or even higher for athletes who are building lean muscle mass. It's best to work with a health care professional, such as a registered dietitian or a sports nutritionist, to accurately determine how much energy an individual athlete needs to achieve energy balance.

Signs of inadequate energy intake in girls and young women include:

  • Body mass index (BMI) lower that 18.5
  • Body fat percentage below 12 percent
  • Delayed, irregular or stopped menstruation
  • Low bone mineral density, which can be indicated by frequent stress fractures

Low energy intake is not always obvious. Girls who are overweight can be energy deficient. In addition, it's possible to be energy deficient and still maintain one's weight. Or girls might lose weight initially, then stop losing weight but still continue to be energy deficient.

Energy balance starts with good nutrition

The key to maintaining energy balance is to consume sufficient calories through a healthy diet. Three nutrient categories make up the foundation of a healthy diet.

Carbohydrates: Daily consumption of 3 to 5 grams of carbohydrate per pound of body weight

Carbohydrates are the primary energy source for exercise and should account for 50 to 60 percent of a young athlete's total energy intake. Athletes should eat carbohydrates before and after exercise. Carbohydrate-containing foods that are minimally processed, are high in fiber and have less added sugar are best. Examples include fruits and vegetables, beans, and whole grains such as high-fiber cereal, 100 percent whole-grain bread, brown or wild rice, oatmeal, popcorn, and low-sugar granola bars.

Protein: Daily consumption of 0.5 to 0.8 grams of protein per pound of body weight

Protein builds and repairs muscle, helps muscles recover after exercise, and improves strength. Protein intake should range from 10 to 35 percent of total energy consumption. The easiest and most effective way to achieve protein requirements is through food. Animal sources of protein include skim or 1 percent milk, Greek yogurt, cottage cheese, eggs, lean meats, and fish. Nonanimal protein sources include beans, lentils, nuts, seeds, soy foods or soy milk. It can be difficult to meet protein needs on a vegetarian diet, so supplementation with a protein powder might be necessary. When taking a protein supplement, limit the daily amount to no more than 0.6 grams per pound of body weight.

Nov. 16, 2016 See more In-depth