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.
Healthy fats: Daily consumption of 0.45 grams of fat per pound of body weight
Healthy fats, such as polyunsaturated and monounsaturated fats, are an essential nutrient for young athletes, and not getting enough can impair performance. Fats should make up 20 to 35 percent of total energy intake. Some fats can come from animal sources as part of meeting protein goals, but trans fats should be limited. Healthy fats are found in nuts and seeds, such as almonds, walnuts, pumpkin seeds, flax seed and chia seed. Healthy oils include olive oil, coconut oil, flax oil and sesame oil. Avocados and fatty fish, such as salmon and tuna, are also good sources of healthy fats.
Omega-3s: Vital for health
Omega-3 fatty acids are an especially important category of fats. Omega-3 fatty acids are vital for all cells to function properly.
Because the body doesn't produce these compounds, however, the only way to obtain omega-3 fatty acids is through the diet or dietary supplements. Two omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are found primarily in fatty fish, such as salmon, tuna and trout. Unfortunately, most individuals don't consume enough of the right kinds of fish to provide sufficient amounts of omega-3s. Omega-3 fatty acids from fish are available as dietary supplements.
Research shows that omega-3 fatty acids from fish oil can support cardiovascular health. In addition, they can help maintain proper brain and nerve function and provide support for healthy joints, skin and eyes. Omega-3s can also help alleviate muscle soreness and stiffness brought on by exercise. One study found that DHA significantly reduced muscle soreness and improved range of motion after bicep curls.
Important nutrients to consider
Some people who eat a healthy diet still might not be getting enough vitamin D, iron and calcium. In addition to taking a multivitamin/mineral supplement, consider taking these three supplements.
Vitamin D. Vitamin D deficiencies are common in the United States. Many children and adults don't consume the recommended daily value of 600 international units (IU) of vitamin D.
The body needs vitamin D to absorb calcium. A lack of vitamin D can weaken bones, which increases the risk of fracture. In addition to bone health, vitamin D is essential to promote muscle mass. One study found that low vitamin D levels affected muscle strength in U.S. college athletes. Athletes with lower vitamin D levels performed worse on several tests of muscle strength compared to athletes who had higher levels of vitamin D.
Good sources of vitamin D include oily fish, such as tuna and sardines, as well as egg yolks and fortified milk. Sunlight also contributes to the body's production of vitamin D. Many experts recommend that female adolescent athletes take a daily vitamin D supplement of 500 to 1,000 IU, or even more if a deficiency has been identified. A blood test for vitamin D levels is easily accessible.
Many nutrition experts also recommend taking vitamin K along with vitamin D. In addition to vitamin K supporting bone health, it also helps direct calcium out of the soft tissues and into the bone where it belongs.
Calcium. Calcium builds healthy bones and teeth. A diet low in calcium can lead to early bone loss and increased fracture risk, in addition to causing muscle cramping.
It's not always easy to get enough calcium through diet alone, particularly for people who avoid dairy products. In addition to dairy products, other good dietary sources of calcium include almonds, broccoli, kale, canned salmon with bones, sardines and soy products, such as tofu.
Children ages 9 to 18 should consume at least 1,300 milligrams (mg) of calcium daily. For adults ages 19 to 50, the recommended amount is 1,000 mg of calcium daily. Many children and teens don't get enough calcium, however. On average, adolescent girls consume only 900 mg a day, compared to 1,200 mg a day for adolescent boys. To put things in perspective, an 8-ounce glass of milk provides 300 mg of calcium.
Nutrition experts recommend taking magnesium along with calcium. Like vitamin K, magnesium helps prevent calcium from accumulating in the soft tissues such as the kidneys (forming kidney stones) and directs it to the bones.
Iron. This metallic element is needed to form red blood cells. It is an integral part of the hemoglobin molecule, which is the protein in the red blood cells responsible for carrying oxygen from the lungs to the tissues.
Iron deficiency is fairly common in female adolescents, whether they are athletes or not. In one study, 40 percent of female adolescent participants were iron deficient. Iron deficiency can occur for several reasons, including blood loss during menstruation, poor diet, heavy training, intestinal bleeding and insufficient iron absorption. A significant iron deficiency can cause anemia. Its usual symptoms are pale skin, fatigue, weakness, shortness of breath and dizziness. A simple blood test can identify anemia and iron deficiency.
Two types of iron are found in the diet — heme and nonheme. Heme iron is better absorbed than nonheme iron. Beef and other red meats, poultry, and seafood are the primary sources of heme iron. Nonheme iron is found in beans, lentils, spinach and broccoli. In the case of iron deficiency, supplementation might be needed — with the amount to be determined by a health care professional depending on the extent of the deficiency.
Plan the day for healthy eating
Good nutrition during a hectic day usually requires planning and effort. Teens often need help and input from parents and coaches — and possibly a health care professional. Follow these tips to make sure a young athlete's daily nutritional needs are being met.
Nov. 16, 2016
See more In-depth
- Eat a healthy breakfast. Don't expect a menu of breakfast ideas to materialize at 7:00 a.m. with 10 minutes to get out the door. Plan ahead with a few easy-to-fix breakfast ideas that incorporate carbohydrates, protein and healthy fats. Ideas include a bowl of whole-grain breakfast cereal with an extra glass of milk, or two eggs on whole-grain toast. Top off either of these with an apple or other fruit and chopped almonds or walnuts for heading out the door.
- Solve the healthy lunch problem. If school lunches don't cut it, then plan ahead and pack a lunch or pack a half-lunch to supplement things that are acceptable on the school menu. Protein sources can include milk or Greek yogurt from school, or leftover meat from home. Carbohydrates come in many lunch-ready forms, such as slices of whole-grain bread or a whole-grain bagel. Fruits, vegetables, seeds and nuts are quick to pack and don't need refrigeration.
- Have snacks at the ready. To satisfy midmorning or midafternoon hunger pangs, a large bag of dried fruit or nuts can be stashed in a locker.
- Have an after-practice plan. Within the first hour after a practice or game, depending on its duration and intensity, be prepared to consume up to one-half gram of carbohydrate per pound of body weight — and 20 to 25 grams of protein to stimulate muscle recovery. This could be as part of or in addition to a nutritious dinner. Good choices include Greek yogurt with fruit, a protein shake or a homemade protein bar.