• Endurance athletes have an increase in protein oxidation (catabolism), meaning there is a higher protein turnover rate.
  • You must maintain a positive nitrogen balance.
  • Make sure that amino acids are spared for protein synthesis and not oxidized to assist in meeting energy needs.
  • Protein recommendations for endurance and strength-trained athletes range from 1.2 to 1.7 g/kg (0.5 to 0.8g/lb) body weight per day to maintain positive nitrogen balance.
  • These recommended protein intakes can generally be met through diet alone, without the use of protein or amino acid supplements.

BEST SOURCES: Eggs, fish, chicken, turkey, grass-fed beef, whey-isolate/concentrate/casein, plant proteins-chia/hemp/rice/pea, beans/rice, dairy foods-milk, yogurt, cottage cheese.


  • Fat intake should range from 20% to 35% of total energy intake.
  • Consuming <20% of energy from fat does not benefit performance.
  • Fat, which is a source of energy, fat-soluble vitamins, and essential fatty acids, is important in the diets of athletes. High-fat diets are not recommended for athletes (ketogenic diet).

BEST SOURCES: Olive, coconut, avocado, sunflower/safflower, flax, fish, raw mixed nuts.


  • Carbohydrate recommendations for athletes range from 6 to 10 g/kg (2.7 to 4.5 g/lb) body weight per day.
  • Carbohydrates maintain blood glucose levels during exercise and replace muscle glycogen.
  • The amount required depends upon the athlete’s total daily energy expenditure, type of sport, and environmental conditions.
  • Complex carbohydrates: steady, usable energy without stomach distress – Products containing simple sugars—typically sucrose, fructose, and/or glucose (dextrose)—must be extremely diluted or your body can’t digest them. That’s due to “osmolality,” a chemical measure of the concentration of a solution’s dissolved particles that can permeate a cell membrane.
  • complex carbohydrates can be digested readily at a much higher concentration. At a solution concentration of up to 18%, complex carbohydrates can pass efficiently from the digestive tract to the liver
  • While maltodextrin (glucose with a GI of 100) elevates blood sugar levels rapidly, it does not cause fluctuation in insulin levels the way simple sugars do.  SOURCES-corn, rice, potatoes, maltodextrin powder (cheap), and waxy corn maize.

BEST SOURCES: Fruits and vegetables-complex starches, whole grains-oatmeal, rice.

Vegetarian athletes may be at risk for low intakes of energy, protein, fat, and key micronutrients such as iron, calcium, vitamin D, riboflavin, zinc, and vitamin B-12. Vegetarians should take a multiple vitamin with a higher amount of iron and B vitamins.



Before exercise–A meal or snack should be relatively low in fat and fiber to facilitate gastric emptying and minimize gastrointestinal distress, be relatively high in carbohydrate to maximize maintenance of blood glucose, be moderate in protein, be composed of familiar foods, and be well tolerated by the athlete.

  • consume no more than 300-400 calories 3 hours before exercise.  Choose easily digested, complex carbohydrates, along with a small amount of protein and a little healthy fat.
  • Avoid high fiber, simple sugar, and acidic foods.
  • consuming high glycemic carbohydrates (simple sugars) within 3 hours of exercise can seriously hamper performance.  High insulin levels as a result of recent carbohydrate consumption lead to an increased rate of carbohydrate metabolism and carbohydrate fuel depletion. In simple terms: high insulin means faster muscle glycogen depletion.

Carbo loading—Make sure you do this right—4/5 days before an endurance event drop your carb. consumption 40-50% (eat protein, fat, and some fruit).  This will deplete muscle and liver glycogen stores.  Increase carb. consumption to 70-75% and this will rapidly increase muscle and liver glycogen stores to a higher level. 

During exercise–Primary goals are to replace fluid losses (electrolytes) and provide carbohydrates (approximately 30 to 60 g per hour) for maintenance of blood glucose levels.

  • For most athletes, 120-180 calories/hour is the ideal range.
  • Workouts/races of 2 hours or less: choose a fuel with complex carbohydrates.  Use simple sugars (glucose, sucrose, fructose, etc.) for events with short, intense bursts.  Simple sugars cause energy peaks and crashes, and must be mixed in weak concentrations for efficient digestion. Complex carbohydrates absorb at about three times the rate as simple sugars. Plus you get steady, reliable energy—no peaks and valleys.
  • Workouts or races of 2-3-hours, or more: Fuel primarily with complex carbohydrates, not simple sugars. Also, 10-15% of your fuel should come from protein, ideally soy, to help satisfy energy requirements and prevent muscle tissue catabolism.

After exercise-dietary goals are to provide adequate fluids, electrolytes, energy, and carbohydrates to replace muscle glycogen and ensure rapid recovery.

  •  Glycogen synthase is most active in the first 30 minutes after exercise, so consume 30-60 grams of carbohydrates and 10-20 grams of protein-3:1 ratio is preferred.
  • Depending on the intensity and length of the exercise, continue every 2 hours for 4 to 6 hours to adequately replace glycogen stores.
  • Protein consumed after exercise will provide amino acids for building and repair of muscle tissue.
  • Complex carbs might be the best choice if you are susceptible to hypoglycemia, weight gain, or blood glucose abnormalities.


  • Aim for a fluid intake of 0.5-0.6 fluid ounces of pure, clean water per pound of your body weight. That amount is in addition to the amount you drink during exercise.
  • Research has shown the optimal water intake for an average athlete during exercise to be about one water bottle (20-25 ounces) per hour
  • Without the proper levels of electrolytes, your body can’t carry out critical body functions including muscle contractions and the transmission of nerve impulses which affect performance.
  • Your body has very effective mechanisms for monitoring and conserving its stores of sodium. Consuming excess sodium interferes with these mechanisms.

Don’t consume JUST sodium- Consume electrolytes in amounts that do not override your normal body mechanisms.

  • If your body detects an increase in sodium from outside sources the hormone aldosterone signals your kidneys to stop filtering and recirculating sodium. Instead, they excrete sodium and then another hormone, vasopressin, causes fluids to be retained. The results include swelling and elevated blood pressure.
  • Your electrolyte intake must avoid detection by your body’s natural “radar system,” yet be potent enough to support body functions and prevent cramping.


  •  Athletes who restrict energy intake or use severe weight-loss practices, eliminate one or more food groups from their diet, consume high- or low-carbohydrate diets, and eat fast food/junk food, packaged foods of low micronutrient density are at the greatest risk of micronutrient deficiencies.



  • For female athletes, calcium intake is of particular concern. Excessive training—more than seven hours per week—may cause hormonal declines in young girls that can stop menstruation. This hormonal decline also compromises bone formation, possibly leading to premature, irreversible osteoporosis. Recent research shows that male endurance athletes of all ages experience testosterone deficits that also can cause osteoporosis.
  • Try and get close to 1200 mg/day. Drinking a cup of skim milk, for example, provides about 300 mg of calcium.  Each additional cup of skim milk consumed per day reduced runners’ incidence of developing a stress fracture by 62 percent–American Academy of Physical Medicine and Rehabilitation
  • Get more from Milk, yogurt, leafy greens, beans, fortified cereals


  • Magnesium is a component of more than 300 enzymes involved in energy metabolism.
  • This mineral is involved in adenosine triphosphate (ATP) production from fatty acid oxidation, post-contractile muscular relaxation, and bone remineralization. It is also involved in phosphatidylglycerol (DPG) production, which is important to red blood cell formation.  Low magnesium levels can acutely contribute to early fatigue, nausea, and muscle cramps. Chronic magnesium deficiencies can lead to increased osteoporosis risk and anemia.
  • Athletes lose magnesium through sweat and urine. This, combined with the fact that athletes’ diets are usually low in magnesium, generally leads to the need for supplementation. The recommended intake for endurance athletes is 500 to 800 mg daily.
  • Get more from Leafy greens, almonds, halibut, quinoa


  • This mineral is present in intracellular fluid and is responsible for regulating total body water and stabilizing controlled and automatic muscle contractions. It is also lost through sweat and urine.
  • With exercise, cells release potassium into the bloodstream and serum levels rise, possibly instigating fatigue.
  • Supplementing with potassium during training does increase markers of recovery, primarily serum lactate and muscle hydration, but does not aid performance.
  •  For post-activity replacement, athletes should take about 435 mg/hour of exercise or 200 mg/kg of weight loss. As much as 150 mg/hour during activity can be tolerated by most athletes.
  • Get more from Sweet potatoes, bananas, avocados, tuna


  • An hour of working out could deplete 5.7 percent of your level of this mineral, which helps red blood cells carry oxygen to muscles.
  • Losing too much of your stores can result in iron deficiency anemia, which causes fatigue and zaps your endurance during lengthy sessions.
  • Athletes who train for six or more hours per week often have iron-deficiency anemia and should be checked yearly for the condition. Female athletes who are unable to correct such mild anemia through diet can benefit from supplements.
  • Get more from Beef, eggs, spinach, broccoli, fortified cereals


  • Sodium helps cells retain water and prevents dehydration.
  • Salty sweaters (who notice a white film on their skin after a workout), heavy sweaters (who produce a high volume of sweat during exercise), people working out in hot, humid temperatures, and endurance athletes need to pay close attention to their sodium intake.
  • athletes should aim for 80 to 100 mg sodium per quart of hydrating beverage.


  • Loading up on carbs while limiting protein and fat causes deficient levels of zinc in up to 90 percent of athletes.
  • This can zap your energy and endurance. Likewise, recent research from the United States Department of Agriculture found that limiting zinc intake lessened cyclists’ oxygen uptake — leading them to fatigue more quickly.
  • This mineral aids in post-exertion tissue repair and in the conversion of food to fuel. Both male and female athletes have lower serum zinc levels compared with sedentary individuals. Studies correlate endurance exercise with periods of compromised immunity—zinc depletion may be one reason.
  • Get more from: Red meat, chickpeas, pumpkin seeds, quinoa


B Vitamins:

  • The body uses these to convert protein and sugar into energy and to produce red blood cells.
  • Athletes with low levels performed worse during high-intensity exercise, according to research published in the International Journal of Sport Nutrition and Exercise Metabolism.
  • The B-complex vitamins have two major functions directly related to exercise.
  • Thiamin, riboflavin, niacin, pyridoxine (B6), pantothenic acid, and biotin are involved in energy production during exercise.
  • Folate and vitamin B12 are required for the production of red blood cells, for protein synthesis, and in tissue repair and maintenance including the CNS.
  • Get more from Tuna, black beans, lentils, peanuts

Vitamin C:

  • Perhaps the most famous antioxidant, vitamin C offers a wide variety of health benefits, including protecting from infection and damage to body cells, helping produce collagen (the connective tissue that holds bones and muscles together), protecting your body from bruising by keeping capillary walls and blood vessels firm and helping in the absorption of iron and folate.
  • Because strenuous and prolonged exercise has been shown to increase the need for vitamin C, physical performance can be compromised with marginal vitamin C status or deficiency. Athletes who participate in habitual prolonged, strenuous exercise should consume 1000 mg of vitamin C daily.
  • DRI: 90mg (men), 75mg (women)
  • Good sources: citrus fruits (oranges, grapefruits, and tangerines), strawberries, sweet peppers, tomatoes, broccoli and potatoes, kale.


Michael Chase, MS, NTP

Nutrition Science and Dietetics

DISCLAIMER: The information provided in this post is for educational purposes only, and should not be construed as personal medical advice or instruction. No action should be taken based solely on the contents of this information. Individuals should consult appropriate health professionals on any matter relating to their health and well-being. The statements made in this informational document have not been evaluated by the Food and Drug Administration. Any product discussed is not intended to diagnose, treat, cure or prevent any disease.

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