Low energy in the Athlete

The most important nutrition advice for any athlete is to FUEL ADEQUATELY! Without the proper fuel, the body can not meet the demands requested for optimal physical performance. Proper fueling is important during performance day but also during recovery periods and even on rest days. Chronically under-fueling is referred to as Low Energy Availability (LEA) and when left unchecked, can lead to a syndrome called Relative Energy Deficiency in Sport or REDs. This syndrome has been shown to affect performance, injury rates, growth and hormone balance. Adequate energy with high amounts of physical exercise can be a challenge, especially when energy needs are high during growth spurts that occur in adolescence. The goal for energy balance is for energy expenditure to match energy consumption in a 24-hour period. Lived experiences of these challenges are shared below.

Julie - competitive swimmer

Julie is a 17-year old club swimmer. Julie swims daily for 2 hours each day and does resistance training for 3 hours a week. Participation at 3-day swim competitions approximately every 2 weeks is common.

Average 24-hour energy expenditure for Julie is approximately 2800 calories per day.

Average 24-hour energy consumption for Julie is based on the following patterns:

• Non-competition Days - three meals, two snacks averaging - 2500 calories per day

• Competition Days - Early morning high energy meal of 600 calories and snacks between events averaging 2300 calories per day.

Summary: Julie is still growing and menstrual cycle is inconsistent (6-7 cycles per year), recent complaints of fatigue, mood and swimming performance have reached a plateau. Julie has an energy deficit of approximately 1500-1700 calories per week. Julie is at high risk of hormonal and bone development complications.

Jacob - high school football player

Jacob is a 16-year old football safety. Daily practice with intense weight training. Games every Friday night during the season.

Average 24-hour energy expenditure for Jacob is approximately 3300 calories per day.

Average 24-hour energy consumption for Jacob is approximately 3000 calories per day based on three meals and three snacks each day.

Summary: Jacob is still growing as well as building muscle due to intense training. Jacob reports sleeping daily after practice due to fatigue and is very focused on weigh-ins and feels that fat gain may hinder speed on the field. Jacob is at high risk for injury, poor bone development, lowered testosterone levels and is at high risk for disordered eating.

Signs of LEA/REDs

• Fatigue

• Lack of motivation

• Sleep disturbance

• Decreased sports performance

• Decreased coordination

• Increased injuries

• Disruptions in menstrual cycle

• Decreased libido

• Frequent illness

• Body temperature changes (feeling cold)

• Depression

• Irritability

• Increased body focus

Dangers Associated with LEA/REDs

• Irregular menstruation

• Reduced hormone levels

• Low bone mineral density

• Decreased bone strength

• Low iron status (anemia)

• Urine incontinence

• Low blood glucose and insulin levels

• Elevated cholesterol levels

• Reduced blood flow (low blood pressure)

• Stunted growth

• Reduced function at muscle cells

• Reduced immune function

• Neurocognitive dysfunction (memory, decision making, spacial awareness)

• Mental health concerns (depression, anxiety, eating disorders and exercise addiction)

Prevention

Studies show that most athletes are unaware of their daily energy expenditure and lack nutrition knowledge to address the deficit. Education is the first step to both prevent and treat LEA/REDs.

• Determine daily calorie expenditure

  • Meet with a professional such as a Registered Dietitian who will consider the many factors that influence energy demands (body composition, growth phase, menstruation, sports demand).

  • Consider educating yourself with wearable technology. Accuracy of wearable total energy expenditure may be inconsistent but they do a good job of educating people on certain activities that impact needs, especially during off training periods such as typical daily activities away from sport.

• Learn how to fuel daily calorie expenditure with meals and snacks

  • Get education from a professional to learn the energy and nutrients of select food groups. General recommendations for adequate energy are >45 calories per kg of lean body weight per day.

    • Select high calorie, nutrient dense foods for each meal

    • Add snacks between meals that supplement energy intake.(nuts, seeds, dried fruit)

    • Consider the energy in drinks that are less filling but energy dense (smoothies, shakes).

• Do not restrict Carbohydrates

  • Studies have shown that inadequate carbohydrate intake is common in LEA/REDs

  • Glycogen stores are replenished with carbohydrates

  • General Carbohydrate recommendations for athletes is 5-12 g Carbohydrates per kg of body weight per day depending on training activities.

• Ensure micronutrients are met. If energy and carbohydrates are low then micronutrients are likely low. These micronutrients help cells produce the energy needed for the demand from sports. Many micronutrient needs increase as energy expenditure increases, putting athletes at risk for deficiency. The best way to meet micronutrients is eating a variety of fruits, vegetables, nuts, seeds and healthy fats. Many athletes report that smoothies combining higher calorie bases such as yogurt and milk mixed with lower calorie vegetables allow for an easy to digest, high energy, nutrient dense drink.

• Shakes and bars designed for athletes are not required and may be discouraged for some individuals so using a whole food first approach is best. If you feel you need to rely on commercial pre-prepared foods, consider getting advice from a Registered Dietitian.

Sample Daily LEA preventive meal and snack plan

Approximately: 2500 Calories, 280 g Carbohydrates, 100-110 g Protein

Meal 1: Breakfast (~600 calories)

• Loaded Oatmeal: 1 cup rolled oats cooked with 4 oz milk of choice, 1 sliced banana, and 1 oz. of chopped walnuts, teaspoon of dried fruit.

• Protein Side: 1 large hard-boiled or scrambled egg with a slice of toast.

Meal 2: Mid-Morning Snack (~350 calories)

• Cottage Cheese Bowl: 1 cup low-fat cottage cheese

• Fruit: 1 medium apple or fruit of choice, sprinkle of pumpkin seeds

Meal 3: Lunch (~600 calories)

• Protein: 3-4 oz grilled chicken breast, pork or fish

• Grains: 1.5 cups cooked brown rice

• Vegetable: 1 cup steamed broccoli with 1 teaspoon extra-virgin olive oil

Meal 4: Pre- or Post-Workout Snack (~350 calories)

• Smoothie: 1 cup whole milk or greek yogurt, and 1 cup mixed berries, 1 cup of leafy greens, 1 tsp of honey

Meal 5: Dinner (~600 calories)

• Protein: 4–5 ounces baked salmon or lean steak

• Grains: 1 cup cooked quinoa or sweet potato wedges

• Vegetable: Large mixed green salad with olive oil and vinegar dressing, plus 1 whole-grain dinner roll

Summary Key Points:

• Energy expenditure during athletic performance requires adequate energy for performance and health.

• Daily low energy compared to demands can build up and lead to loss of cellular functions to build bone, tendons and muscle that cause injury, illness and hormone dysfunction.

• Athletes should educate themselves on their unique energy demands and daily needs and plan nutrient dense meals and snacks to prevent LEA/REDs.

References:

Gallant TL, Ong LF, Wong L, Sparks M, Wilson E, Puglisi JL, Gerriets VA. Low Energy Availability and Relative Energy Deficiency in Sport: A Systematic Review and Meta-analysis. Sports Med. 2025 Feb;55(2):325-339. doi: https://doi.org/10.1007/s40279-024-02130-0

Ihalainen JK, Mikkonen RS, Ackerman KE, Heikura IA, Mjøsund K, Valtonen M, Hackney AC. Beyond Menstrual Dysfunction: Does Altered Endocrine Function Caused by Problematic Low Energy Availability Impair Health and Sports Performance in Female Athletes? Sports Med. 2024 Sep;54(9):2267-2289. doi: https://doi.org/10.1007/s40279-024-02065-6

Whitney KE, Holtzman B, Parziale A, Ackerman KE. urinary incontinence is more common in adolescent female athletes with low energy availability. Orthop J Sports Med. 2019 Mar 29;7(3 Suppl):2325967119S00115. doi: https://doi.org/10.1177/2325967119S00115

Lodge MT, Ward-Ritacco CL, Melanson KJ. Considerations of Low Carbohydrate Availability (LCA) to Relative Energy Deficiency in Sport (RED-S) in Female Endurance Athletes: A Narrative Review. Nutrients. 2023 Oct 20;15(20):4457. doi: https://doi.org/10.3390/nu15204457