Energy Availability & Relative Energy Deficiency
Energy availability refers to the amount of dietary energy remaining for the body’s physiological functions after accounting for energy expended during exercise. Relative energy deficiency occurs when this available energy is insufficient to maintain optimal health, performance, and bodily functions. This deficiency can negatively impact metabolic rate, menstrual function, bone health, immunity, and cardiovascular health, commonly affecting athletes or individuals with high physical activity and inadequate nutritional intake.
Energy Availability & Relative Energy Deficiency
Energy availability refers to the amount of dietary energy remaining for the body’s physiological functions after accounting for energy expended during exercise. Relative energy deficiency occurs when this available energy is insufficient to maintain optimal health, performance, and bodily functions. This deficiency can negatively impact metabolic rate, menstrual function, bone health, immunity, and cardiovascular health, commonly affecting athletes or individuals with high physical activity and inadequate nutritional intake.
💡 Key Takeaways
- Define energy availability and relative energy deficiency, and why they matter for health and performance.
- Learn how to estimate energy availability: calories consumed minus calories burned in exercise.
- Identify the health and performance consequences of chronically low energy availability (e.g., hormonal disruption, menstrual changes, bone health, immunity, fatigue).
- Recognize common signs and at-risk groups (athletes, dieters, people with high energy expenditure) to screen for RED.
- Explore practical strategies to optimize energy availability through adequate intake, nutrient-dense foods, meal timing, and safe training adjustments.
❓ Frequently Asked Questions
What is energy availability and how is it calculated?
Energy availability (EA) is the energy left for the body's essential functions after accounting for exercise energy expenditure. It is commonly estimated as EA = (Energy Intake − Exercise Energy Expenditure) / Fat-Free Mass (kcal/kg/day). Adequate EA is usually above about 45 kcal/kg FFM/day; low EA is around 30 kcal/kg FFM/day or less, which may risk RED-S.
What does relative energy deficiency in sport (REDS) mean and why is it important?
REDS (or low energy availability) means the body isn’t receiving enough energy to support health and performance. It can affect menstrual function, bone health, immunity, mood, and training adaptation.
What are common signs and symptoms of low energy availability?
Menstrual irregularities, bone stress injuries, frequent illness, fatigue, poor concentration, decreased training response, weight changes, and mood changes.
How can athletes improve energy availability safely?
Increase daily energy intake to meet training needs, especially around workouts; choose energy-dense, nutrient-rich foods; spread meals throughout the day; consider adjusting training load if needed; consult a sports nutritionist for personalized guidance.