Energy availability (EA) plays a critical role in both performance and recovery. Yet in weight- and aesthetic-driven sports, athletes, particularly women, often adopt restrictive eating patterns. These habits can compromise EA, leading to diminished performance and slower recovery.
Currently, two methods are the go-tos for determining EA. The first, calculating an individual’s Resting Metabolic Rate RMR ratio, which is the comparison of an individual's measured Resting Metabolic Rate (RMR) to their predicted RMR calculated from personal metrics like height, weight, and age. The second is a comparison of calculated caloric intake and fat-free mass (FFM).
Thresholds for low energy availability have been established. An RMR ratio of <0.9 and a calculation of <30 kcal/kg FFM/d are considered to be indicative of low energy availability.
This week, The Research Desk examines a 2025 study comparing the measurement of these two popular methods.
PMID: 40641654
Vitality Takeaway
Previous research from 2013 has shown that only 9% of female collegiate athletes met their energy needs.
In this study, seventy-seven highly active females (including NCAA D1 athletes and recreationally active individuals) underwent assessments of body composition, dietary intake, and resting metabolic rate (RMR) ratio.
Researchers found:
- 63% of participants met criteria for low EA (<30 kcal/kg FFM/d).
- Across the entire sample, mean energy availability was below the threshold for low EA.
- 19% of the sample had a low RMR ratio (below 0.9).
- 14% of participants had both low EA and a low RMR ratio.
- Carbohydrate intake was below typical recommendations for athletes
Researchers suggest that RMR ratio assessment may be a more sensitive indicator of energy availability.
This study confirms previous data suggesting that active females are not consuming adequate amounts of carbohydrates and calories in general. And while there are multiple efforts to educate athletes, coaches, and healthcare providers about energy availability, this research highlights the need for continued efforts.
Vitality Application
Energy availability is crucial for optimal performance and health. Proper fueling has the potential to influence every functional and performance area in the Vitality catalogue. While that may sound like an overstatement, it isn’t.
By supporting optimal energy availability, every aspect of performance receives optimal support. Continued educational efforts can help athletes and support staff understand its utmost importance, especially when considering female athletics.
Recommendation: Depending on body composition goals, maintain an energy availability of at least 30 kcals/kg of fat-free mass and an RMR ratio of at least 0.9.
Explore the Vitality Encyclopedia to learn more about these topics.
