Energy Availability
Well done! you have just entered the era where sports nutrition is becoming a lot more understood and having huge positive outcomes around health and performance in the world of endurance sport
For years we grappled with concepts that were hard to deliver and were perhaps based on basic models used for weight loss in the general population.
We have also now seen a large push forward in accessible sports dieticians able to deliver cutting edge information that athletes can use easily.
My role as a coach in this area has evolved also. It was previously an area I felt best left to experts, but now my role is clear …
I have to be able to deliver up to date and relevant information to the athletes I work with to allow them to have both improved health and performance.
The Energy Availability Model
History
As far back as 1994 this model of having the correct amount of energy available to allow for things such as recovery, hormonal health & bone health was introduced. It has it’s history in fact in the women’s sport domain where menstrual dysfunction was all too common. Coaches driving weight loss was a thing and whilst we look back with horror, it was just a deeply embedded culture. Thankfully, one that’s quickly disappearing.
What started as a clinical health model is now a performance tool for both genders used to:
Optimize fueling around sessions
Avoid overtraining and plateau
Preserve long-term health and consistency
As more athletes push toward “marginal gains,” understanding and monitoring EA has become a cornerstone of world class endurance coaching.
The Model :
Energy Intake (kcal) - Exercise Energy Expenditure (kcal) / Fat Free Mass (FFM) in kg
This gives us a number and we should aim for a figure of 45 kcal/kgFFM/day and have a lower limit of 30.
The Thresholds:
45 kcal/kg FFM/day = optimal
30 kcal/kg FFM/day = low EA threshold — below this, physiological dysfunction is likely
<30 kcal/kg FFM/day = clinical concern (linked to RED-S)
Some Examples :
Checking Current Intake
Athlete X : 72 kg, 15% body fat → FFM = 61.2 kg
EEE: 75 min trainer ride (800 kcal) + 40 min run (600 kcal) = 1,400 kcal
Daily intake: 3,800 kcal
EA = (3,800 – 1,400) / 61.2 = 39.2 kcal/kg FFM/day
That’s sub-optimal, but still above the clinical floor. This athlete may benefit from a small intake increase on heavy days.
Planning Energy Intake :
Big Training Day Example
Long ride: 2,000 kcal
Run off the bike: 400 kcal
EEE = 2,400 kcal
EA Goal = 45 x 61.2 = 2,754 kcal
Required intake = 2,754 + 2,400 = 5,154 kcal
Easy Training Day Example
Swim : 400 kcal
EA Goal: 45 x 61.2 = 2,754 kcal
Required intake = 2,754 + 400 = 3,154 kcal
NOTE !! Energy intake includes all food eaten that day and in-training nutrition.
Summary :
The Energy Availability (EA) model is a modern, evidence-based approach to fueling that helps endurance athletes balance training demands with overall health. By calculating EA as the difference between energy intake and exercise expenditure, divided by fat-free mass, athletes and coaches can ensure there's enough energy left for vital functions like hormone regulation, bone health, and recovery.