Relative Energy Deficiency in Sport happens when an athlete takes in too little energy for their training, for long enough or by enough to harm health and performance. A tool in every edition explains the warning signs and can take you through a recognised screen, one question at a time.
In shortRelative Energy Deficiency in Sport (RED-S, now often written REDs) is the set of health and performance problems caused by low energy availability that lasts a long time or is severe: too little energy left after training for the body to work normally. Every Athleet.Ai edition has a tool where you can ask about the warning signs or work through the Low Energy Availability in Females Questionnaire (LEAF-Q) as a conversation, one question at a time, scored with its authors' published key. In most sports it is a coach tool; in Track and Field, coaches, athletes and parents each have it, and in Golf it is in the golfers' tools. The result shows the total, the injury, gut and menstrual sections, any red flags and who to see next. It is a screen, not a diagnosis: only a doctor can diagnose RED-S.
Never the whole questionnaire at once. Earlier answers skip questions that no longer apply, so most screens take 10 to 16 questions, and every question accepts 'don't know' or 'skip'.
Injuries in the last year, including bone stress injuries; gut function; and contraception and periods.
A total of 8 or more means at risk and worth assessing further. Each section has its own flag, set by the questionnaire's authors: injuries 2, gut 2, periods 4.
No first period at 15 or older; no period for three months or more now, when not pregnant or using hormonal contraception; any bone stress injury, especially at the hip (neck of the thigh bone), sacrum or pelvis; unintended weight loss, dizziness or fainting; or signs of disordered eating.
The LEAF-Q was developed and validated with adult women. For a male athlete the tools hold a shorter, unscored conversation about the same signs, including low sex drive, and give the same next steps.
The questionnaire was validated with women aged 18 to 39 answering for themselves, so for younger athletes, or when a coach or parent answers, the score is only a rough guide. For under 18s a parent or carer and a doctor are involved if there is any concern.
Open the RED-S tool for your sport (in Padel, Basketball and American Football it is the coaches' nutrition tool) and say what is worrying you, or ask to run the screen.
One short question at a time, each with plain answer options. No full name or date of birth is needed.
The score, the three sections, any red flags, and what unknown answers or hormonal contraception mean for how far the result can be trusted.
Who to see, usually a GP or sport and exercise medicine doctor, ideally with a registered dietitian who specialises in sport, what to take with you, and when to repeat the screen.
For coaches, the screen is in the REDs tool in Track and Field, Football, Triathlon and Skating, and in the coaches' nutrition tool in Padel, Basketball and American Football, part of the Coach, Small Club and Club plans. Track and Field athletes and parents have it in their own REDs tools, in the Athlete, Parent and Family plans, and in Golf it is in the golfers' tools, in the Athlete and Family plans. There is no extra cost.
Relative Energy Deficiency in Sport is the term the International Olympic Committee uses, written REDs in its 2023 consensus statement, for the harm done by low energy availability that lasts a long time or is severe. It can affect metabolism, periods and hormones, bone and muscle health, immunity, heart and blood health, the gut, mood, recovery, injury risk and performance, in male and female athletes at any level. It can happen without any weight loss.
Missed or irregular periods, low sex drive in men, repeated injuries and especially bone stress injuries, frequent illness, persistent tiredness, gut problems, low mood and falling performance. Some signs need a doctor on their own: no period for three months (when not pregnant or using hormonal contraception), no first period by 15, a bone stress injury, or fainting. Fainting during or after exercise always needs urgent medical review.
The Low Energy Availability in Females Questionnaire, a 25 item screen developed by Melin and colleagues in 2014 with female endurance athletes and dancers aged 18 to 39, and validated in endurance athletes. A score of 8 or more means at risk of low energy availability and worth assessing further.
No. It is a screen. Only a doctor with expertise in RED-S can diagnose it, usually working with a dietitian and other specialists, using the IOC REDs Clinical Assessment Tool, version 2, alongside other tests. The tools say so in every result and never diagnose RED-S, an eating disorder or any other condition.
Less well. A 2023 study of 60 professional female footballers, by Dasa and colleagues, found the LEAF-Q did not reliably identify low energy availability or its effects, and the researchers concluded it should not be relied on in female footballers. Results in football and other team sports, where the evidence is limited, are read with extra caution. The LEAF-Q was also not validated in athletes using hormonal contraception, which can mask a missing natural cycle, so the period section may under-read.
In the Track and Field Edition, yes: the parent REDs tool asks the questions about your child in age-appropriate language and explains why periods matter. The score is only a rough guide for under 18s, and if anything suggests a concern, the advice is to involve a doctor promptly. In Golf it is in the golfers' tools, and in the other sports it is in the coach's tools.
No. The screen uses neutral language about food and bodies and never suggests weight loss, and Athlete Fuelling never sets a calorie deficit.