Relative Energy Deficiency in Sport RED-S


-German Journal Sports Medicine

In simple words: 

The energy input (calories) of an athlete doesn’t match the energy output (exercise).

There are two types of RED-S Voluntary and Involuntary

Some athletes develop RED-S because they actively restrict their food intake or increase their activity level. 

Others just don’t know how much food their body actually needs to fuel the exercise they do. 

Both leads to RED-S. 


The Reasons:

As athletes, we often strive for perfection. We try everything to maximize our performance. Especially in “lean sports”, such as running, cycling, or climbing, perfectionism means cutting down on weight. The only way to get there is by eating less, which – when done in excess – sometimes comes at a price: RED-S.

Sometimes an athlete’s environment of coaches, parents, peers, and social media suggests that losing weight could be the key to higher performance. This creates pressure and in some cases eating disorders. 

The narrative of “smaller to be faster” is deeply entrenched in our minds.

That’s why we should work together to create a new narrative of “fuel to be faster and stronger”. 

A Norwegian study examined the prevalence of eating disorders in elite athletes.

The participants had to fill out a questionnaire and went through a clinical interview.

The results were then compared to a control group of non-athletes. 

The Results:

Male Athletes
Female Athletes

Being an athlete puts you at a greater risk of developing disordered eating. 

That’s why it’s important to keep checking in with yourself and making sure you don’t have any of the following symptoms. 

Warning Signs:

Chronic fatigue, Stress fractures, Osteoporosis, Depression, High risk of injury, Decreased muscle strength, Amenorrhea, Endocrine disorders, Weak immune system, Nutritional deficiencies, Stomach issues

These symptoms are caused by the imbalance of energy expenditure and energy intake, which slows down the metabolism.

This has several consequences: 

Diagnosing RED-S isn’t always straight forward.

Symptoms are often believed to have a reason other than being energy deficient. 

So how can you spot RED-S in others?

Now to the most important question:

How can you recover from RED-S? 

It sounds easy. But it isn’t. 

Recovering from RED-S takes time, patience, and grit. 

So here’s how to recover from RED-S

RED-S recovery consists of essentially three steps. What looks easy at first glance can be harder than it seems. Recovering from RED-S comes with a lot of (mental) hurdles in your way.

Whether RED-S is intentional or unintentional for you, find a recovery path that works for you. We all recover from RED-S differently! That’s why it’s important not to compare yourself with other athletes – no matter at which stage they are. 

If you don’t know where to start or if you’re stuck, it’s always a good idea to get additional help from a sports nutritionist or therapist. 

Eat More.

Eating more can sound intimidating at first. But in the end, an extra amount of food will give you just an extra amount of energy. If you don't really know where and how to start, try to add 100 or 200 calories to your daily diet. 

Don't worry about the weight gain. You fuel to get stronger and faster as you work with your body instead against it. 

Step 1

Step 2

Exercise Less.

Coming from the constant urge of wanting to become faster, it is easy to forget that we actually get faster by giving our bodies time to recover from training. 

While you are recovering from RED-S, cutting down on both exercise volume and intensity is key. 


This might be the hardest part. As an athlete, you are probably used to the never-ending cycle of self-optimization. But in RED-S recovery, you are supposed to take a step back and relax. 

Step 3

What does science say on preventing and recovering from RED-S?

Post-Workout Fuel The most important rule

Not eating directly after practice is the same as not eating enough calories. The 30-minute time frame after a workout are extremley important to signal your body that it is not threatened by famine. Of course, you’re not really starving, but your body is smart and slows down the metabolism to increase fat storage. 

Grams of protein

Especially as a woman, you should have a snack about 30 to 45 minutes after exercise because that’s when your body can absorb glucose best. Men tend to have a larger recovery window of up to 3 hours. 

Your post-workout snack should contain at least 25 grams of protein, ideally with 5 to 7 grams of BCAAs. Make sure to bring a protein bar or protein shake. Find out more in the book ROAR or the author’s website

After RED-S:

How can you prevent relapse while maintaining a healthy race weight?

Preventing Relapse

Remember that food is energy. And energy makes you run faster or ride further or lift stronger.

Fuel properly

The key is to fuel at the right time. Make sure to have at least a snack before and after a training session. Don't forget to bring a snack or two on long runs and rides!

Maintaining a healthy race weight

Seeing a performance nutritionist can help you figure out how much food and what kind of food you need. Remember that just like your training demands change from season to season, your energy demands do, too.