It used to be called the female athlete triad: a condition characterized by missed menstrual periods, a drop in bone density, and stress fractures resulting from eating too few calories. For years, the condition was considered a concern only for women–and only those who have lost their period. Women who retained their periods were not considered to be at risk, and men, whose hormone systems were different, were thought not to be affected.
In 2014, after an extensive review of the medical literature, the International Olympic Committee officially renamed the RED-S condition (relative energy deficit in sport) and expanded the definition to recognize that the basic problem is consuming too few calories to supporting your whole body has to do, a problem that is broader than the traditional female triad and can affect both men and women.
When not actively training, the body’s energy balance is severely skewed towards things other than exercise. The brain needs about 20 percent of the average person’s overall calorie intake. The liver needs about the same amount. Lesser amounts go to the heart, kidneys, and other organs needed to keep you alive and functioning. For non-athletes, muscles are relatively minor contenders in this competition, requiring only 20 percent of the total energy intake.
For athletes, of course, the muscle demands are much higher. But as long as you eat enough, everything stays in balance. The problem comes with trying to lose weight or just trying to maintain lean body mass. When that happens, says Lewis Halsey, an environmental physiologist at the University of Roehampton in London, you encounter a mysterious aspect of human physiology known as energy compensation. “Put simply,” he says, “our bodies partially compensate by cutting the energy spent on other things.”
We are designed to survive; in the face of what is perceived as hunger, our bodies will find ways to compensate for it. This compensation, says Halsey, includes “arrest in a desperate attempt to limit your negativity.” This is RED-S in a nutshell.
The focus was initially on women because women had a clear sign of menstruation, says Nicky Keay, an exercise endocrinologist at University College London and Durham University. “We now have strong evidence that men should pay attention.”
In one study, for example, Keay looked at 50 competitive male cyclists: four internationally, 20 nationally, and the rest regionally. She then provided them with a questionnaire and a clinical study visit, aimed at identifying those whose eating habits were restrictive enough to place them in a category that she described as “low energy availability”. This rating was specific to cycling, but the basic questions were those that other athletes may also refer to, such as average weekly training volume (including cross training), how often they trained fasted, history of intentional weight loss, how they fed for workouts that lasted more than an hour, what they ate next, and other training and diet questions.
The results were astounding. Those whose training and dietary patterns seemed insufficient had substantially lower bone density and testosterone than would be expected for men their age. There was also an effect on athletic performance. “Those athletes judged to be low on energy didn’t do the same,” says Keay. In the 60-minute time trials comparing average power, calculated in watts per kilogram, which would theoretically give lighter riders an advantage, athletes showing signs of RED-S scored worse.
Kathy Butler, the coach of the Run Boulder Athletic Club and head of U.S. track and field training education, says RED-S can harm health in many other wide-ranging ways besides reduced bone mineral density, including negative effects on the immune system, heart, mood, coordination, glycogen supply and thyroid level. Athletes should also note that protein synthesis requires energy. If this is in short supply, the body may not only be unable to rebuild stronger after a workout, but it may also find it difficult to recover. One of the possible effects of RED-S, Butler says, is a reduction in muscle strength.
These results aren’t limited to top competitors, says Keay. “Many people have the perception that only elite athletes get this,” he says. “But I’d say it’s more like non-elite wannabe amateurs.” The elites are touchy but often surrounded by teams of doctors, coaches, nutritionists, and other experts who can spot impending problems. “While if you’re a well-meaning amateur, you don’t have the backup, so it’s easy to misjudge things,” says Keay.
In male athletes, recognizing the signs of RED-S can be much more difficult than it is for women. It is usually diagnosed via a battery of blood tests, but there are also symptoms that athletes can recognize for themselves. Fatigue not explained by something obvious, such as lack of sleep or increased stress, is an important indicator, Butler says, as is repeated injury or illness. Keay adds a low libido to the list, or just a general lack of energy and enthusiasm. Poor sleep and digestive problems can also be signs of RED-S.
While a restricted diet is the cause of RED-S, it’s not necessarily linked to being too thin, says Keay. People with RED-S may not look underweight and may not have any problems.
The solution, he says, is to trust that millions of years of evolution have programmed your body to function at its best if you give it what it needs. If you artificially limit it in an attempt to reach a hypothetical ideal running weight, “the body will get scared,” says Keay. It will go into power saving mode and both your overall health and performance will suffer.
Butler says the solution may be as simple as the often claimed advice to consume around 300 calories of food or drink as soon as possible after training. Studies have indicated that waiting too long between meals or snacks can put your body into an intermittent hunger mode it wouldn’t otherwise encounter. Simply changing the time you eat to make sure you get what you need when you need it may be all it takes to throw it out of that mode and into a healthy state.
It’s important not to let this post-workout fuel replace your regular meal intake. If you do, your total calories may still be too low. And, Butler points out, failing to refuel as little as 300 calories a day is equivalent to losing an entire month of food over the course of a year.
If all of this seems somewhat vague and complex, it is. Nutritional problems are rarely straightforward. What’s simple is the bottom line: Men run the risk of having energy deficiency problems just as much as women, even if the symptoms aren’t as obvious. If your health, performance, mood or general energy is on the decline and you are heavily focused on weight or diet, the answer may be that you are excessively limited in calories and need to relax. Change your eating patterns to snack immediately after workouts or add an energy bar or two to your regular diet. And if you’re not sure how best to do this, consult a nutritionist.