Fueling for the Long Haul: Are You at Risk for REDs?
For cyclists, the equation often seems simple: lighter equals faster. Leading to a relentless pursuit of a higher power-to-weight ratio. Meticulous tracking of calories and push training to the limit. But what happens when this quest tips the bodys delicate balance too far? The answer could be something termed Relative Energy Deficiency in Sport, or REDs, a syndrome that can silently sabotage both your health and your performance.
What is REDs?
Relative Energy Deficiency in Sport (REDs) is a condition caused by "low energy availability" (LEA). This happens when your energy intake from food is not enough to cover the demands of your training and support your body's essential functions.
Think of your body's energy as a budget. Training is a major expense, but so are functions like metabolism, bone health, hormone regulation, and immune function. When you're not fueling enough, your body starts to cut funding to these "non-essential" projects to save energy, leading to a cascade of negative health and performance consequences.
This energy deficit can be intentional, through strict dieting, or unintentional, simply by not realizing how many calories a high-volume training block truly requires.
It's not just about weight loss
A common misconception is that an athlete with REDs must be losing weight. However, it is entirely possible to be weight-stable—or even gain a small amount of weight—while in a state of REDs.
This happens because the body is incredibly adaptive. When faced with a chronic energy deficit, it can suppress its own resting metabolic rate (RMR) to conserve energy. Because of this metabolic adaptation, your total daily energy expenditure decreases. An energy intake that was previously too low might now be enough to maintain your weight at this new, suppressed metabolic state. The problem is, this intake is still not enough to properly fund essential functions like hormone production and bone maintenance. This is why weight is not a reliable indicator; an athlete can appear healthy on the scales while their internal systems are struggling.
How REDs affects cyclists
While REDs can affect any athlete, cyclists are actually particularly vulnerable. Cycling is a sport that often emphasizes a lean physique and involves high overall training volume plus long duration high-energy expenditure training, which are major risk factors. Here's how it can manifest:
Performance hits a wall (or goes backward)
Contrary to the "lighter is faster" belief, chronic under-fueling can seriously impair performance. While short-term, supervised phases of energy deficit might offer a temporary edge by improving the power-to-mass ratio, prolonged LEA almost always leads to negative outcomes.
Strength and explosive power: Studies show that LEA can reduce explosive power. One randomized trial in male endurance athletes found that countermovement jump (CMJ) performance declined as energy availability was progressively reduced.
Endurance: While some studies show mixed results, LEA can negatively affect endurance capacity. Reduced muscle glycogen stores, hormonal disruptions, and impaired recovery all contribute premature fatigue across the board in endurance performance. This is almost always true in absolute terms and often relative to weight as well.
Training adaptation: When your body is in a state of energy conservation, its ability to adapt and respond to training stimuli is compromised. You might be putting in the work, but not achieving the results you deserve.
Hormonal disruption
One of the first systems to be down-regulated during LEA is the reproductive system.
For MALE cyclists: This can lead to what's known as "Exercise-Hypogonadal Male Condition," characterized by suppressed testosterone levels. Studies have shown that male cyclists with low energy availability also had lower testosterone levels. The consequences include low libido, fatigue, and impaired recovery. A common warning sign is not having a morning erection, which is normal in a healthy male.
For FEMALE cyclists: LEA is a primary cause of menstrual dysfunction, including irregular periods or the complete absence of menstruation (amenorrhea). This is not a sign of peak fitness; it's a major red flag for REDs.
Compromised bone health
In addition, cycling is a low-impact sport, which means it doesn't provide the bone-building stimulus that weight-bearing activities do. This already puts cyclists at a higher risk for low bone mineral density (BMD). Add LEA into the mix, and the risk escalates significantly.
Hormones like estrogen and testosterone also play a vital role in bone maintenance. When their production is suppressed due to REDs, bone breakdown can outpace bone formation, leading to osteopenia or osteoporosis and an increased risk of stress fractures. Even if you don't suffer a fracture, low BMD is a serious long-term health concern.
Best practice guidelines to avoid REDs
Preventing REDs isn't about abandoning performance goals; it's about pursuing them sustainably. The key is a health-first approach grounded in smart, evidence-based practices. Here are some guidelines every cyclist should follow, that we’ve based on recommendations from an expert IOC consensus group:
1. Acknowledge and educate
First, understand that achieving an "ideal" body composition is not a guarantee of success and should not come at the expense of health. An effective way to do this is educating yourself on the signs of REDs, including fatigue, decreased performance, hormonal changes (like menstrual irregularities or low libido), recurrent illness, and mood disturbances.
2. Take a multidisciplinary approach
Monitoring and manipulating body composition should ideally be managed by a multidisciplinary health and performance team, including a qualified sports dietitian/nutritionist, a physician, and if needed, a psychologist. Doing it entirely yourself is not a great idea and only consulting your coach or experienced teammate is not enough.
3. Justify and consent to assessments
No one is debating where body composition can affect performance, but regular body composition assessments should not be routine for everyone, and there must always be a clear, evidence-based rationale for why a change in body composition is needed for a specific athlete. But remember that frequent assessments can increase anxiety and promote an unhealthy focus on weight. Follow-up measurements should not exceed 4-6 times per year. Also, assessments should be voluntary and an athlete must provide informed consent and should have the right to opt out at any time without penalty. Any type of body composition assessments should be completely avoided for athletes under 18, unless medically indicated for monitoring growth and development. The focus for young athletes should be on skill development and fueling for adaptations.
4. Handle data with confidentiality and care
Acknowledge that body composition data is private confidential medical information. The results should only be shared with the athletes consent, and with as few others as possible, most often a sports dietitian or physician. The data should be interpreted individually, focusing on longitudinal changes for that athlete rather than comparing them to team averages or arbitrary "ideal" numbers. Any report should include measures of both fat mass and lean mass.
6. Prioritize fueling
If a change in body composition is justified, the first step should always be to fine tuning your current fueling strategy with the guidance of a sports dietitian. The goal is to optimize energy status, not just cut calories. Nutrient timing is crucial. Focus on adequate fueling before, during, and after your rides to support performance and recovery.
Key fueling strategies to avoid REDs
1. Boost overall energy intake
Prioritize calories: The main goal is to increase your total energy intake to meet the demands of both your training and your body's basic functions.
Increase gradually: Add 300-500 kcal per day by incorporating extra snacks or making current meals more energy-dense. A sudden large increase can be hard to sustain.
Nutrient quality: Ensure your increased intake also covers your needs for essential macronutrients and micronutrients, particularly calcium and vitamin D for bone health.
2. Match intake to training load
Adapt intake to energy output daily: The preferred strategy is always to increase energy intake to match your exercise expenditure. Eating the same amount of energy each day, regardless of how much you’re expending leads to the negative effects of REDs on your high load training days. On top of that, you also risk overeating on rest days or easy training days, which can possibly lead to weight gain.
Adjust training (if needed): However, increasing intake can be more challenging that expected for some athletes for various reasons, like feeling full or not enjoying common energy dense foods. If increasing food intake sufficiently isn't feasible or isn't resolving LEA symptoms, a temporary, planned reduction in training volume or intensity might be necessary to lower energy expenditure. A good coach knows how to design a training plan with a lower total energy expenditure, that still provides an effective training stimuli, so you don’t risk loosing fitness in the process.
3. Prioritize Carbohydrates
Don't skip carbs: Endurance athletes like cyclists need ample carbohydrates and are often at risk of under-consuming them. Sure, cyclist normally have a decent intake during rides, but the long duration of many training sessions limit the time available to eat enough during the 24 hours we each have.
Performance & health: Sufficient carbohydrate intake is vital not only for fueling training itself but also for fueling the adaptations from training, like regulating anabolic hormones and tissue growth or rebuild.
4. Optimize Daily Meal Timing
Avoid within-day deficits: Spread your energy intake consistently throughout the day. Long gaps without eating can lead to metabolic suppression, so even if your total daily calorie goal is met you might still be experiencing some of the negative effects of REDs.
Fuel around training: Pay special attention to fueling before your rides, sufficient intake during the session (which can vary depending on the type of training) and consume a recovery snack or meal with carbohydrates and protein afterwards. Avoid skipping meals near workout times.
By adopting these health-focused guidelines, cyclists can continue to strive for peak performance without sacrificing their long-term well-being. Remember, a well-fueled engine is a powerful engine. Ride strong, ride healthy.
