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Nutrition for Optimal Recovery

By Gaelle Abecassis | Dec 4, 2022

Preventing Relative Energy Deficiency

As you embark on an intensive training season, be on the lookout for signs of overtraining or Relative Energy Deficiency in Sport (RED-S). Symptoms may include fatigue, loss of performance, mood disturbance, illness, or injury, and they can be damaging to your exercise performance and your health. But as you train, it’s important to remember that RED-S can be difficult to avoid because you may start experiencing it before you notice any symptoms.  

Like most endurance athletes, you probably have a well-thought-out training plan with rest periods between sessions and recovery days that should prepare you to be at your best on race day. However, even the most detailed training plans can’t account for the fact that you are a unique individual with your own range of motion, psychological state, illnesses, nutrition, hormones, genetics, and nervous system activation. All of these factors influence how you respond to training. A heavy training schedule can create excess stress on your body, which can be exacerbated by other stressors, such as work pressures, family commitments, or lack of sleep. If you combine these stressors with a sub-optimal diet that fails to cover your energy needs or provide enough nutrients to support an increased energy demand, you may be at risk of overtraining or relative energy deficiency. 

This article will discuss Relative Energy Deficiency in Sport (RED-S), how to identify its symptoms and help you understand the potential health consequences. We will also explore how proper nutrition can help you mitigate the risks, recover well, and stay healthy during your training season.

Relative Energy Deficiency in Sport (RED-S)

1. What is Relative Energy Deficiency in Sport (RED-S)?

RED-S is the imbalance between your food intake (energy and nutrient availability) and what your body requires to support your exercise and life-sustaining activities. It can be due to excessive exercise, inadequate nutritional intake, or insufficient recovery. 

When the energy availability is too low, the body enters into an “energy-saving mode” in which hormone production and metabolic processes are impaired, affecting all systems throughout the body (reproduction, growth, cardiovascular, immune, skeletal, and muscular). 

Over time, this imbalance can adversely affect all aspects of sports performance (see Figure 3 - RED-S Potential Health Consequences and Performance Effects). An athlete continuously training with low energy availability may experience poor performance, mood disturbances (anxiety, depression), poor cardiovascular health, increased injury risk, poor immune health, and hormonal and metabolic disruptions. Impaired bone health is another significant implication of RED-S: hormonal disruptions impact bone mineral density, increasing fracture risk. I may also prevent young athletes from reaching peak bone mass and cause irreversible bone loss in senior athletes.¹

Figure 3 - RED-S Potential Health Consequences and Performance Effects

2. RED-S or Overtraining?

You may be more familiar with terms like “overtraining” or “training overload,” which describe athletes who have “burned out” due to excessive training load and insufficient recovery. Overtrained athletes typically experience health decline, fatigue, performance drops or plateaus, mood disturbances, and increased injury and illness. 

You may notice similarities with the symptoms for RED-S. This is because the underlying issue is the same: affected individuals have metabolic and physiological imbalances that interfere with normal health functions and limit their performance. In many cases, overtrained athletes are misdiagnosed, and the symptoms they experience are due to under-fueling.² In many cases, it’s simply a matter of terminology where sports dietitians refer to RED-S and sports scientists refer to overtraining. In both cases, achieving optimal nutritional intake can help alleviate those disturbances. 

3. Assessing RED-S symptoms: Are you at risk?

While energy deficiency can be created intentionally (e.g., deliberately restricting calorie intake to lose body fat), it’s often unintentional — especially during heavy training periods where it can consume all the calories your body needs to function, let alone exercise. You may not see any symptoms at first, but they will appear if you continue under-eating relative to your training for several months. 

As your body tries to compensate for the excess loads, your sympathetic nervous system activity will increase. The first signs you may notice are a reduction in heart rate variability or an increase in resting heart rate. You may also produce more cortisol (the stress hormone) and notice that you need more carbohydrates during exercise. Of course, you may just notice that you feel more fatigued after your workout. For women of childbearing age, loss of menstrual periods is a typical sign of RED-S. Struggling to improve sports performance or persistent fatigue are also good indicators. 

Other signs of RED-S include:

•Irritability

•Anxiety or Depression

•Weakened Immunity

•Muscle Aches 

•Higher Susceptibility to Injury 

•Disrupted Sleep

•Altered Appetite¹ 

If you notice any of these signs, you should re-evaluate your training load, your periodized nutrition, and your recovery. Don’t wait for your performance to drop or for an injury to happen before you take action! 

Optimize Your Nutrition for Best Recovery

1. Check your energy balance. 

Start your nutrition evaluation by looking at your approximate energy intake compared to your energy expenditure. According to the International Society of Sports Nutrition (ISSN),³ a regular diet is between 1800–2400 kcals/day (or 25–35 kcals/kg/day for a 50–80 kg individual), but you may expend 600–1200 kcals or more for each hour of exercise based on the intensity. So depending on your training load, you may reach a total caloric expenditure of 2000–7000 kcals/day (or 40–70 kcals/kg/day for a 50–100 kg athlete).

For optimal health and performance, we recommend staying in energy balance for most of the training season, limiting caloric deficits to 250-500 kcal/day, and saving fat loss for the off-season. You should assess your food intake versus your energy expenditure for a short period.⁴ A simple approach could be to use an app like My Fitness Pal to track your weekly food intake and estimate your energy expenditure using a device such as a sports watch, smartwatch, or Fitbit. If you observe significant energy deficits, you should address them by increasing your food intake, reducing your training load, or a combination of both.¹

2. Tailor your carb quantity and timing to your training.

You should always consume enough carbohydrates to meet the requirements of your training program. To accomplish this, we recommend ingesting 6-10 g of carbs per kg of body weight per day during training phases that require one to three hours of moderate to high-intensity exercise per day. Carbohydrate consumption at this level will restore your pre-exercise glycogen stores for the next day.^5,6,7

You should also try to schedule your carb intake around your training sessions to ensure high-carb availability for high-intensity or long-duration training. You can do this by consuming carbs before and during those sessions: 1-4 g of carbs per kg of body weight 1-4 hours before the session, and 30 to 60 g/hour of carbs for workouts lasting more than one hour. You also want to optimize the replenishment of muscle glycogen stores between workouts, especially if you train daily or twice a day. Carbohydrate intake in the first hours following exercise is essential to maximize glycogen resynthesis. If your recovery time is less than four hours, you should implement a speedy refueling with 1.2 g of carbs kg per hour for the first few hours post-exercise. The highest glycogen synthesis rates are obtained when ingesting carbs at 15-30 minute intervals in the first 3-5 hours of your recovery period.^5,6,7This is an excellent time to include high glycemic foods, including sport nutrition products such as bars, gels, or drinks.

3. Optimize your recovery nutrition

In addition to the recommended carb intake, the following foods can help your recovery.

Protein

Protein is beneficial for proper recovery as it boosts glycogen repletion and stimulates muscle protein synthesis. 

•You can boost glycogen repletion by reducing your carb intake to 0.8 g/kg/h and combining it with 0.2–0.4 g/kg/h of protein.

•Post-exercise protein with a high leucine content (700–1300 mg) within the first two hours can stimulate muscle protein synthesis and recovery. Maximal stimulation of muscle protein synthesis can be reached with a protein intake of approximately 0.25–0.30 g per kg of body weight per meal.⁵

•Consume frequent meals during your recovery period to ensure optimal muscle glycogen repletion and protein synthesis due to high plasma glucose, insulin, and amino acid availability.⁶ 

Caffeine 

If you cannot tolerate high carb doses, consider adding caffeine (3 mg/kg, up to 8 mg/kg), as it will boost glycogen repletion by up to 66%.⁵Caution is required, though, as caffeine can be toxic when consumed in high doses. 

Antioxidants

Intense exercise will increase oxygen consumption in your muscles, raising free radical and reactive oxygen species (ROS) levels. An excess in oxidant load will delay recovery. To counter this effect, consume high-antioxidant foods (such as cherry juice, berries, pecans, broccoli, or dark chocolate) to improve recovery.⁵

Omega-3

Omega-3 from fatty fish (e.g., salmon, sardines, mackerel), seafood, grass-fed beef, or nuts have anti-inflammatory effects that have proven beneficial against inflammation and oxidative stress caused by intense exercise.

Creatine

Studies have shown that supplementing with creatine can enhance recovery from intense exercise by increasing glycogen storage and muscle protein synthesis. Creatine is also known for its ergogenic effect in endurance sports.^7,8

4. Consume nutrient-dense foods and watch for potential deficiencies.

Opt for good quality, nutrient-dense foods, such as vegetables, fruits, legumes, whole grains, nuts, seeds, fish, meat, eggs, or dairy products, to obtain the vitamins and minerals needed to support your activity levels.

Your exercise increases your oxidant load, and you should therefore choose minimally processed foods and avoid foods that may increase oxidative stress. A diet rich in fruits and vegetables is particularly beneficial as they are high in antioxidants such as vitamins C and E.⁹

Eating a variety of foods from each food group is an excellent way to ensure you consume all the essential nutrients. Generally speaking, you should not exclude whole food groups unless you have a medical condition. 

As an endurance athlete, you’ll also want to be careful to avoid common deficiencies, including iron, vitamin D, calcium, and some antioxidants such as vitamins E and C.⁹

Iron

Iron is essential for oxygen transport throughout the body, and, according to experts, athletes have more significant iron requirements than the general population, with female athletes requiring up to 70% more. As a result, iron deficiency is common in endurance athletes, especially females. Causes for iron deficiency are various, including heavy menstruation, inadequate dietary intake, gastrointestinal losses, and intravascular or sweat-related training losses. If you’re unsure whether you have an iron deficiency, you may want to get tested. If you are deficient, increase your intake of iron-rich foods (e.g., liver, legumes, red meat, shellfish, seeds, dark chocolate, spinach, amaranth) or supplements (under the supervision of a health or nutritional professional).⁹

Vitamin D

Vitamin D helps regulate many metabolic pathways, improves bone health, reduces inflammation, and supports optimal muscle function. Low Vitamin D in athletes (<30 ng/mL) has been associated with increased bone stress injury and heightened inflammatory responses post-exercise. Maintaining proper levels reduces these risks considerably. If you are prone to stress fractures or feel muscle pain or weakness, get tested regularly and be careful to notice signs of RED-S.

Pro tip: We get our vitamin D from sun exposure, but our lifestyle may limit this exposure — especially during the winter. If you’re deficient, you may want to increase your sun exposure.^1,9

Calcium

Like Vitamin D, calcium is critical for bone health. It is also vital for muscle contraction, nerve conduction, and clotting functions. Calcium deficiency increases the incidence of bone stress injury and contributes to low bone mineral density and low energy availability. It is recommended to consume 1500 mg per day of calcium along with 1500 to 2000 IU of Vitamin D for optimal bone health.^1,9If you suspect deficiencies, always consult a health or nutritional expert before taking any supplement.

Conclusion

Maintaining energy availability, adjusting the quantity and timing of your nutritional intake based on your training sessions, and eating a nutritious whole-food diet can help mitigate the risks of RED-S or overtraining. 

If you are concerned about any of those aspects, please contact us. We will be happy to create a tailored nutrition plan to help you stay healthy, stay on track with your training, and be at your best every day so you can confidently approach your race day. And if you want to learn more about the ideal race-day nutrition, be sure to read our next article!​​

References

1. Mountjoy M, Sundgot-Borgen J, Burke L, et al. International Olympic Committee (IOC) consensus statement on relative energy deficiency in sport (RED-S): 2018 update. Int J Sport Nutr Exerc Metab. 2018;28(4):316-331.
2. Stellingwerff T, Heikura IA, Meeusen R, et al. Overtraining Syndrome (OTS) and Relative Energy Deficiency in Sport (RED-S): Shared pathways, symptoms and complexities. Sports Med. Published online 2021.
3. Kerksick CM, Wilborn CD, Roberts MD, et al. ISSN exercise & sports nutrition review update: research & recommendations. Journal of the International Society of Sports Nutrition. 2018;15(1). 
4. Casazza GA, Tovar AP, Richardson CE, Cortez AN, Davis BA. Energy availability, macronutrient intake, and nutritional supplementation for improving exercise performance in endurance athletes. Curr Sports Med Rep. 2018;17(6):215-223.
5. Vitale K, Getzin A. Nutrition and Supplement Update for the Endurance Athlete: Review and Recommendations. Nutrients. 2019;11(6):1289. Published 2019 Jun 7. doi:10.3390/nu11061289
6. Fritzen AM, Lundsgaard A-M, Kiens B. Dietary Fuels in Athletic Performance. Annual Review of Nutrition. 2019;39(1):45-73.
7. Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine joint position statement. Nutrition and athletic performance. Med Sci Sports Exerc. 2016;48(3):543-568.
8. Wax B, Kerksick CM, Jagim AR, Mayo JJ, Lyons BC, Kreider RB. Creatine for Exercise and Sports Performance, with Recovery Considerations for Healthy Populations. Nutrients. 2021; 13(6):1915.
9. Bytomski JR. Fueling for Performance. Sports Health. 2018;10(1):47-53.