Sports nutrition is often reduced to a list of miracle foods or a fixed macronutrient ratio. Recent scientific recommendations shift the focus: what determines daily performance is less about the exact contents of the plate and more about the balance between energy intake and energy expenditure during training.
The concept of energy availability, formalized by the International Olympic Committee in its 2023 consensus statement on REDs (Relative Energy Deficiency in Sport), redefines how nutrition should be approached for any regular practitioner.
Energy Availability and REDs: The True Indicator of Sports Nutrition
Most content on sports nutrition focuses on grams of protein or percentage of carbohydrates. The problem is that a “correct” intake of macronutrients can mask an overall energy deficit. This is what the IOC consensus on REDs highlights.
An athlete who increases their training volume without adjusting their caloric intake enters a zone of energy availability deficit. The consequences affect performance, but also sleep, immunity, bone density, mood, and hormonal regulation, in both men and women.
The signals to watch for are not dramatic: persistent abnormal fatigue, sleep disturbances, recurring injuries, decreased libido, or menstrual irregularities. Just one of these signs, combined with an increased training load, warrants a reevaluation of daily food intake. The articles compiled in the nutrition section of Va Y Avoir Du Sport allow for a deeper understanding of the links between diet and effort.
The approach recommended by sports nutrition practitioners since 2024 emphasizes systematic adjustment of intake to training volume rather than applying a standardized diet. A rest day does not require the same intake as a day with two training sessions.
Meal Timing Around Training: Comparison of Nutritional Windows
The total daily caloric intake matters, but its distribution around exercise significantly changes the quality of the session and recovery. Recent recommendations emphasize the placement of energy, not just its quantity.
| Window | Main Goal | Recommended Type of Intake |
|---|---|---|
| 2 to 3 hours before the session | Replenish glycogen stores | Meal rich in complex carbohydrates, moderate in protein, low in fats |
| 30 minutes before the session | Maintain blood sugar levels | Light carbohydrate snack (fruit, applesauce, bar) |
| During exercise (beyond 1 hour) | Provide immediate fuel | Simple carbohydrates, hydration with electrolytes |
| Within 30 minutes after the session | Initiate muscle recovery | Carbohydrates + proteins (favorable ratio for glycogen resynthesis) |
| Following meal (1 to 2 hours after) | Complete recovery | Balanced complete meal with vegetables, starches, proteins |
The post-exercise window is often overestimated for recreational athletes who train once a day. The meal following the session matters more than the immediate snack when the next session is more than 24 hours away.
In contrast, for practitioners who have two sessions in the same day, the post-exercise snack becomes crucial. Ignoring this window leads to incomplete recovery of muscle glycogen and a measurable decrease in performance during the second session.
Carbohydrates and Proteins: Adjusting Quantities to Actual Intensity
A commonly cited distribution for the plate of an endurance athlete is around 60% carbohydrates, 30% proteins, and 10% fats. This base, mentioned in classic recommendations, only works if it is modulated according to the actual training program.
Carbohydrates: The Main Fuel for Effort
Carbohydrates directly fuel muscle contraction during moderate to high-intensity efforts. Light training (walking, yoga, mobility) does not require the same intake as a long run or bike ride.
- Intense or long training day: increase the portion of starches in the meal before the session and include a carbohydrate recovery snack.
- Rest day or light activity: reduce carbohydrates in favor of vegetables, proteins, and healthy fats, without trying to maintain a fixed ratio.
- Day before competition or prolonged effort: gradually increase carbohydrates over 24 to 48 hours to boost glycogen stores.
Proteins: Beyond Muscle Reconstruction
Proteins contribute to the repair of muscle fibers after effort, but their role goes beyond mere recovery. They are involved in the synthesis of enzymes, antibodies, and bone matrix.
For a regular athlete, spreading protein intake across all meals yields better results than a massive dose in the evening. Each meal should include a source of protein, animal or plant-based, to maintain a constant muscle synthesis signal.
Functional Signs of Undernutrition in Regular Athletes
The common trap is not the poor composition of the plate, but an overall intake that is insufficient compared to expenditure. The “performance diets” found online often set quantities without considering individual training volume.
Concrete warning signals, documented within the framework of REDs, deserve systematic attention:
- Fatigue that persists despite sufficient sleep, accompanied by a feeling of heaviness during training.
- Recurring injuries (tendinopathies, stress fractures) that indicate bone weakening due to energy deficit.
- Mood disturbances, irritability, or unusual difficulty concentrating on training days.
- In women: menstrual cycle disturbances. In men: notable decrease in libido.
These signals do not stem from “lack of motivation.” They reflect a discrepancy between energy consumed and energy expended. The answer is not a dietary supplement, but an increase in overall caloric intake, ideally guided by a professional.
The takeaway from the 2023-2026 recommendations can be summed up in one sentence: an undernourished athlete regresses even while training more. Adjusting the plate to the actual volume of effort remains the most direct lever for progress without injury.