Sports nutrition refers to the adaptation of diet to the physiological constraints imposed by training and competition. It is based on a measurable principle: providing the body with enough energy and nutrients to cover actual expenditure, without deficit or excess. Before discussing foods or supplements, this energy equation conditions everything else.
Energy availability: the parameter most programs ignore
The distribution of macronutrients and the choice of foods occupy most discussions about sports dietetics. However, total caloric intake remains insufficient compared to training load for a high proportion of practitioners.
This imbalance has a technical name: low energy availability (LEA). A meta-analysis published in 2024 in Sports Medicine, covering 46 studies and more than 6,100 athletes, shows that about 45% of athletes have too low energy availability. The phenomenon affects both men and women.
The consequences go beyond simple fatigue. LEA is associated with the RED-S syndrome, which includes hormonal disturbances, decreased bone density, weakened immunity, and a direct decrease in performance. An amateur athlete who increases their training volume without adjusting their intake is exposed to the same risks as a professional athlete.
Adapting sports nutrition first requires checking that the available energy (calories ingested minus calories expended during effort) covers basic physiological functions. The resources available on sports nutrition on Profil Sport allow for a deeper exploration of this often underestimated aspect.
Carbohydrates and proteins: adjusting quantities to the nature of the effort
Carbohydrates remain the primary fuel for intense muscle work. During prolonged effort (running, cycling, long-distance swimming), liver and muscle glycogen stores are depleted. Replenishing these stores between sessions is essential for the ability to continue training without degradation of quality.
Needs vary according to intensity. A moderate endurance effort does not engage the same pathways as high-intensity interval training. Strength sports consume less glycogen but generate micro-muscle damage that increases protein demand for recovery.
Proteins and muscle recovery
Proteins play a role in the synthesis and repair of muscle fibers after effort. Their role is not limited to mass gain: they also contribute to maintaining the immune system, which is particularly stressed in regular athletes.
The distribution throughout the day is as important as the total quantity. Concentrating protein intake in a single meal limits assimilation. Spreading sources (meat, fish, eggs, legumes) over three to four meals optimizes muscle protein synthesis continuously.
Nutrition timing: when to eat around training
The timing of food intake influences perceived performance and recovery. A meal rich in complex carbohydrates consumed two to three hours before effort allows time for digestion and fills glycogen stores. Too close to the session, a heavy meal causes digestive discomfort that reduces possible intensity.
During effort, nutrition only concerns sessions lasting over an hour at sustained intensity. Below that, water is sufficient in most cases. Beyond that, simple carbohydrates (dried fruits, gels, carbohydrate drinks) maintain blood sugar levels and delay fatigue.
The post-effort window
The 30 to 60 minutes following exercise represent a period of heightened sensitivity for glycogen replenishment and the initiation of muscle repair. A combination of carbohydrates and proteins during this window accelerates recovery, especially when two sessions are planned in the same day.
- Before effort: complex carbohydrates (rice, pasta, oatmeal) two to three hours prior, with a source of lean protein.
- During long effort: small amounts of simple carbohydrates every 30 to 45 minutes, accompanied by water or an isotonic drink.
- After effort: a combination of carbohydrates and proteins within the hour following, for example, yogurt with fruit or a portion of rice with chicken.
Gut microbiota and sports performance: a recent avenue
Recent research establishes a link between the composition of gut microbiota and performance capacity. The gut flora is involved in nutrient absorption, inflammation management, and the production of certain metabolites used as an energy source by muscles.
Endurance athletes have a distinct microbiota from that of sedentary individuals, with a broader bacterial diversity. Diet directly influences this diversity: fibers from vegetables, fruits, and whole grains nourish beneficial bacteria.
The use of multi-strain probiotics is the subject of specific studies in the sports context. Published results suggest an effect on reducing upper respiratory infections and on digestive comfort during effort, two factors that indirectly affect training regularity.
- Diversify sources of dietary fiber (legumes, whole grains, varied vegetables) to support bacterial diversity.
- Limit ultra-processed foods, whose negative impact on microbiota is documented.
- Consider a multi-strain probiotic during periods of high training load, after consulting a healthcare professional.
Effective sports nutrition is not limited to a list of recommended foods. The balance between energy intake and actual expenditure, the choice of the right time to eat, and attention to gut health form a coherent whole. A chronic energy deficit remains the most common barrier to progress, well before the lack of any particular nutrient.
