Nutrición deportiva: la guía completa para atletas y personas activas

Los carbohidratos son el combustible principal para esfuerzos intensos. La proteína es esencial para la construcción y recuperación muscular. Las grasas son importantes para la resistencia y la producción hormonal.

2-3 horas antes: carbohidratos complejos + proteína (ej. avena con yogur). 30-60 minutos antes: carbohidratos rápidos si es necesario (ej. plátano). Hidratarse bien.

La 'ventana anabólica' de las primeras 2 horas tras el entrenamiento: proteína + carbohidratos para la recuperación muscular y reposición de glucógeno. Objetivo: 20-40 g de proteína + carbohidratos en proporción 2:1.

La creatina (para fuerza y velocidad), la cafeína (para resistencia), la beta-alanina (para tamponar el ácido láctico) y los suplementos proteicos (cuando la dieta no es suficiente) tienen evidencia sólida. Muchos otros suplementos son innecesarios.

Recovery nutrition serves three main purposes: replenishing depleted glycogen stores, stimulating muscle protein synthesis to repair and build muscle, and rehydrating. The classic advice to consume a protein-carbohydrate meal within 30 minutes of finishing exercise ('the anabolic window') has been somewhat nuanced by later research, but the fundamental principle remains valid, particularly for those training twice daily, for those training fasted, or for maximising competitive performance.

For practical purposes, consuming 20–40 g of high-quality protein within 1–2 hours post-exercise is the most consistently evidence-supported recommendation. Whey protein is the most studied and shows particularly rapid absorption and high leucine content that powerfully stimulates muscle protein synthesis. Whole food sources including chicken, fish, eggs, dairy and soy work equally well for most purposes. Pairing protein with carbohydrate (1–1.2 g/kg body weight) accelerates glycogen resynthesis, which is particularly important when training again within 8–24 hours. Chocolate milk, famously, provides a convenient and research-validated ratio of protein to carbohydrate for post-exercise recovery. Rehydration should aim to replace 150% of fluid lost through sweat (body weight before minus body weight after exercise, converted to litres).

For athletes focused on building muscle or maintaining muscle during fat loss phases, protein quality, quantity and distribution across the day all matter. The current evidence supports consuming approximately 1.6–2.2 g of protein per kilogram of body weight per day for muscle development, with some benefit seen up to 2.4 g/kg for those in caloric restriction. Beyond this range, evidence for further muscle-building benefit is weak.

Equally important to daily total is distribution. Consuming protein in three to four doses of 20–40 g spread across the day (rather than the same total eaten predominantly at one meal) keeps muscle protein synthesis elevated more consistently over 24 hours. Pre-sleep protein — 30–40 g of casein or Greek yoghurt before bed — has good evidence for enhancing overnight muscle protein synthesis and improving morning recovery, particularly for those training in the evening. Complete protein sources containing all nine essential amino acids are more effective than incomplete sources (many plant proteins are low in one or more essential amino acids), which is why vegetarian and vegan athletes need to combine protein sources or rely on complete plant proteins such as soy, quinoa or hemp.

Carbohydrate loading — systematically increasing glycogen stores above normal levels by consuming a very high carbohydrate diet (8–12 g/kg body weight/day) for 1–3 days before endurance competition — is a well-validated strategy for events lasting more than 90 minutes. It has been shown to improve endurance performance by 2–3% in trained athletes by delaying glycogen depletion. It is not relevant for shorter events, strength training or recreational exercise.

Regarding supplements, the evidence base is much thinner than the industry suggests. Creatine monohydrate is the most consistently evidence-supported ergogenic supplement for strength and power sports, increasing maximal strength and high-intensity exercise performance through enhanced phosphocreatine availability. Caffeine (3–6 mg/kg body weight 30–60 minutes before exercise) improves endurance, strength and cognitive performance during exercise with a strong evidence base. Beta-alanine can buffer muscle acidity during high-intensity efforts lasting 1–4 minutes, with modest but consistent performance benefits. Sodium bicarbonate has similar acid-buffering effects. Everything else on the sports supplement market — branched-chain amino acids, glutamine, HMB, testosterone boosters, fat burners — has either weak, inconsistent or frankly fabricated evidence behind claimed performance benefits.

The guidance in this article draws on peer-reviewed nutrition and food-science literature as well as guidance from major public-health bodies. Key reference sources we have consulted while writing and updating this piece include:

• Harvard T.H. Chan School of Public Health, *The Nutrition Source*, 2024. • U.S. National Institutes of Health (NIH), Office of Dietary Supplements, fact sheets, 2024. • World Health Organization (WHO), Healthy Diet fact sheet, 2024. • Cochrane Database of Systematic Reviews — relevant systematic reviews, 2020–2024. • British Dietetic Association (BDA) Food Fact Sheets, 2024.

These references are provided so that motivated readers can verify claims and explore the underlying evidence directly. Where a specific trial, meta-analysis, or named author is referenced in the body of the article, that citation takes precedence over the general sources listed here. The article is reviewed periodically against newly published evidence and updated when meaningful new findings emerge.