Evaluación de carbohidratos sobre la hipertrofia muscular inducida por el entrenamiento de fuerza: una revisión narrativa de la evidencia científica

Muscle hypertrophy is one of the main physiological adaptations induced by resistance training and depends on the interaction among mechanical stimuli, nutrient availability, and the regulation of multiple intracellular signaling pathways. Although carbohydrates have traditionally been considered essential for stimulating muscle growth by increasing insulin secretion, recent scientific evidence has shown that their contribution is primarily indirect and is related to maintaining performance and energy availability during exercise. The

Aim: of this study was to analyze the effect of carbohydrate intake on resistance training-induced muscle hypertrophy by integrating physiological, biochemical, and molecular mechanisms. A narrative review of the scientific literature was conducted by searching for articles published between 2013 and 2026 in PubMed/MEDLINE, Scopus, Web of Science, SPORTDiscus, and ScienceDirect. Clinical trials, systematic reviews, meta-analyses, and position statements evaluating the effects of carbohydrate intake on muscle hypertrophy, muscle protein synthesis, resistance training performance, and molecular mechanisms involved in the regulation of energy metabolism were included. The evidence analyzed comprised 15 key studies, including 3 systematic reviews, 2 meta-analyses, 7 narrative reviews, 1 experimental study, and 2 position statements. Recommendations for strength-trained athletes range from 3 to 7 g of carbohydrate/kg of body weight/day, depending on training volume and intensity. Furthermore, muscle glycogen stores may range from 300 to 700 g in trained individuals, and high-volume resistance training may reduce these stores by 24–40%, potentially impairing performance when glycogen replenishment is insufficient. The studies analyzed consistently indicate that adequate carbohydrate intake promotes glycogen resynthesis, maintains ATP production, reduces fatigue, and enables athletes to sustain a higher training volume. In contrast, when protein intake and total energy intake are sufficient, the addition of carbohydrates does not independently increase muscle protein synthesis or muscle mass gains, because mTORC1 activation depends primarily on the availability of essential amino acids, particularly leucine. Carbohydrates do not directly stimulate muscle hypertrophy; however, they are essential for maintaining energy availability, promoting glycogen resynthesis, and preserving performance during resistance training. Their effect on muscle growth is primarily indirect, as they facilitate greater training volume and intensity. Therefore, carbohydrate intake should be individualized according to training demands and the specific needs of each athlete.