Carbohydrate tolerance depends directly on physical activity and muscle mass ("metabolic flexibility"). For a sedentary person, exceeding a threshold of 40 to 50 g of carbohydrates per meal (or 300 g per day) would disrupt metabolism.

noli's read

The basic physiology is sound: skeletal muscle is the primary site of insulin-stimulated glucose disposal (approximately 80% according to a review published in Circulation Research), and regular exercise optimizes this sensitivity. Data from the American NHANES survey also confirm that the average carbohydrate intake in adults is around 300 g per day. Nevertheless, the idea of a universal "carbohydrate tolerance threshold" fixed strictly at 40 or 50 g per meal is a simplification. Research shows that glycemic response varies considerably from one individual to another depending on genetics, body composition, and sleep. Furthermore, the analogy comparing 300 g of daily carbohydrates to three clinical oral glucose tolerance tests (OGTT) is biologically exaggerated. An OGTT uses 75 g of pure liquid glucose while fasting, whereas the carbohydrates in our meals, which are often complex and consumed with fiber or protein, provoke a much smoother glycemic response. We therefore validate the importance of muscle mass for optimizing energy management, while avoiding overly rigid numerical rules.

the sources

1. 1Gardner CD et al. (DIETFITS) 2018
2. 2Seidelmann SB et al. 2018
3. 3Hu T et al. 2012