Exercise and carbohydrate-rich diets

In exercise, carbohydrate-rich diets are often recommended to promote recovery and maximise performance.

However, research suggests such foods may not help exercise recovery. There is also a potential link with carbohydrate-rich foods and metabolic diseases.

Since late 1960, the energy status of muscles is deemed to be important in exercise performance.

Since carbohydrate is the preferred energy source for muscle contraction during intense exercise, sports nutrition guidelines recommend eating carbohydrate-rich food to maximise performance. The guidelines suggest eating one gram of carbohydrate for every kilogram of your body mass, each hour for four hours.

• Recovery describes the processes inside the muscles that are stimulated by the stress of exercise sessions. These processes build up and result in increased endurance and muscle growth.
• Exercise performance describes the ability to perform exercise at a specific intensity and duration.

The current nutritional recommendations for performance may not be ideal for promoting recovery.

Researchers have recently observed that limiting carbohydrate intake close to endurance training sessions might promote early muscle recovery and possibly long-term improvements in endurance.

• Studies show high carbohydrate intakes can suppress the activation of several genes linked to exercise adaptations.
• Eating large amounts of carbohydrate during early recovery may also interfere with fat loss.
• Restricting carbohydrates during recovery from exercise increased fat metabolism and decreased carbohydrate metabolism.

Consuming protein when doing resistance exercise is known to benefit muscle growth. Dietary carbohydrate plays little to no role in recovery from resistance exercise.

While high carbohydrate intake have traditionally been recommended to support resistance exercise performance and recovery, several studies now show that it does not further benefit recovery processes compared to protein alone.

Carbohydrates have a potential role in the development of metabolic diseases, including type 2 diabetes and obesity.

Carbohydrate-rich food is thought to overstimulate the hormone insulin by causing chronically high blood sugar levels. One of the roles of insulin is blocking the use of fats as a fuel source. Insulin also promotes the storage of excess carbohydrate as fat and reduces the body's ability to control blood sugar levels. Eating a high-carbohydrate diet may increase fat mass and decrease muscle mass.