Carbohydrate intake is closely associated with sports performance, and the amount required is directly linked to the intensity and duration of exercise. Or Carbohydrate should be consumed pre-exercise, during exercise, and post-exercise during training and competition, each of which will have implications for the effectiveness of physiological responses and adaptations.
Carbohydrate supplements have become common among athletic populations, with numerous commercially available products, including cereal bars, gels, beverages, and powders, considered effective sources for improving endurance exercise performance. Like this different food sources of CHO with different glycemic indices can be more or less efficient for exercise performance and glycogen replacement when recovery time is short. However, the feasibility of implementing each dietary carbohydrate source for pre-exercise, during exercise, and for post-exercise consumption is an important consideration for athletes.
Carbohydrate Intake in Pre-Exercise
Consumption of 1-4 g/kg of carbohydrate is generally recommended 1 to 4 h before resistance exercise. The selection of pre-exercise foods depends on several factors, such as gender, training status, and/or habitual food intake of endurance athletes; nevertheless regardless of individuals’ choices, pre-exercise carbohydrate intake is important. These performance effects were evident for trained athletes, demonstrating that a high-carb pre-exercise meal appears to be better for performance than a low-carb meal or nothing at all.
Recommended traditional food sources are pasta, lentils, potatoes and rice, can be interesting sources of carbohydrates to implement before exercise, although individuals should be cautious about the amount in some of them, as they are relatively low compared to other sources. This means that consuming large amounts of food may be necessary to achieve desired carbohydrate levels and cause gastric discomfort. Bananas can also be considered as a pre-exercise snack to be ingested <2 h before exercise for those athletes who feel hungry near exercise.
Carbohydrate Intake During Exercise
In addition to pre-exercise CHO intake, CHO intake during resistance exercise is considered essential for maintaining performance. When exercise lasts between 1 and 3 h, intake of 30–60 g/h of CHO is commonly recommended. Isotonic CHO drinks containing multiple CHOs at a dose of 60–90 g/h during exercise have been suggested to increase endurance capacity when activity is extended above 3h. These higher doses of mixed CHO (e.g., glucose and fructose in a 2:1 ratio) promote increased carbohydrate absorption through two different intestinal transporters. Endurance athletes tend to prefer transportable CHO supplements such as hydrogels, doses, bars, and chewing during competition due to increased gastrointestinal tolerability, absorption, and oxidation rates. However, endurance athletes may see eating fruits and carbohydrate-rich foods as a natural and cost-effective source to provide during exercise. Of course, an important consideration is that these foods should be easily transportable to an athlete.
Food sources such as bananas, honey and raisins are excellent alternative sources to be ingested during exercise. They are as effective as commercial supplements, such as gels and sports drinks, for improving prolonged endurance performance. However, the higher potential risk of gastrointestinal distress is related to a higher proportion of fructose, fiber content, and amount to meet standard carbohydrate doses. (60–90 g/h).
Post-Exercise Carbohydrate Intake
After resistance exercise, carbohydrate replacement is critical, especially when the recovery time between exercise sessions is limited (<4 h). CHO delivery at 1-1.2 g/kg is recommended to maximize muscle glycogen replenishment and storage to optimize subsequent exercise performance. It is suggested that foods with a high glycemic index are preferable to optimize post-exercise glycogen replacement, mediated by higher insulin responses, which can increase subsequent resistance performance.
Nonetheless the optimization of muscle glycogen during a 24-hour recovery period is more dependent on the total carbohydrate dose intake. Foods with a high glycemic index may be preferable when there is a short recovery period between exercise sessions, while the total carbohydrate consumed seems more critical when longer recovery periods are possible. In addition, it is important to note that carbohydrate co-ingested with protein after exercise can increase glycogen synthesis, but only when the added energy from protein is ingested in addition to, and not as a substitute for.
Clinical practice
A high-carbohydrate diet can optimize muscle glycogen stores and aid in endurance exercise performance. While current recommendations for intake often focus on energy and sports drinks, many athletes may want to take a dietary approach, although it should be noted that there are pros and cons to this approach. In addition to carbohydrate, many of these food sources provide protein, fats and fiber, vitamins, and other micronutrients such as polyphenols, which can also benefit endurance athletes. All carbohydrate sources can be considered interesting as compositions of meal plans during training and during the days leading up to the competition to ensure that muscle glycogen stores are maximized, and with it the foods with a high glycemic index may be better for quickly resynthesizing muscle glycogen after exercise, and therefore should be prioritized during intense competition. However, gastrointestinal discomfort seems more common with some of these food choices, likely due to the large amounts needed to get the recommended carbohydrate doses.
Bibliographic references
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Article: Naderi A, Gobbi N, Ali A, Berjisian E, Hamidvand A, Forbes SC, Koozehchian MS, Karayigit R, Saunders B. Carbohydrate and Resistance Exercise: A Narrative Review of a First Eating Approach. Nutrient. 2023; 15(6):1367. https://doi.org/10.3390/nu15061367
