Sometimes athletes gather together and feast on copious amounts of bread and pasta: it’s an All-You-Can-Eat Carb Dinner. This is so that they can load up on carbohydrates, or in other words, carb-load.

Carb-loading means increasing the amount of glycogen (by eating carbohydrates) in the body that helps people to endure a longer and more intense amount of physical activity before hitting “the wall”. Glycogen is stored glucose (sugar). It is the body’s first-line energy source for harder physical efforts and keeping specific bodily systems (the brain, red blood cells, the kidney) running efficiently daily.

Contrary to popular belief that extra carbs need to be consumed before exercise, the body can actually restore its own glycogen storage for physical output that does not exceed 90 minutes. All you need is a protein-rich snack after your workout to aid the glycogen refueling process. Keep in mind that the body does not rely solely on carbs for energy; it also uses up stored fats. However, consuming protein immediately (within an hour) of exercise has been shown in studies to promote increases in lean body mass, strength, muscle enlargement, and decreases in body fat. An ideal supplement should contain a source of protein that provides at least 3 grams of leucine (amino acid in most protein-rich food and beverages). Carb intake that is not consumed directly after workouts will generate insulin rushes, which then promotes fat storage since glycogen storage is full. The insulin will then lock fat inside fat cells. On the other hand, protein synthesis is actually more effective when insulin is present. Thus, combining carbs with protein will help build muscle most effectively. Furthermore, timing protein intake (for post-exercise) will increase muscle mass much more than periodic smaller doses of protein at any other time.

So how do you know if carb-loading is for you? Carb-loading is only necessary for exercise that lasts for 90 minutes or more. It is not restricted to any sport, as long as it reaches that time minimum. Popular as this method of dietary training is for marathons and triathlons, carb-loading can also be useful for weightlifting sessions, but conditionally so. One study shows that carb-loading before weight lifting increases the amount that athletes were able to lift before hitting “the wall”. However, another study shows that there was no difference in lifters’ power output post carb-loading, possibly because the participants weren’t lifting for long enough to reach exhaustion. Therefore, carb-loading should only be done for strength/weight training and weight lifting if the session will continue over upwards of 90 minutes and exhaustion is anticipated. Otherwise, shorter sessions will not require, or benefit from consumption of additional carbohydrates.