What it is: Carbohydrate Loading, or Carb Loading, is increasing the amount of carbs in an athletes diet in order to prepare for an event. Increasing the amount of carbs in ones diet will allow the athlete to increase the fuel stored in their muscles to perform better in athletic events. Carb Loading is primarily used for endurance activities (90+ minutes) where the body will need extra energy to prevent the athlete from hitting `The Wall`.

How it works: Carbs are essentially sugars, so when your body breaks down these sugars they are used for energy. The sugar travels into your blood stream where it will proceed to individual cells to give them energy. If the sugar is not used it is stored in the liver or in muscles as glycogen. Glycogen is used by muscle during exercise for energy. 
Carb loading is the idea of draining the muscle of glycogen so the body would compensate by absorbing more glycogen when replenished.

What To Do: Approximately 1 week before the event the athlete should adjust their diet to make 50-55% of their diet Carbohydrates while maintaining normal exercise intensity/volume. This will help deplete glycogen stores and get the body ready for the loading phase, while not physically exhausting the individual.

3-4 days before the event the athlete should adjust their diet again, but this time increase their carbohydrate consumption to 70% of their daily caloric intake. At this point they would also want to reduce fat intake due to the feeling of being full it gives the individual. During this phase the athlete should reduce the amount of exercise being performed. Athletes should perform low intensity/volume workouts throughout this period up until the day before the race, when they should rest. 
Carb Loading can help the athlete feel less fatigued through the race and improve their performance.

Does It Always Work? A simple answer is no, Carb Loading doesn’t always work. Every person is different and will respond differently to the process based on many different factors (Level of fitness, Body Response to insulin, etc.). Females especially may not benefit from carb loading, there have been mixed results in studies, which have been attributed to females’ menstruation cycles and have been shown that they may need to increase their caloric intake as well. Males on the other hand have been shown that the glycogen stores in their muscles could increase any where from 25-100%, but is not guaranteed.

While there are possible gains from Carb loading there are some set backs as well. A big one people will notice is a slight increase in weight. This is due to the extra glycogen and water your body is absorbing during this process. Another potential issue is a change in blood sugars due to all the extra carbs ingested, which makes Carb loading dangerous for diabetics. Diabetics should consult with their doctor before attempting a Carb Load.

Other Dietary Considerations:
Proteins: Protein will add additional energy as well as slow carbohydrate digestion by lowering the Glycemic Index of each meal. This will slow the release of sugar into the bloodstream, which will supply the athlete with ongoing energy throughout the event.

Fiber: Watching the intake of fiber is key for carb loading. An excess of fiber can create digestive issues before and during race day. Fiber also absorbs fluids, swells up and takes up room in the digestive system, which creates a feeling of fullness in the athlete. The fullness will prevent the athlete from consuming an adequate amount of Carbohydrates.

Fat: Reducing the amount of fat in a diet will also be key due to the fact that it also creates that feeling of being full. Fats can also make the athlete sluggish on race day due to the density of the macronutrient. 

People also make the mistake of thinking increasing carbs gives them a free pass to eat anything they want (Chips, Chocolate and other Junk foods), but watching the type of calories and carbohydrates you consume is just as important as the amount you consume. 

There is not magic formula to a better performance; nothing will replace hard work and dedication in the gym and with nutrition. Carb Loading can help well-trained athletes improve their performance for their athletic events.

Rich Hill

CSEP – Certified Personal Trainer (2011-Current) 

RK Athletics – https://linktr.ee/RK_Athletics