Why, how much, what and when?
Carbohydrate needs are a widely discussed topic in the media. In times when myths are mixing with scientific knowledge, it is not surprising that many athletes remain unsure of the amount and kind of carbohydrate they need to support their training and optimize performance.
Why do you need carbohydrates?
Our bodies need carbohydrates to function properly. It is needed as fuel for muscles, organs and brain function. Stored in limited amounts in muscles and liver (as the sugary substance, glycogen), carbohydrates are a key source for physical and mental performance, especially during prolonged or high-intensity exercise. When the body stores are depleted (e.g. in high-intensity exercise, prolonged exercise or when the intake is not sufficient), the performance is impacted. Results include physical and mental fatigue, reduced endurance and strength, impaired competition performance, and a reduction in immune system function.
How much do you need?
Carbohydrate intake requirements depend highly on individual factors such as body composition, age and gender; training status, frequency, duration and intensity; as well as performance, training and personal goals.
Intensive Training Needs More Carbohydrates
Daily training intensity varies and carbohydrate intakes need to reflect this. On high-intensity training days, the intake should be increased, while the amount of carbohydrate eaten on low activity days should be reduced. Scheduling carbohydrate-rich foods around high-intensity sessions will help to maximize the training outcome and recovery.
As a general guideline, use the following table reflecting adequate carbohydrate intakes for different training intensity levels.
|Intensity Level||Training Description||Carbohydrate Needs|
|Light||< 1 hour / day
Low-intensity or skill-based activities
|3–5 g per kg / day
1.5-2.3 per lb / day
|Moderate||1-2 hrs / day
Moderate exercise session
|5-7 g per kg / day
2.3-3.2 g per lb / day
|High||2-3 hrs / day
Endurance or high intensity exercise
|6-10 g per kg / day
3-4.5 per lb / day
|Very High||> 3 hrs / day
|8-12 g per kg / day
3.6-5.5 per lb / day
To optimize training and performance, however, a fine-tuning and exact carbohydrate intake must be defined for each athlete individually.
Which foods are good carbohydrate sources for athletes?
All natural, unprocessed foods contain a variety of nutrients that are equally important for physical and mental performance. The amount of essential nutrients per calorie, however, varies significantly for different foods. The higher the nutrient density, the more beneficial is the food for athletes. The following table lists good sources of carbohydrate foods that are high, intermediate or low in nutrients.
|Nutrient Density||Food Sources||Use for Athletes|
|High||whole grain breads, cereal, pasta, rice and grains
fresh, dried and canned fruit, vegetables, potato and corn
fresh, dried and canned legumes, beans and sprouts
low-fat, unsweetened dairy and non-dairy milk and yogurts
|Highly nutritious foods form the base of an athlete’s diet and should be eaten every day. These foods are high in fibers and therefore, should not be eaten less than 3 hours prior to a training session to prevent digestive distress.|
|Intermediate||white and sweetened breads, pasta, grains, cereal, fruit and granola bars
sweetened dried and canned fruit, vegetables and corn
unsweetened juice, smoothies and shakes, sports drinks, gel
sweetened, low-fat dairy and non-dairy milk and yogurts
|These foods should not be a major part of the everyday diet but can be beneficial around training as they provide a compact source of carbohydrates. They can be eaten 1-3 hours prior to training sessions.|
|Low||pastries, cake, cookies, digestives, bars, chips, candy and chocolate
marmalade, jam, fruit gelatin, fruit preservatives
sweetened beverages, sodas, soft drinks and juices
milk shakes, ice cream, frozen yogurt (dairy and non-dairy)
|Foods with a low amount of nutrients per calorie should only be eaten rarely. They provide “empty calories”, i.e. lots of calories but low amounts of vitamins, minerals and antioxidants. They should not be eaten around training sessions.|
When do you need carbohydrates?
Higher levels of training frequency, duration and intensity increase carbohydrate needs. Depending on individual factors, the intake of carbohydrates before, during or after exercise can be optimized. A well-defined dietary strategy ensures that the timing of the carbohydrate is best suited to fuel the training. The following table shows a general guideline to get started with optimizing an athlete’s carbohydrate intake.
|Timing||Physical Performance Situation||Carbohydrate Targets|
|Everyday Base Diet||Daily training < 90 min||7-12 g/kg 0r 3-5.5 g/lb|
|Before Exercise||Before exercise < 60 min
Before exercise > 60 min
1-4 g/kg or 0.5-2 g/lb
|During Exercise||Brief training < 45 min
Moderate 45-75 min
Endurance 1-2.5 hrs
Extreme 2.5-3 hours
< 10 g
Up to 90 g/hr
|After Exercise||If < 8 hrs between two high-intensity sessions||1-1.2 g/kg or 0.5-1 g/lb per hr for first 4 hrs|
In very demanding training situations, such as daily high-intensity training in preparation for competition, carbohydrate loading helps optimizing training results.
In preparation for exercise events that last longer than 90 minutes and require sustained high-level performance, 10-12 g carbohydrates per kg and day (or 4.5-5.5 g per lb) should be consumed for up to 2 days.
This is just a rule of thumb, however, as the concept of carbohydrate loading is highly focused on optimizing performance and must be designed for each athlete individually.
What are the most important facts on carbohydrates and performance?
- Carbohydrates are key for mental and physical performance as they provide fuel for muscles and the brain.
- Good carbohydrate sources for athletes are foods that are high in nutrients, such as whole grain products, fresh produce, legumes and low-fat dairy.
- Depending on the intensity, duration and frequency of the training sessions, different amounts of carbohydrates are required to sustain a high level of performance. The higher the intensity, duration and/or frequency of an exercise, the higher is the need for appropriate carbohydrate intake.
- Additionally, the timing of carbohydrate consummation is highly relevant for training outcomes.
The provided information serves only as a general guideline. For optimizing performance and training outcomes, individual nutrition plans should be designed.