Carbohydrates and Endurance Sports: Nutritional Strategies

Carbohydrates: an essential macronutrient

Carbohydrates are one of the three major macronutrients essential to the body, along with proteins and fats.

From a biological perspective

It is a molecule composed of carbon, hydrogen, and oxygen, which can be more or less complex depending on its structure.

When you consume carbohydrates, your digestive system primarily converts them into glucose, a simple form of sugar that circulates in the blood.

The two main types of carbohydrates

Not all carbohydrates are created equal. They are generally classified as: simple carbohydrates and complex carbohydrates, based on their chemical structure.

• Simple carbohydrates

Also known as fast sugars, they are composed of one or two sugar molecules. Their effect on blood sugar is rapid but short-lived.
- Glucose: a form of sugar directly usable by the body
- Fructose: sugar naturally present in fruits
- Galactose: present in dairy products
- Sucrose: table sugar (glucose and fructose)
- Lactose: milk sugar (glucose and galactose)

• Complex carbohydrates

They consist of longer chains of sugar molecules (polysaccharides). They release glucose gradually.
- Starch: present in cereals, potatoes, legumes,
- Dietary fiber: although it is not digested to produce energy.

Carbohydrates in the body

Carbohydrates play a central role in the composition of daily nutritional intake. Their regular consumption, in appropriate quantities, is generally taken into account in a balanced diet, especially when they are part of a varied diet.

But to fully understand their usefulness, it is essential to know what happens to carbohydrates once consumed, and where they act in the body.

What happens to carbohydrates after ingestion?

1. Digestion in the small intestine

• Carbohydrates are broken down into simple sugars (mainly glucose) by digestive enzymes such as amylase.
• This glucose is then absorbed by the intestinal wall to enter the bloodstream.

2. Distribution by the blood

• Once in the blood, glucose is transported to cells via the hormone insulin, secreted by the pancreas.
• Glucose is then used as immediate fuel by muscles, the brain, and other organs.

3. Storage as glycogen

• When glucose intake exceeds immediate needs, the body stores the excess as glycogen, mainly in:
  - The liver,
  - The muscles.

4. Conversion to fat (if chronic surplus)

• If glycogen reserves are already full and carbohydrate intake is repeatedly excessive, glucose can be converted into reserve fats through a process called lipogenesis.

The main roles of carbohydrates

The main role of carbohydrates is to be transformed within the body into simple molecules, such as glucose, which are then used in various cellular mechanisms. These molecules are regularly mobilized when the body is active or subjected to certain stresses, which explains their place in most dietary models, particularly in relation to physical activity.

Glucose provides its benefits to the body especially for:
- The brain, which depends almost exclusively on it,
- Muscles, especially during high-intensity or long-duration physical exertion.

Carbohydrates in physical activity

In the context of endurance physical activity, carbohydrate intake can be organized at different times, depending on the needs related to the planned effort, its duration, and its intensity.

It is common to include carbohydrate sources before a session. This consumption can be adjusted according to the time between the meal and the start of the activity, as well as individual digestive tolerance.

During prolonged effort, especially when it exceeds a certain duration, it is also possible to consume carbohydrates during the activity, in forms compatible with exercise (dextrose, powdered fructose, etc.).

Finally, it is common to include carbohydrates after exercise, as part of a meal or snack, taking into account the nature of the session, its objectives, and personal eating habits.

These three moments (before, during, after) are generally considered when developing nutritional strategies related to endurance sports.

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The 8 foods richest in carbohydrates

It is essential to choose your sources of carbohydrates wisely. Not all carbohydrates are equal, and some foods are particularly rich in quality carbohydrates, adapted to the energy needs of athletes. Here is a selection of the ten foods richest in carbohydrates, accompanied by the best time to consume them as part of a training session or competition.

• Cooked white rice or rice cream
  Recommended time: after effort
• Cooked pasta (white or whole wheat)
  Recommended time: before effort
• Potatoes (steamed or mashed)
  Recommended time: after effort
• Oat flakes
  Recommended time: before effort
• Bananas
  Recommended time: during effort
• Dates
  Recommended time: during effort
• Whole wheat bread or white bread
  Recommended time: before effort
• Cereal bars (simple, not enriched)
  Recommended time: during effort

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Carbohydrate supplementation

Depending on eating habits, diets followed, or personal goals, some people choose to use food supplements containing carbohydrates, especially in the context of prolonged or structured sports activity. Among the most frequently used food supplements are:

• Cyclic dextrin
• Maltodextrin
• Glucose powder
• Fructose powder
• Carbohydrate mixtures in gel or drink form
• Effort-specific carbohydrate bars

These products can be consumed at different times of the day, but it is advisable to incorporate them around training and more precisely during training.

Example of a nutritional plan for an endurance athlete

This model illustrates a possible organization of carbohydrate intake over a day including an endurance session. It can be adapted according to individual preferences, objectives, and the duration of the activity.

1. Before effort (approximately 2 to 3 hours before activity)

Objective: plan a meal containing carbohydrates, in moderate quantity, well tolerated by the digestive system.

• Basmati rice, rice cakes with fruit puree or rice cream,
• Pasta, whole wheat bread with jam,
• Oat flakes with a plant-based or dairy drink,
• Bananas.

2. Just before effort (30 to 60 minutes before)

Optional: depending on the duration and intensity of the exercise. Light portion.

• Unsweetened compote,
• Slice of white bread with honey,
• Ripe banana,
• Drink containing maltodextrin or cyclic dextrin.

3. During effort (for effort lasting more than 90 minutes)

Fractionated intake: depending on tolerance.

• Carbohydrate drink (with cyclic dextrin, maltodextrin or glucose),
• Carbohydrate gels,
• Dates or dried figs,
• Simple cereal bars.

4. After effort (within 30 to 60 minutes after activity)

Meal or snack containing carbohydrates associated with other macronutrients according to habits.

• Steamed potatoes or mashed potatoes,
• White rice or Thai rice,
• Bread with savory or sweet accompaniment,
• Pasta with vegetables,
• Fruit and oat flake smoothie.

Carbohydrates and endurance sports, nutritional strategies: in summary

In endurance activities, carbohydrates play an important role in nutritional intake. Their integration into the daily diet, as well as their organization around effort (before, during, after), can be the subject of strategies adapted to each individual.

Depending on dietary preferences, training level, effort duration, or logistical constraints, carbohydrates can be consumed in different forms: natural foods, homemade drinks, or food supplements.

Whether as part of a structured meal before a long outing, a carbohydrate drink during prolonged effort, or a planned intake after an intense session, these nutritional choices adjust to sports practices and personal goals.