CPTIPS Nutritional Program

Nutritional Physiology

How should one eat to get the most out of their training program? There are two issues. First, which type of Calorie (carbohydrate, fat, or protein) is better for you when you are exercising. And second, what is the effects of exercise on the digestive tract, important in deciding when you should eat.


Carbohydrates contain 4.1 Calories per gram (120 Calories per ounce).

Fats contain 9 Cal/gram. Protein is only used as an energy source in malnourished states.

The Bonk

When the body's 1500 stored carbohydrate Calories are gone, only fats are left (plus carbs you eat) At that point, the exercise level drops to 50% VO2 max. at most where fat can provide all the needed Calories. One can avoid the bonk by:


Before we go any further, let's take a minute to discuss the role of the various parts of your digestive tract.

When designing a nutritional program to supplement the body's energy stores for an athletic event, the rate of digestion and absorption of foods must be taken into account. The time needed for:

will directly affect how quickly any food will be available to the muscle to provide the supplemental Calories for exercise.

Emptying of the stomach into the small intestine is the rate limiting step in getting Calories into the blood stream and to the working muscles. Once food molecules get into the small intestine, they are absorbed quite quickly. You have control over four major factors that can delay stomach emptying.

From the above four points, it is easy to see that the optimal food for a rapid, high-energy boost during a ride would be a semi-liquid or liquid carbohydrate with minimal if any fat. On the other hand, an endurance athlete, competing at a lower VO2 max., might prefer a complex carbohydrate with some fat added to improve taste (and generally in a solid form), in order to slow emptying from the stomach and even out absorption over a longer period of time.

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