Читать книгу Peak Nutrition. Smart Fuel for Outdoor Adventure онлайн
82 страница из 87
Carbohydrates and Energy Transfer
The body can store only a limited supply of carbohydrates. If you went without eating, your carbohydrates would be depleted within a day, whereas fats would last you a few days, maybe more. As a result, you need to ingest carbs frequently, but you don’t need a diet high in them to get the energy you need. Glucose can also be broken down from muscle, and you’ll learn later in this chapter how fat can provide you with plenty of energy (known as fat adaptation). Carbs can be used in five different metabolic pathways to provide ATP for movement:
•Glycogenesis: glucose to stored glycogen
•Glycogenolysis: glycogen to glucose
•Glycolysis: glucose to pyruvate
22
•Gluconeogenesis: noncarbohydrates to glucose
GLYCEMIC INDEX
The glycemic index of a food is a measure of how quickly the food increases blood glucose. Table sugar gets a score of 100, and all other foods are calculated relative to this score. Glycemic index can be a useful guide for understanding which foods cause blood glucose spikes; however, it is all relative, and it depends on the serving size of the food and the food combinations. In general, to have a healthy body composition and optimal athletic performance, eat as many foods with a lower glycemic index as possible, such as legumes, vegetables, fruits, and whole grains.