糖的不同种类
Carbohydrates are great foods for athletes. They don't clog your arteries or give you cancer, but carbohydrates don't metabolize at the same rate either.
"If you experience energy lapses during long workouts, experiment with your carbohydrate choices," suggests Kristen J. Reimers, associate director at the International Center for Sports Nutrition in Omaha, Nebraska.
The glycemic index rates the speed at which various carbohydrates are metabolized and their ability to raise blood sugar. Foods that rate high is the list make their energy available after twenty minutes or so, while foods which come in under 35 provide sustained energy. Glucose is the reference point, with an index of 100.
The glycemic response is influenced by the amount of food you eat, its fiber content, fat content or amount of added fat, and the way the food is prepared.
If exercising for longer than an hour or so, load with two grams of low-index carbohydrates per kilogram of body weight. If you eat closer to the workout time, halve the amount. These foods will help to keep your blood sugar level stable through the workout.
Highly glycemic carbs are best just before, during, and after exercise. The sugars from these foods enter the bloodstream quickly to be available to you muscles.
Avoid highly glycemic foods too long before exercise, or pick foods richer in fructose than glusose or the mixture of the two sugars, sucrose. Sugars, and glucose especially, create an insulin reaction when concentrations are boosted without active muscles to eat them up. The result is the carbs that you laboured to scarf down will be bound up in muscle glycogen is your back and arms as well as the legs, rather in your blood ready to be soaked up on the road by the leg muscles you actually use.
Here's how some of everyone's favourite carb-rich foods meet the test:
Sugars
Glucose 100
Honey 73
Table Sugar 65
Starches
Instant Rice 90
Corn Flakes 84
Graham Crackers 74
Cheerios 74
Bagel 72
White Bread 70
Bran Muffin 60
White Rice 56
Oatmeal Cookie 55
Popcorn 55
Brown Rice 55
Spaghetti 41
All-Bran 42
Rye 34
Barley 25
Fruit
Watermelon 72
Raisins 64
Orange Juice 57
Banana 53
Orange 43
Apple Juice 41
Pear 36
Apple 36
Grapefruit 25
Plums 24
Cherries 22
Vegetables
Baked Potato 85
Corn 55
Sweet Potato 54
Chickpeas 33
Green Beans 30
Lentils 29
Kidney Beans 27
Peanuts 15
Dairy
Ice Cream 61
Skim Milk 32
Yogurt 14
