Carbs to Love
Jill Weisenberger, M.S., R.D., C.D.E.
Her Sports + Fitness
The low-carb craze that threatened to wipe bakeries off the map and force fruit farmers into bankruptcy is finally over. Once again we can sip smoothies and enjoy a plate of pasta without the fear of carb-loathers arguing in favor of bacon-wrapped, bun-less double cheeseburgers.
You weren't fooled, though. You've always known carbs are your muscles' best fuel and without enough, your 5k race would be more like a three-mile death march. But not all carbs are created equal: Some will give you a boost of energy while others can wipe you out. What's best? Read on to learn how to make carbs work for you.
Body's Best Fuel
Of the three major nutrients your body uses for energy—carbohydrates, fat and protein—carbs are the most easily accessible form of fuel. During digestion, carbs are broken down into glucose (the most basic sugar molecule), quickly absorbed into the bloodstream (protein and fat molecules take longer to convert to blood sugar) and picked up by your body's other cells to metabolize into energy. Glucose that isn't used immediately is turned into glycogen and stored in the muscles for the short-term, or converted to body fat for the longer-term.
Carbs are commonly categorized as "simple" or "complex." Made of a single sugar molecule or two linked together, simple carbohydrates include lactose (milk sugar), fructose (fruit sugar) and sucrose (table sugar). Complex carbohydrates such as starch and fiber in grains and other plants are long strings of sugar molecules. Years ago some people claimed simple carbs were bad and complex carbs were good. But in reality, it's far more complicated. Whether or not a carbohydrate food has much health value has more to do with the nutrients it contains and the amount of processing it's undergone, than with the length of its sugar chain.
Good Choices
Potato chips or fresh mango? Not hard to guess mango is the better carb for your health. Both supply energy for your muscles and brain, but only the mango is packed with disease-fighting, energy-sustaining nutrition. Most of your carbohydrates should come from unprocessed or minimally processed fruits, vegetables and whole grains; low-fat and skim milk; and legumes such as peas, beans and lentils.
Each athlete is different, but generally "women athletes should consume 55 to 70 percent of their calories from carbohydrates," says sports nutritionist Tara Gidus, spokesperson for the American Dietetic Association. An endurance athlete, who needs plenty of carbs to burn, should be at the higher end of the range, whereas an athlete whose focus is on weight training should eat toward the lower amount. If your diet is 2,000 or so calories, aim for about 275 to 350 grams per day of carbs depending on your level of cardiovascular activity. For 2,600 calories, your carb intake might span 355 to 455 grams.
If you're not sure if you're eating the right amount, registered dietitian Nancy Clark, author of Nancy Clark's Food Guide for Marathoners: Tips for Everyday Champions, suggests eyeballing your plate. Two-thirds should be covered with healthy carbs, she says. Or go further and log your daily food choices into an online journal—fitday.com or calorieking.com—that calculates your intake of carbohydrates, fats, vitamins and more.
Fruits and vegetables What really bugged nutritionists during the low-carb years was that people were eating less of the healthiest foods of all—fruits and veggies. Bad idea. A recent report issued jointly by the World Cancer Research Fund and the American Institute for Cancer Research suggests that diets with five to 10 servings of fruits and vegetables daily could prevent at least 20 percent of all cancers. Other research indicates that every one serving increase per day of fruits and veggies is associated with a four percent lower risk of coronary heart disease. Higher intakes of fruits and veggies are also linked to greater bone density.
Whole grains The bread-bashers back then rarely distinguished between the good, made of whole grain, and the not-so-good, made of refined grains. Whole grains contain all three parts of the kernel: The bran is the outer shell that holds B vitamins, fiber and at least half of the grain's minerals. The germ, the seed's nourishment, stores more B vitamins as well as vitamin E, healthy fats, minerals and phytochemicals. Finally, the endosperm, the largest part, contains carbohydrates, protein and smaller amounts of Bs. The milling process removes the germ and bran, leaving only the endosperm. This leaves a refined and much less nutritious grain, such as white flour or white rice.
As few as three servings per day of whole grains could slash your risk of both diabetes and coronary heart disease by as much as 30 percent. Studies suggest that eating whole grains lowers blood pressure, serum triglyceride levels and even your risk of developing gum disease.
On labels look for "100% whole grain" and read the ingredients list to be sure that whole grains are at the top. In addition to whole wheat, try barley, brown rice, buckwheat, bulgur wheat, corn (including popcorn), millet, oats (including oatmeal), quinoa and wild rice.
Low-fat and nonfat yogurt and milk Lower your blood pressure and protect your bones with these carbs. The 2005 Dietary Guidelines for Americans recommends three servings of dairy each day to supply adequate calcium, protein, riboflavin (a B vitamin) and vitamin D. But don't go with yogurt alone; although it's a great source of calcium and protein, yogurt lacks vitamin D. Get your D from milk (or from D-fortified cereals and O.J., if milk gives you problems). And though cheese doesn't usually contain carbohydrates or vitamin D, it also falls into the dairy group and can provide ample nutrition. Watch the fat content of your dairy. Too much saturated fat is bad for your heart.
Beans They're good for your heart and for staving off cancer. Studies suggest they can lower cholesterol, stabilize blood sugar, prevent constipation, decrease the risk for coronary heart disease and the recurrence of advanced colon cancer. They're packed with fiber, protein, folate, potassium, magnesium and a slew of other minerals. Eat three cups a week according to the Dietary Guidelines. Mix them with jarred salsa and corn, stir them into soups and stews, toss them in your salads and spread hummus on whole grain crackers.
Understanding the Glycemic Index
The glycemic index (GI) ranks carbohydrate foods by their effect on blood glucose levels. High GI foods like corn flakes and graham crackers elicit a greater increase in blood glucose—making more energy available to your muscles more quickly—than low GI foods such as apples, beans and yogurt. However, controversy surrounds the usefulness of the GI because the blood-sugar effect varies depending on the amount of food eaten, how it's prepared, and each person's individual response.
Despite its limitations, nutritionist Gidus suggests that an athlete fine-tune her food intake with the GI. "I recommend eating low-GI foods before exercise to provide a more sustained energy release. Moderate- to high-GI foods are best during and post-exercise for immediate repletion of glycogen," she says.
- Before: apples, plums, cherries, peanut butter, milk, yogurt
- During: grapes, sports drinks and gels
- After: bagels, potatoes, juices, sports drinks and gels
The GI doesn't tell it all, however. It measures the effect that 50 grams of carbs in a particular food has on blood sugar, but it doesn't factor in the relative amount of carbs in an average serving of that food. That's why some nutritionists use the glycemic load (GL) instead. Watermelon, for example, has a high-glycemic index because 50 grams of carbohydrate in the fruit has a large effect on blood sugars. But since a typical slice contains only about 6 grams of carbs, watermelon's GL and it's effect on blood sugar is small. The same is true for carrots. They have a high GI, but a low GL.
For more info and to find out GI/GL values of certain foods, search the GI Database on glycemicindex.com. Experiment with different pre- and post-exercise meals to learn your best strategy. The glucose response varies from person to person and even from meal to meal.
Jill Weisenberger, M.S., R.D.,C.D.E, is a registered dietitian and certified diabetes educator for Hampton Roads Center for Clinical Research in Norfolk, Va.
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