Good Carbs and Bad Carbs

Good Carbs and Bad Carbs

Carbs can be confusing. Filled with misinformation and hype, television commercials and Internet advertisements talk about good carbs and bad carbs, added sugars, the glycemic index, fiber and whole grains.

Which do you need and which should you avoid?

We'll clear the confusion and fill you in on the true identities of the good and bad members of the carbohydrate family as we explain the role of carbohydrates in a heart healthy diet.

What is a carbohydrate?

All carbohydrates share a single basic property: in the body they can be converted to sugar—specifically, glucose. That's the definition of a carbohydrate.

Simple carbohydrates are those that are digested and absorbed quickly, best represented by sugars themselves. Complex carbohydrates include starches. While many believe that dietary starches cause a slower rise in blood glucose levels than do simple sugars, this is incorrect. Many starchy foods—white bread and baked potatoes, for example—cause rapid and large increases in blood sugar, just like simple sugars.

Is sugar bad for you?

Your body requires 200 grams of sugar per day, and sugar is the primary fuel for your brain. But sugar has been vilified of late, particularly in the discussion of added sugars. Added sugar is any caloric sweetener that is added to a food as it is prepared or processed.

So if pineapple, which contains natural sugars, is sold in a can that contains syrup, the syrup includes added sugars. Primarily because of our love affair with sugar-sweetened beverages, Americans consume an average of 21 teaspoons of added sugar each day, amounting to an astounding 16 percent of our total calories. Added sugars are everywhere; they hide out in ketchup, barbecue sauce, cream substitutes, many reduced-fat salad dressings and granola bars.

Although added sugars are chemically the same as naturally occurring sugars, they are not an innocent part of our diets. They provide empty calories—those with no nutritional value. Excess added sugar in the diet is associated with obesity, diabetes, hypertension and an unfavorable lipid profile that includes reduced HDL cholesterol and increased triglycerides.

Limit your added sugars. For women, this means no more than 100 calories per day of added sugars (6 teaspoons) and for men no more than 150 calories per day (9 teaspoons). For reference, a 12-ounce can of regular soda has 8 to 10 teaspoons of added sugar and a serving of a standard breakfast cereal has about 4 teaspoons.

The glycemic index: Carbs get complicated

In 1981, a researcher named David Jenkins added to the confusing lexicon of carbohydrate terminology with his development of the glycemic index. The glycemic index ranks carbohydrates according to the rise in blood glucose that occurs after a food is eaten. Foods with a high glycemic index cause large and rapid increases in blood glucose. Refined carbohydrates—such as sugar-sweetened beverages, candy, cakes, white bread, white rice and potatoes—generally fall into this category. Foods with a low glycemic index cause smaller increases in blood glucose. Low-glycemic-index foods include those made from whole grains and most fruits and vegetables. The key question is this: does the glycemic index influence heart health.

We have some data to suggest that high-glycemic-index carbs might be "bad carbs." Heavy consumption of foods with a high glycemic index is associated with adverse changes in the lipid profile, including elevated triglyceride levels and reduced HDL cholesterol. There is also some evidence that a diet rich in high-glycemic-index carbohydrates increases the risk of developing diabetes. But at this point there is no clear evidence that the glycemic index of foods has major effects on heart health. As a consequence, the 2010 United States dietary guidelines recommend that we not focus on the glycemic index of foods. Rather, when considering carbohydrates, the guidelines suggest that we keep it simple: focus on total calories and fiber content while limiting added sugars. We agree.

Good carbs: Whole grains and fiber

When it comes to carbohydrates and heart health, the key distinction is between whole grains, which tend to be high in fiber, and refined grains, which are generally low in fiber. This leads to our definition of "good carbs" versus "bad carbs." Good carbs are whole-grain foods with high fiber content. Choose relatively low-calorie, high-fiber carbohydrates, including whole grain products, fruits and vegetables. Avoid bad carbs—those that are highly refined, high in added sugar and low in fiber.

How can you tell if something contains sufficient amounts of whole grain? Check the ingredient list on the label. The first ingredient should be "whole grain," such as whole-grain oats, whole-grain wheat, whole-grain rice, whole-grain corn or whole wheat.

Good carbs and heart health

Large, population-based studies suggest cardiovascular benefits for diets rich in whole grains and fiber. Increased intake of whole grains is associated with decreases in body mass index, total cholesterol, LDL cholesterol and fasting insulin levels. Soluble fiber (found in oat meal, beans, peas, citrus fruits, strawberries and apples) can cause a modest reduction in LDL cholesterol and should be included in everybody's diet.

Aim for at least three servings of whole grains per day to reduce your risks of cardiovascular disease and diabetes. Do this by making virtually all of your grains whole grains. Don't be fooled by the color of breads—just because bread is brown does not mean that it is high in fiber. The addition of molasses or brown sugar to bread makes it brown but does nothing to enhance its fiber content.

The decision to enrich your diet with whole-grain, high-fiber foods does not mean that you have to limit yourself. The wide variety of available high-fiber, whole-grain foods ensures a satisfying and variety-filled carbohydrate presence in your diet.

Tasty Whole Grains

  • Toasted oat cereals

  • Shredded wheat

  • Barley Buckwheat

  • Bran flakes

  • Low-fat granola

  • Oatmeal Brown and wild rice

  • Popcorn

  • 100-percent whole-grain bread and crackers

  • Rye bread

  • Whole-wheat pasta

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