The ‘net carb’ hype
If you’re counting carbs and reading food labels, no doubt you’ve come across the term “net impact carbohydrates.” A low number of net carbs implies the food is low in carbohydrates.
However, this unofficial term, created by food companies and not approved or regulated by the U.S. Food and Drug Administration, is more marketing gimmick than nutritional aid. When manufacturers calculate net carbs, they subtract certain carbs that don’t affect your blood sugar—supposedly fiber, glycerin and sugar alcohol—from the total number of carbohydrates. This makes products more attractive to dieters. But glycerin and sugar alcohols actually do raise blood sugar and contribute calories.
Judging from current magazine ads and TV commercials, there seems to be a war on carbohydrates these days. Armed with trendy diets and grocery carts filled with “low-carb” versions of rolls, candy and even beer, we take aim at our dinner tables’ bread and butter, leaving, well, sometimes just the butter. Are carbohydrates really the enemy? Read on to learn what you need to know about this controversial food group.
What are carbohydrates?
Carbohydrates are sugars and starches that convert to glucose, serving as your body’s main fuel and energy source. About 40 percent to 60 percent of your daily calories should come from carbs, though not all carbs are equal nutrition-wise. Some provide lots of vitamins, minerals and fiber; others are little more than empty calories.
Carbohydrates are considered simple or complex. Simple carbs are made up of one or two sugar molecules that convert quickly to glucose and can provide fast fuel for only about 30 to 60 minutes. Simple sugars are found in fruit, milk, juice, candy, cakes, soda and sugar. Because the simple carbohydrates from fruit and milk also provide fiber or vital nutrients, they are healthier than those from sweets.
Complex carbohydrates, made of long chains of sugar molecules, take longer to digest and convert to glucose, so they yield more sustained energy. These carbohydrates are the type found in breads, cereals, pasta, rice, beans, nuts, vegetables and seeds. Most of your carbohydrates should be the complex kind.
The glycemic index
Beyond simple and complex, carbohydrates differ in how they affect the body. The glycemic index measures how fast and high your blood glucose, or sugar, rises after eating a food that contains carbohydrates.
For example, your body very quickly converts white bread you eat to glucose, causing your blood sugar to rise rapidly, so white bread has a high glycemic index. Brown rice, however, digests slowly, causing a gradual and less-pronounced rise in blood sugar, so brown rice has a low glycemic index. Eating a diet filled with high glycemic index foods is associated with a higher risk for diabetes and heart disease.
Because of this effect on blood sugar, choosing “good” carbohydrates is more involved than sorting the simple from the complex. Some complex carbohydrate foods like potatoes can raise blood sugar quickly, and some simple carbohydrate foods like whole fruits raise blood sugar more slowly.
Choose your carbohydrates by seeking whole fruits and whole-grain foods made with whole wheat, whole rye or whole oats.
Are low-carb diets healthy?
The idea behind low-carb diets such as Atkins, Zone and South Beach is that eating carbohydrates spurs insulin production, which leads to weight gain. Therefore, by cutting carbohydrates drastically, you’ll lose weight. What’s more, proponents of these diets say, by limiting the amount of glucose you have for energy, your body will instead burn stored carbohydrates (glycogen) and excess fat.
These diets do help some people lose weight. When you burn glycogen, you release water, and much of what you lose is water weight. You burn some fat, which creates by-products called ketones and a state of ketosis in the body, which can suppress appetite. Additionally, when you drastically limit a major food category, you often slash calories. Anytime you eat fewer calories than you burn—of any kind—you lose weight.
Low-carb diets have their critics who claim too many calories, not a carbohydrate-insulin connection, causes people to gain weight. What’s more, the long-term risks of eating a low-carb diet are not fully known. What is known is that many of the foods promoted in these diets, including beef, pork, cream and butter, are high in saturated fat, which has been found to increase the risk for heart disease and some types of cancer. Plus, low-carb diets call for eating fewer healthy carbohydrates like fruits, vegetables and whole grains, which provide important nutrients that reduce the risk for heart disease and cancer.
One recent U.S. government-funded study of 311 overweight women compared the Atkins diet to three other weight-loss regimens. Those following the Atkins plan lost nearly 11 pounds on average over a year–nearly twice as much as those on the other diets. There was no difference among the women in heart-disease risk factors at the end of the study–all of the women improved their blood pressure and cholesterol levels.
Some experts worry, however, that a prolonged state of ketosis is unhealthy. Aside from contributing to fatigue, nausea and bad breath, it can deplete minerals from your bones, putting you at risk for osteoporosis.
Can you have your carbs and be healthy, too?
Yes! Choose carbohydrates in the form of whole fruits and whole grains and aim to:
- Make grains part of your morning. Enjoy oatmeal or a cold cereal that lists whole wheat, oats, barley or another grain as the first ingredient. Buy or bake your own whole-grain breads or muffins.
- Switch pastas. Substitute whole-wheat pasta for white pasta or noodles.
- Pass on the potatoes. Try brown rice, bulgur, wheat berries, millet, quinoa or hulled barley as a side dish instead.
- Cut out the junk carbs like nutrient-lacking sugars, sweets, sodas and chips.
- Drink alcohol in moderation. No more than one drink a day for women.