What are carbohydrates?

Carbohydrates are naturally occurring sugars, starches and fiber in food. All carbohydrates are made up of sugar molecules. Sugar molecules linked together form starches and fiber.

In the body, starches and sugars are broken down in the digestive system to glucose. Glucose is the fuel that provides energy and powers all of the body’s functions. Glucose is also called blood sugar.

Dietary fiber is a form of carbohydrate that is not broken down during digestion. It passes through the stomach, small intestine, colon and then out of the body.

Scientists and dietitians used to group carbohydrates into two types: complex carbohydrates and simple carbohydrates. Complex carbohydrates include starches and fiber. Simple carbohydrates include sugar that occurs naturally in fruits, vegetables and milk as well as brown sugar, white sugar, honey and any sugar added to foods during processing.

Today, scientists and dietitians classify carbohydrates based on their fiber content and ingredients.

What are good carbs and bad carbs?

These are terms that different diet promoters have made popular. Usually, good carbs means foods that contain high fiber amounts. Good carbs take longer to be broken down by the body and used for energy. They are found in whole grain breads and cereals, products made from whole wheat flour, vegetables and fruits.

Bad carbs refers to foods that contain refined carbohydrates with a low fiber amount, mainly white flour and sugar. These are found in foods like white bread, cakes, cookies and other bakery items made with white flour; white (processed) rice and some cereals.

Dividing carbohydrates into good carbs and bad carbs is an easy way to think about good nutrition, but these are not exact, scientific terms. When thinking about eating a healthy diet, eat whole grain, high fiber foods rather than enriched, low fiber foods.

How many carbohydrates does a person need in a day?

Instead of counting carbohydrates, dietitians now recommend planning meals using the “Healthy Plate.” At each meal, half of the plate should be filled with fruits and vegetables and a quarter of the plate should be filled with whole grains. (Dietitians do not count potatoes or French fries as vegetables.) The last quarter of the plate should be protein – meat, fish, beans or nuts.

Why are whole grains important?

Whole grains are the best source of carbohydrates because they provide energy plus vitamins, minerals and fiber. Eating whole grains as often as possible instead of highly refined grains, like white flour and white rice, can help reduce the risk of heart disease and diabetes and keep the digestive system healthy. Foods made from whole grains have high fiber content.

Why is fiber important?

Fiber is found in vegetables, fruits, legumes (beans) and whole grains. Fiber promotes a healthy digestive system by keeping the bowels moving. It also can help prevent obesity and reduce the risk of heart disease and diabetes by slowing down digestion and keeping you full longer.

Fiber can be soluble (dissolves in water) or insoluble (does not dissolve in water).

Soluble fiber can be found in most fruits; some vegetables, including corn, peas and carrots; oatmeal and oat bran; nuts, seeds and dry beans. When mixed with water during digestion, this type of fiber becomes a thick, gelatin material. Soluble fiber can help lower cholesterol (related to heart disease risk) and blood glucose (related to risk for diabetes).

Insoluble fiber is also found in a variety of foods, especially foods made with whole wheat flour, wheat bran, brown rice, whole grain cereals, couscous, most vegetables, and fruits. Insoluble fiber helps the body move waste through the digestive system. It also may help prevent small blood clots that can cause heart attacks or strokes.

Both kinds of fiber are important. Adult women should try to eat at least 20 grams of fiber a day. Men should try to eat 30 grams a day. The easiest way to include fiber in the diet is to eat a variety of foods that include raw, whole fruits and vegetables, beans, and whole grain breads, pastas and cereals.

Does eating carbohydrates cause weight gain or make it difficult to lose weight?

That depends. Eating too many calories from any type of food will cause weight gain. But foods with low fiber content often contain a lot of calories without any nutrients. They are metabolized very quickly into glucose. The sudden spike in the blood glucose level triggers the pancreas to produce more insulin, a hormone that promotes fat storage. This means it is easy to gain weight by eating too many of these types of foods.

Foods with high fiber content are metabolized more slowly without causing a big insulin rush. The body can use them as energy over several hours. In general, foods with high fiber content are higher in vitamins and minerals so they are healthier foods to eat.

Is it possible to eat a healthy diet without eating any carbohydrates?

Weight loss is the most common reason why people decide to go on low carb diets. Experts in diet and nutrition agree that a low carb diet can be a good way to jump start weight loss, but it is hard to follow for a long time. Another caution is that many low carb diets include large amounts of unhealthy oils. Low carb diets that are high in animal fat may actually increase the risk of heart disease. And the long term effects of very low carb or no-carb diets are not known. A diet that includes a moderate amount of healthy carbohydrates like whole grain products, fruits and vegetables is the best diet for long-term weight management and health. It is also the easiest kind of diet to follow.

What does a food’s nutrition label tell me about carbohydrates?

Nutrition labels are a good source of information about the kinds of carbs and how much fiber a food contains.

Summary of characteristics of good and bad carbohydrates

Good carbohydrates (High fiber content)

  • Slowly digested (body can use food as energy over several hours). Slowly digested foods result in a gradual increase in blood sugar.
  • Unprocessed foods. Natural ingredients are not removed during the making of the food. Examples include whole grain breads, beans and cereals and products made from whole wheat flour, along with vegetables and fruits.
  • Helps reduce the risk of heart disease and diabetes; helps prevent obesity; and keeps the digestive system healthy

Bad carbohydrates (Low fiber content)

  • Rapidly digested. Rapidly digested foods cause a spike in the level of blood sugar (The spike triggers the pancreas to make more insulin, which is a hormone that makes the body store more fat.)
  • Processed foods. Natural ingredients have been removed or changed during the making (the ‘processing’) of the food. For example, to make white bread, the bran and germ from wheat grain needs to be removed to make the white flour used to make white bread. Other processed food include cakes, cookies and other bakery items made with white flour; white (processed) rice and some cereals.
  • Increases the risk of heart disease, diabetes, and obesity.