What a Carb Is and Its Different Meanings

A nickname for carbohydrate can have a variety of meanings

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The word carb is short for carbohydrate. It is one of the three primary macronutrient components of food, with the other two being protein and fat. Carbohydrates include starches and sugars that are digested and used for energy in the body. The energy value of digestible carbohydrates is 4 calories per gram for sugars and starches.

Carbohydrates are made of carbon, hydrogen, and oxygen. They can be simple sugars or they can be complex starches. Plants and dairy products are the chief sources of carbohydrate in the diet. Refined sugar added to drinks and other products is usually produced from plant sources.

Dietary fiber is indigestible carbohydrate. Fiber is not used for energy by the body and so the grams of fiber are often listed separately under the carbohydrate category on nutrition labels. While dietary fiber is not used for energy, it has a beneficial role in digestion and metabolism.

Carbohydrates are classified in different ways. The most exact way is by chemical structure, with sugars classified as monosaccharides and disaccharides and more complex carbohydrates as polysaccharides or oligosaccharides.

Other Meanings and Uses of Carb

The word carb also has come to have several other meanings:

  • A food that is high in carbohydrate (or a serving of such a food) is sometimes called a carb. This is often a starchy food such as potatoes, bread, or rice. In this context, the word is more or less a slang term, because other foods high in carbohydrate, such as sugar-sweetened beverages, are rarely called carbs. It's a good idea to avoid using the word carb to refer to a food because it can create confusion as to what carbohydrate actually is.
  • People on low-carb diets often use carb to mean a gram of carbohydrate. They will sometimes say, "This apple has 17 carbs in it," or even more commonly will speak of foods having "lots of carbs" or "not many carbs."
  • A gram of net carb (also called effective carbs and other terms) can also be abbreviated to carb, particularly by people following a low-carb way of eating. This means that grams of fiber and possibly other types of carbohydrate that do not affect blood sugar have been subtracted from the total amount of carbohydrate.

Good Carbs vs Bad Carbs

You will also hear the terms "good carbs" and "bad carbs" which can be confusing because there is no one way to categorize the two. Different writers use their own definitions. This usage is referring to actual foods as carbs, which is not a good practice.

Foods high in refined carbohydrate are included on most lists of dietary recommendations as ones that should be limited or avoided. These include grains which are no longer whole, added sugars, and processed foods).

In "Dietary Guidelines 2015-2020" the Office of Disease Prevention and Health Promotion recommends shifting to eat more vegetables, fruits, whole grains, and dairy to increase consumption of calcium and dietary fiber. They also recommend shifting away from added sugars in drinks, snacks, and sweets.

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Article Sources
  • Dietary Guidelines 2015–2020. Office of Disease Prevention and Health Promotion. https://health.gov/dietaryguidelines/2015/guidelines/chapter-2/a-closer-look-at-current-intakes-and-recommended-shifts/#food-groups