Carbohydrates in Your Diet

How many carbs you need depends on the nutrients you replace carbs with

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Carbohydrates are a component of food that supplies energy (calories) to the body. Carbohydrates are one of the three macronutrients, along with proteins and fats that our body uses to survive. Most foods contain some of each of these macronutrients in different proportions.

Examples of foods which contain mostly carbohydrates include grains, fruits, cereals, pasta, breads, and pastries.

Types of Carbohydrates

1. Sugars (also called simple carbohydrates): These are either simply molecules of simple sugars such as glucose, fructose, or galactose (monosaccharides) or two of these molecules joined together (disaccharides).

  Examples of disaccharides are table sugar which is made up of molecules of glucose and fructose joined together, and lactose, which is glucose and galactose joined together.

2. Starches (also called complex carbohydrates): Starches (polysaccharides) are composed of long chains of glucose. Your body breaks down starches into glucose, some more rapidly than others.  A special starch, called resistant starch, may be especially valuable to us.

3. Fiber: Fiber essentially means a carbohydrate such as the cellulose in plants which cannot be broken down for energy use in our bodies.

4. Oligosaccharides: There is also a fourth category between sugars and starches, called oligosaccharides, many of which have positive effects in our colons by being so-called prebiotics.

Do We Need Carbohydrates to Be Healthy?

The primary use of carbohydrates in the body is energy, but carbohydrates are not the only dietary source of energy.

Fats can also be used for energy, and are the main way our body stores energy. According to the Institute of Medicine's Dietary Reference guide, you can live without eating any carbs as long as you eat adequate amounts of protein and fat:

"The lower limit of dietary carbohydrate compatible with life apparently is zero, provided that adequate amounts of protein and fat are consumed."

Our bodies can actually make the amount of glucose we need to survive (the Institute of Medicine estimated this to be about 22 to 28 grams per day) in a process called gluconeogenesis—synthesizing glucose primarily from proteins.

Carbohydrates and Low-Carb Diets

Many low-carb diets recommend removing processed sources of carbohydrates. Some diets like the Atkins diet or South Beach diet have specially formulated protein bars that are low-carb. While other low-carb diets like the Paleo diet and ketogenic diet recommend eliminating processed carbs like bread and dairy and also limiting fruit. If you are counting carbs, make sure you read the nutritional labels of the foods you are eating. The carb counts of processed foods can vary from brand to brand, especially when it comes to sweetened versus unsweetened versions of foods. 

Before you eliminate all carbohydrates from your diet, it is important to know that foods containing carbohydrates also contain other important nutrients. If you respond well to lower-carb diets or are following them for weight loss or other health reasons, you can swap carb-rich foods for vegetables and fruits high in vitamins, minerals, fiber, and phytonutrients.

With some attention and reading food labels, you can eat a healthy diet that has fewer carbohydrates than the sugary and starchy diet often consumed by people today. 


Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients) (2005), Institute of Medicine, Food and Nutrition Board, National Academy of Sciences.