What is a Carbohydrate?
A carbohydrate is a compound with 1 or more sugars. The more complex the structure (the more sugars and the more branching) the more complex the carbohydrate. Simple carbohydrates are just that, simple. They have one or two sugars bound together. We call simple carbohydrates, simple sugars. Complex carbohydrates have many sugars linked together. This is the way we store sugar and the way plants store sugar and gain structure. CHO is a commonly used abbreviation for carbohydrate.
carb = carbon hydrate = water saccharide = sugar
mono = one or single di = two or double poly = many
carb = carbon hydrate = water saccharide = sugar
mono = one or single di = two or double poly = many
Simple Carbohydrates

Simple carbohydrates are simple sugars. There are 6 simple CHOs:
3 single sugars and 3 double sugars:
3 single sugars and 3 double sugars:
- Monosaccharides (single sugars)
- fructose: fruit sugar
- glucose: body’s blood sugar
- galactose: part of milk sugar
- Disaccharides (double sugars)
- maltose: glucose + glucose = malt sugar
- sucrose: fructose + glucose = table sugar
- lactose: galactose + glucose = milk sugar
Complex Carbohydrates

A complex carbohydrate is a polysaccharide. Poly means many and saccharide is sugar. In polysaccharides, the main sugar unit is glucose. Polysaccharides are made up of many glucose units, up to several thousand! There are 3 complex carbohydrates:
Starch
Glycogen
Fiber
Starch
- Plant storage form of carbohydrate
- Repeating units of glucose with some branching
- An example is the starch stored inside a corn kernel
Glycogen
- Animal storage form of glucose
- Repeating units of glucose, highly branched, very dense
- Glycogen is our (humans) storage form of carbohydrate
- There are very few carbohydrates in meat we eat (eg: chicken), because the glycogen breaks down rapidly once the animal is slaughtered.
Fiber
- Structural component in plants
- Repeating units of glucose linked together
- Bonds cannot be broken (digested) by humans
- Fiber passes through the digestive tract unabsorbed
- Cellulose, a type of fiber, makes up the cell wall of plants
Types of Foods with Carbohydrates
Most whole carbohydrate foods have both simple and complex carbohydrates. Grains have starch and fiber and a small amount of naturally occurring sugar. Fruits have naturally occurring glucose, fructose, sucrose and fiber. Some fruits, such as bananas, also have starch. Vegetables have a small amount of glucose, fructose, sucrose along with fiber. Green vegetables have little to no starch, while root vegetables such as potatoes and carrots have more starch. Dairy has lactose. Nuts have fiber and a small amount of sucrose and starch.
Simple vs Complex Carbohydrate Video
References
- Groff. J, Gropper S. Chapter 4 Carbohydrates. In: Advanced Nutrition and Human Metabolism 3rd Ed. Belmont, CA. Wadsworth; 2000.
- Carbohydrates. US National Library of Medicine. https://www.nlm.nih.gov/medlineplus/ency/article/002469.htm. Last updated February 2, 2016. Last accessed February 27, 2016.
- Monoaccharide and disaccharide diagram by Christine Dobrowolski, CC BY-SA 2.0.
- Starch, fiber and glycogen diagram by Christine Dobrowolski, CC BY-SA 2.0.
- Wheat header image by Charles Knowles on FlickrCC, CC by 2.0.
Last updated April 8, 2016.