What Do All Carbohydrates Have in Common?

Carbohydrates, also called carbs, serve as the main source of energy for your body. During the process of digestion, your body breaks carbohydrates down into simple sugars it can absorb. Carbohydrates are classified into three groups – starch, sugar and fiber – based on their structure. Your body uses the various types of carbohydrates differently, but all carbohydrates share common characteristics.

Molecular Structure

• All carbohydrates contain carbon (C), hydrogen (H) and oxygen (O) molecules linked together with the general molecular formula CH2O. Carbon, the sixth most abundant element on earth, is essential for life, and scientists devote an entire field of study, called organic chemistry, to the study of carbon compounds like carbohydrates. The H2O portion of the formula may make you think of water, but in carbohydrates the hydrogen molecules bind directly to the carbon atom forming a saccharide molecule.

Saccharides

• Carbohydrates are also called saccharides or sugar chains. The term saccharide comes from the Greek word sakchar, which means sweetness. Carbohydrates contain monosaccharides, disaccharides and polysaccharides. Monosaccharides are single-sugar molecules, such as glucose, fructose and galactose. Monosaccharides bind together to form disaccharides, which means two sugars. The carbohydrate in milk contains the disaccharide lactose which forms when glucose binds to galactose. Table sugar is a disaccharide called sucrose made when two glucose molecules bind together. Starch, found in vegetables like potatoes, contains long chains of saccharides called polysaccharides.

Digestion

• Your body breaks down carbohydrates, with the exception of fiber, into their most simple form so that cells lining the small intestines can absorb them for energy. Enzymes in the mouth, stomach and intestines break the long starch chains and disaccharides into the small monosaccharides. Once absorbed, you body converts the simple sugars into glucose that your cells and brain need to function.

Utilization

• Although all carbohydrates provide four calories per gram, your body does not utilize the energy in exactly the same way. Your body breaks down refined carbohydrates, like white rice, white bread and processed foods with added sugars, faster than complex carbohydrates found in natural foods like whole grains, fruits and vegetables. This is important to remember when choosing your meals. Eating processed, refined foods will give you a quick burst of energy, while eating natural foods gives you energy for longer periods of time, which will keep you feeling satisfied so that you eat less throughout the day.