Carbohydrates: From a Dietary Perspective

The body receives energy from three sources: fats, carbohydrates, and protein; each of these energy sources is important to ensure proper nutrition.  Carbohydrates continue to be a controversial topic as many people argue about the role they play in diabetes and obesity.  Contrary to popular "fad" diets that ban the consumption of this essential energy source, carbohydrates should consist of 40-60 percent of total calories. 

What are carbohydrates?

Carbohydrates "contain the sun's radiant energy, captured in a form that living things can use to drive the process of life" (Sizer & Whitney, 2012, p. 107).  Green plants make carbohydrates during the process of photosynthesis when sunlight is captured with chlorophyll to turn carbon dioxide and water into the most common sugar form, glucose (Sizer & Whitney, 2012).  With this in mind, carbohydrate rich foods come almost exclusively from plants, with the exception of milk derived from animals (Sizer & Whitney, 2012). 

How the body uses carbohydrates

In addition to fats and proteins, carbohydrates is the primary source for energy for the needs of the body.  The glucose in carbohydrates is essential for the brain and nervous system, and foods that are rich in fiber support digestion and nutrient absorption (Sizer & Whitney, 2012).  Individuals that have a diet that has large amounts of complex carbohydrates, derived from vegetables, legumes, and whole grains, have a reduced risk of heart disease and stroke because these diets are generally low on saturated fat, trans fat, and cholesterol (Sizer & Whitney, 2012). 

The importance of fiber

Currently, "there is much dispute over the components of dietary fiber, and there is not currently a single, worldwide definition for dietary fiber" (Lunn & Buttriss, 2007).  Fiber typically describes the non-digestible components of plants that make up the plant cell wall (Lunn & Buttriss, 2007).   Fiber reduces cholesterol in the digestive process by binding together and being excreted from the body.  High-fiber foods, such as whole grains, strongly reduce the risk of type 2 diabetes by maintaining the glucose in blood (Sizer & Whitney, 2012).  Fiber is very important in ensuring that the digestive system functions properly, and helps maintain colon health by reducing the risk of colon cancer (Sizer & Whitney, 2012).  Foods that are rich in fiber also tend to be low in fat, therefore a diet that is full of fiber-rich foods can help maintain or lower body weight.   

References:

Lunn, J., & Buttriss, J. (2007). Carbohydrates and dietary fibre. Nutrition Bulletin, 32(1), 21-64.

 

Sizer, F. & Whitney, E. (2012).  Nutrition: Concepts and Controversies, MyPlate Update (12th ed.).  Mason, OH: Cengage Learning.