Family Food & Nutrition FN 230

Carbohydrates, also referred to as "energy foods," are one of three calorie-containing nutrients found in foods. The other two nutrients are proteins and fats. Carbohydrates contain 4 calories per gram, as does protein. Fat is more calorie-dense, containing 9 calories per gram.

Carbohydrates are eventually metabolized by the body into blood glucose. All cells of the body utilize glucose as the primary energy source, particularly in the brain, for which glucose provides the only source of fuel. If carbohydrates are eaten in excessive amounts, just as if any nutrient is eaten to excess, the body converts the extra blood glucose into triglycerides for storage in adipose or fat cells, leading to weight gain.

Three specific types of carbohydrate are present in the foods we eat: starch, sugar and fiber.

Starch, also known as complex carbohydrate or polysaccharide, is present in foods such as cereals, whole grains, rice, pasta, potatoes, peas, corn and legumes.

Sugar has a more simple chemical structure than starch and is found naturally in many foods. Food sources of natural sugar include fruit, vegetables, milk and yogurt. Sugar is also commonly added to many foods in the form of white table sugar (sucrose), honey, corn syrup or fructose. Foods containing natural sugars are generally very nutritious, providing many vitamins, minerals, phytochemicals (natural plant chemicals) and antioxidants. These foods also tend to be good sources of fiber, such as that found in fruits, vegetables and whole grains. However, foods high in added sugars are often referred to as sources of "empty calories," meaning they add calories to the diet but provide little benefit in terms of vitamins, minerals or fiber.

Fiber, also a carbohydrate, is found in foods of plant origin. Fiber benefits the body in numerous ways, as discussed in a subsequent question.

Q: How much carbohydrate should the average person consume per day?

Individuals vary and therefore can differ in terms of how much carbohydrate each optimally needs on a daily basis. For most people, an ideal amount of carbohydrate is at least one-half of the day's total calorie intake, or between 50% and 60% of our daily energy needs. Individuals with special needs or a chronic condition such as type 2 diabetes or insulin resistance might benefit from a more individualized plan with a lower carbohydrate recommendation. The National Academy of Sciences recommends keeping carbohydrate intake above 130 grams per day, the minimum amount of glucose utilized by the brain.

In choosing carbohydrate-rich foods, it's best to include a wide variety of foods containing starch and natural sugar, such as whole grains, cereals, legumes, fruits, vegetables and dairy products. Special attention should be given to choosing foods high in fiber and reducing intake of foods with added sugars.