Dietary Requirements of Carbohydrates

DIETARY REQUIREMENTS

Although there is no specific daily dietary requirement for carbohydrates, the Food and Nutrition Board of the National Research Council recommends that half of one’s energy requirement come from carbohydrates, preferably complex carbohy-drates. (The recommendation is 10% of energy to come from simple carbohydrates.) For example, assume that one’s total energy requirement is 2,000 calories. One-half of this is 1,000. Divide 1,000 calories by 4 (the number of calories in each gram of carbohydrate) for an estimated carbohydrate requirement of 250 g/day.

A mild deficiency of carbohydrates can result in weight loss and fatigue. A diet seriously deficient in carbohydrates could cause ketoacidosis, a stage in metabolism occurring when the liver has been depleted of stored glycogen and switches to a fasting mode. At this point, energy from fat is mobilized to the liver and used to synthesize glucose. The by-products of fat breakdown are ketones that build up in the bloodstream and are then released through the kidneys. To prevent these effects, one needs a minimum of 50–100 grams of carbohydrates each day.

The overweight population constitutes a major health problem in the United States. Some believe eating excess carbohydrates to be the most common cause of obesity. Although surplus carbohydrates are changed to glycogen, the major part of any surplus becomes adipose tissue. Also, an excess of carbo-hydrate in the form of sugar can spoil an appetite for other nutrients that are more important. Too many carbohydrates may cause tooth decay, irritate the lining of the stomach, or cause flatulence.