Carbohydrates—An Ideal Source of Energy
The primary function of dietary carbohydrate is to supply energy to body cells.
Some cells, such as those in the brain, nervous system, and blood, use only carbohydrates for fuel
During high-intensity exercise, muscles get most of their energy from carbohydrates
During digestion, carbohydrates are broken into single sugar molecules such as glucose for absorption; the liver and muscles take up glucose and store it in the form of glycogen


Simple and Complex Carbohydrates
Simple carbohydrates contain one or two sugar units in each molecule
Found naturally in fruits and milk and added to many other foods
Include sucrose, fructose, maltose, and lactose

Complex carbohydrates consist of chains of many sugar molecules
Found in plants, especially grains, legumes, and tubers
Include starches and most types of dietary fiber

Whole Grains
Before they are processed, all grains are whole grains consisting of an inner layer of germ, a middle layer called the endosperm, and an outer layer of bran
During processing, the germ and bran are often removed, leaving just the starchy endosperm
Refined carbohydrates usually retain all the calories of a whole grain but lose many of the nutrients
Refined Carbohydrates Versus Whole Grains
Whole grains are higher than refined carbohydrates in fiber, vitamins, minerals, and other beneficial compounds
Whole grains take longer to digest
Make people feel full sooner
Cause a slower rise in glucose levels
Choose foods that have a whole grain as the first item on the ingredient list on the food label
Whole wheat, whole rye, whole oats, oatmeal, whole-grain corn, brown rice, popcorn, barley, etc.

Recommended Carbohydrate Intake

Adequate daily intake of carbohydrate = 130 grams
Acceptable Macronutrient Distribution Range = 45–65% of total daily calories as carbohydrate
Limit on intake of added sugars
Food and Nutrition Board: 25% or less of total daily calories
World Health Organization: 10% or less of total daily calories