Simple carbs contain one or two sugars. They are found in dairy products as galactose, as fructose in fruit (that also contain many valuable micronutrients); in high-fructose corn syrup, white flours, white rice, and in many refined and processed products. Double sugars such as maltose are in some vegetables, lactose in dairy, and sucrose in refined table sugar, syrups, and honey.
Complex carbs contain three or more sugars. Many vegetables are considered complex: beans, split peas, and lentils; mushrooms, spinach, onions, broccoli, peppers, and starchy vegetables; along with whole grains, including oatmeal, quinoa, barley, and brown rice. Complex carbohydrates provide calories as well as vitamins, minerals, enzymes, and other micronutrients.
Fiber (soluble and insoluble) that refers to carbohydrates the body cannot digest. Fiber is the indigestible portion of plants that pass through the intestinal tract intact and help to move waste out of the body. Fiber is not absorbed into the bloodstream and provides no calories. Legumes, nuts, seeds, the fibers in some fruits and vegetables, and ancient whole grains are rich sources of this type of carbohydrate.