Carbohydrates are our primary source of energy. They alone provide energy for red blood cells, and certain cells of the kidneys, and they’re the preferred fuel for the central nervous system, including the brain. Fat, on the other hand, is a secondary source of energy that can be used by some tissues, such as muscle, but is more often stored for use in times of famine.
Humans were designed by nature to crave carbohydrates. With their unique combination of sweet flavor, energy and nutrition, carbohydrates regulate our hunger drive. There are no carbohydrates in red meat, poultry, fish, shellfish, or eggs, and most dairy products contain little if any. Cheese, for example, contains only two percent. This is an important reason why people who eat a diet rich in animal foods rarely feel satisfied and become compulsive overeaters. Unless you eat enough carbohydrate foods, you’ll remain hungry and crave more food.
Unprocessed plant foods like brown rice, potatoes, squash, broccoli, and apples (just to name a few) are loaded with complex carbohydrates – long chains of sugars that must be broken down inside your intestine before they can be used as fuel. The process of digesting these complex carbohydrates is slow and methodical, providing a steady stream of fuel pumped into your bloodstream as long-lasting energy. On the McDougall diet, 70% – 90% percent of your calories are derived from complex carbohydrates, providing you with all the nutrients you need for optimum health, plus a high level of vitality and endurance.