Nutrition: Carbohydrates Chapter 2
Carbohydrates: Fuel for You
What are Carbs?Carbohydrates are the most easily obtained and most readily digested fuel for the body. The primary function of these dietary nutrients is to provide energy, which the body needs not only for physical activity but for the regular and healthy operation of its systems and individual organs. Carbs are present in many foods, including dietary staples such as rice, milk, bread, fruits, and vegetables. READ MORE
The Big 3
There are three main categories of carbohydrates.
Sugars such as those responsible for the sweetness in fruit (fructose) and table sugar (sucrose) are called “simple sugars” or “simple carbohydrates.” Some simple sugars occur naturally in vegetables, milk, honey, and other unprocessed foods. Synthetic sweeteners such as corn syrup and high fructose are simple sugars as well.
Starch is the most common carbohydrate in our diet. Because it’s made from longer strands of sugar molecules bonded together, starch is sometimes called a “complex sugar” or “complex carbohydrate.” Rice, potatoes, and corn (maize) are all starches. Wheat, the main ingredient in breads and pasta, is also a starch.
Fiber is another complex carbohydrate. Unlike other carbohydrates, though, fiber cannot be broken down into sugar to be used as energy. It passes through the system essentially undigested. Though fiber is not a nutrient, it aids digestion, helps the body manage its use of sugar, and regulates the sensation of hunger. Whole grains, legumes, and oats are all rich sources of fiber.
Carbohydrates are made up of carbon, hydrogen, and oxygen. If you look at the most simple chemical formula for a carbohydrate, it’s C1H2O1. Do you see the familiar H2O within the formula? That’s water. Carbohydrate means “hydrated carbon” — a carbon molecule attached to a water molecule. Though carbohydrate is actually a chemical compound found in food, we often refer to the food itself — pasta, potatoes — as a carbohydrate, or carb, when it’s a rich source. LESS
The Power ProcessRather than delivering energy directly, carbohydrates are converted into sugar once they’re consumed. Amylase, an enzyme in the digestive system, helps break the carbohydrates down into molecules of glucose (blood sugar). These molecules are small enough to pass through the intestinal wall and into the bloodstream. READ MORE
In biological terms, energy is measured in calories. There are 4 calories produced by each gram of carbohydrate. The number of calories describes how much energy a food source contains when that food is “burned” or metabolized by the body. Unused calories from any source can lead to weight gain. LESS
A Lightning Rod for Diet PlansSome of the most popular diet programs around have made carbohydrates out to be Waistline Enemy #1. Limiting your intake of high-calorie junk food is certainly good advice but severely restricting all carbs deprives the body of an important source for energy and a component used in muscle building, insulin stabilization, and other vital processes. READ MORE
As you learn more about carbohydrates in this health center, you’ll be better equipped to parse out the facts and farces that various anti-carb diets advertise. Meantime, here are two important misconceptions to recognize:
1. Carbs make you fat.
Wrong. Carbohydrates are neither solely nor directly responsible for weight gain. Some carbohydrates, especially in the form of refined foods and sweets, are high in calories without providing much (if any) nutrient value. But even a meal of “empty” calories can be burned off with exercise. When you consume more calories than you burn, you gain weight.
2. The body doesn’t need carbohydrates.
Wrong. Some popular diet plans implicitly suggest that we do not need to consume carbohydrates. But the body needs carbs badly enough that if you strike them from your meals, it finds another way. Your system will change protein into carbohydrate by converting dietary protein or by breaking down muscle.
Good Vs. Bad
In the realm of food science, there really is no such thing as a good carb or a bad carb. These are catch phrases coined by the authors of diet books. To indulge the vernacular here, “good” carbs occur organically and are packaged up by nature with other important nutrients. “Bad” carbs, occurring in food products that have been refined and/or processed, start out as good carbs but have been stripped of other valuable nutrients. With a balanced diet and regular exercise, the good vs. bad debate can nearly be dispensed altogether. LESS
theVisualMD Wishes to Thank our Scientific Collaborators:
- Julie M. Jones, PhD, CNS., LN.
College of St. Catherine
- David L. Katz, MD, MPH, FACPM, FACP
Yale University School of Medicine
- Mark Liponis, MDCanyon Ranch
- Molly Morgan, RD, CDN, CSSD
Nutritionist, Creative Nutrition Solutions
- Michael Stein, MD
- Chrissy Wellington, MS
Nutritionist, Canyon Ranch
The material on this site is for informational purposes only and is not intended as medical advice. It should not be used to diagnose or treat any medical condition. Consult a licensed medical professional for the diagnosis and treatment of all medical conditions and before starting a new diet or exercise program. If you have a medical emergency, call 911 immediately.