Nutrition Facts: What are Carbohydrates?

Components of Food A steak is a steak and a salad is a salad, but when you break down the simplest of foods, it really becomes quite complex. A leaf of lettuce is made up of fiber, water, and carbohydrates. Steak is composed of fat, protein, minerals, and vitamins. When you eat food, your body breaks it down into its simplest units. To understand nutrition, what your body needs, and how to stay within a healthy weight, it helps to understand what your food is made of.

Carbohydrates provide four calories per gram, and the current recommendation for the general population is that this category of food should make up between 45-65% of your daily caloric intake. Carbohydrates are the easiest food source for the body to convert into its preferred fuel, glucose (or blood sugar). Carbohydrates can be simple, table sugar and orange juice, or complex, like whole wheat flour.

Chemical structure

Saying a carbohydrate is complex refers to its chemical structure. All carbohydrates are strings of carbon, hydrogen, and oxygen linked together. At the heart of every carbohydrate molecule is a sugar. If it contains only a single sugar, its called a monosaccharide, or two sugars, is called a disaccharide, the molecule is considered a simple sugar, and it will have a sweet taste. Your body can digest simple sugars very quickly, and these are the molecules that have the fastest effect on blood sugar levels. Simple sugars include table sugar, grapes, and bananas.

A polysaccharide has multiple sugars at its heart. These are found in beans and whole grains. Your body has to work harder to break a polysaccharide down into usable sugar, so these molecules have a slower effect on blood sugar levels.

Function

The body converts carbohydrates into glucose, the body's preferred source of energy. Carbohydrates are essential in fueling the brain and the nervous system.

A single gram of carbohydrate provides four calories. So if you read a food label that says one serving of cookies contains 20 grams of carbohydrate, then that food item provides 4 calories x 20 grams, or 80 calories from carbohydrate.

What your body does with carbohydrates once you eat them depends on its immediate needs. If you are in the middle of playing an intense game of basketball, and you drink a sugary sports drink, your body will quickly convert those carbs into glucose and put some of them to work immediately, helping to fuel your muscles as you run up and down the court. What you don't use right away will circulate in your blood stream, ready to be used at a moment's notice. Once you stop playing the game, your body will use some of the remaining carbohydrates to fuel the process of repairing your body and getting it ready for the next bout of exercise. The body will store leftover glucose in the liver for a short period of time, just in case you need it.

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If you eat a slice of cake (also loaded with simple sugars) right before you go to bed, your body has no immediate need for the glucose that will be coursing through your bloodstream, so it will store this energy in the liver for a short time. Since you don't require large amounts of energy in your sleep, your body may convert some of this excess glucose into a more stable form for storage, unfortunately, this is when we convert glucose into fat for later use. Sources

Plants are the best source of carbohydrates. Plants use sunlight to make starches that they use for energy, and in turn, we eat the plants and are able to use that carbohydrate energy. In addition to starches and sugars, plants also produce cellulose, a third type of carbohydrate molecule that gives a lettuce leaf its structure or allows a corn stalk to stand up. Human bodies cannot digest cellulose, but it still serves an important function; the types of cellulose we can eat act as dietary fiber, helping to give bulk to stools, and keeping the walls of the digestive system scrubbed clean.

Simple carbohydrates

Simple carbohydrates (mono- and di-saccharides) have one or two sugar molecules at the base of their structure and they are very easy to break down into glucose. Mono means single, so monosaccharide is a single sugar; di means two, so disaccharide means double sugar. Fructose, or fruit sugar, and galactose, or milk sugar, are monosaccharides. Maltose, in beer, and sucrose, in table sugar, are disaccharides.

Strawberries, figs, apples, beer, milk, cheese, and candy all provide simple sugars.

Complex carbohydrates

Complex carbohydrates have multiple sugar molecules at their base, so it takes the body longer to convert them into glucose. Because of this, you feel fuller longer after eating a meal that contains lots of complex carbohydrates. Foods that have a lot of complex carbohydrates are also known as starches, like potatoes, beans, brown rice, and oatmeal.

"Good" versus "Bad" carbohydrates

Debate surrounds the values of carbohydrates and these innocent strands of carbon, water, and oxygen have acquired a very bad reputation in recent decades. Some diet plans, like the Atkins plan, ask participants to severely limit carbohydrate intake. On the other hand, the U.S. government's food guide pyramid still recommends getting most of your calories from carbohydrate sources. All the conflicting information can be very confusing, and the right answer really depends on your individual situation and needs. Some people have successfully lost weight and kept it off by limiting carbohydrates. Others just can't function without starches. It's not productive to think of carbohydrates as "bad," because your brain does need them to function. Instead of demonizing carbs, find ways to enjoy them as close to their natural form as possible.

A good rule of thumb is to choose food that has been refined as little as possible; eat an orange for dessert instead of orange cake. Sweeten your oatmeal with raisins instead of table sugar. Choose whole grains like brown rice over their refined equivalents whenever you have a choice. The more "whole" a food is, the less opportunity people have had to add refined sugars and additives to it. Unrefined sources of carbohydrate, like berries, oatmeal, bananas, and beans also provide minerals, vitamins, and dietary fiber that refined carbohydrates like white flour, sugar, sodas, and syrups do not.

Dietary fiber

Dietary fiber is the part of a plant that your body can't digest. Far from being waste material, fiber helps you feel full on fewer calories, which is really helpful if you're trying to manage your weight. Fiber can also help reduce the risk of bowel and heart disease.

There are two types of fiber, soluble and insoluble. Soluble fiber is the type that can dissolve in water, and when it does, it turns into a gel-like material that can help absorb cholesterol and move it out of the body. You can get soluble fiber from oats, peas, beans, apples, citrus, carrots, and barley. Insoluble fiber does not dissolve in water. It passes through your digestive system mostly unchanged, and as it goes, it scrapes the lining of the colon, helping to move out waste materials and dead cells. Insoluble fiber is very helpful for people who suffer from constipation and bowel irregularity. Whole wheat flour, wheat bran, nuts, and vegetables are good sources of insoluble fiber.

Doctors may ask some patients to take a concentrated powder form of fiber for specific reasons. Unless your doctor specifically advises you to use concentrated fiber, it is best to get your fiber from a wide variety of fresh fruits, vegetables, grains, and nuts. That way you can get their beneficial nutrients along with the fiber. Always drink plenty of water when you increase your fiber intake; water makes everything move more smoothly through your system. And if you want to increase your fiber intake, that's great, but do it slowly. Don't try to go from a diet of totally processed, refined foods to a "twigs and berries" diet overnight. Instead, gradually increase your intake of fruits and veggies over a couple of weeks to avoid stomach upset, gas, and bloating.

A word about artificial sweeteners

Artificial sweeteners are very different from natural sugars like sucrose and fructose. The chemical structure is different, and when you eat them, your body usually can't use these components for nutrients, so they don't contribute any calories to your daily intake. That does not mean, however, that they have no impact.

Sucralose (Splenda), Aspartame (Equal), and Saccharin (Sweet and Low) have all been studied and approved by the FDA. However, many people have concerns about these compounds. The body breaks down artificial sweeteners into smaller components. Aspartame breaks into aspartate, phenylalanine, and methanol. Some people can't process phenylalanine; it could cause brain damage, so the product has to be labeled for safety. Methanol also breaks down into formaldehyde and formates.

Many people use artificial sweeteners because they have diabetes and they want to avoid the blood sugar impact of eating too many simple carbohydrates, or they are trying to control their body weight. However, artificial sweeteners are usually found in less-than-ideal foods, diet soda, sugar free pudding, and so on. For a healthier alternative, try adjusting to unsweetened beverages and fresh fruit for dessert.