What is the Function of Carbohydrates? Do I Need Them?

Carbohydrates: The boogeyman in just about every diet these days. It seems like everyone is up in arms trying to eliminate or reduce carbs from their diets, citing them as the reason for all their woes. So, what is the function of carbohydrates? Do you really need them? Are they as bad as everyone says? Contrary to what some diet salespeople might tell you, the answers are not so simple.

Carbohydrates are the most diverse class of macronutrient there is. How they are arranged, where they come from and what they do to differs wildly from carb to carb. As such, you can’t pin down carbohydrates as having a single effect on your body.

By understanding the uses of carbohydrates, the different kinds of carbs there are and how they react to your digestive system, you can make more informed decisions about the carbohydrates in your life. Don’t cut them out of your diet until you get the facts.

Carbohydrates: The Basics

What are carbohydrates used for? If there is one simple answer to this question, then it is this: energy. All carbohydrates are sugar, and sugar gives us energy. Now you may be thinking, “Bread is all carbs, but it isn’t sweet. What are you talking about?” True, carbs may not always come in the form of sugars, but when your body breaks them down to digest them, they get converted to sugars for your body to use as energy.

Technically speaking, carbohydrates are not an essential nutrient. This means that you do not need to eat them to survive because your body can make them. Carbohydrates energy is the same as fat and protein-energy, so you could survive off of the other two. However, it is difficult to lead a healthy and active life without them. They are not only a great source of long-term energy for physical activity but also are found in most staple foods all over the world.

How Many Calories are in Carbohydrates?

Again, since they are so diverse, there is no simple answer to this. Some carbs have more calories than others. Also, some carbs break down more quickly into energy than others. This fact is important to consider, because if your body does not immediately burn that sugar that it just got saddled with into energy, then that sugar is getting converted to fat and hanging around your belly for later use.

While you can’t pin down an exact number for the calories in carbs, it is safe to say that carbohydrates are generally calorically dense. This means that even small amounts of them can contain a relatively large number of calories. We’ll go over which carbs are most caloric and how your body breaks them down in each carb type section.

The Main Types of Carbohydrates

Seeing as how they are so different, it is important to get a handle on the important types of carbs that you eat. They come in two broad varieties: simple and complex. Within these categories are other types worth noting as well.

Simple Carbs

Simple carbs are sugars in their pure forms. The three types of sugars are glucose (also known as dextrose), fructose and galactose. Alone, they form monosaccharides and are the common sweet sugars you are used to, like table sugar and sweeteners. Link two of them together and you get the disaccharides such as lactose, maltose, and sucrose.

Simple carbs, while delicious, are the kind you want to avoid. The body does not need to much work to digest these simple sugars and shoot straight into your bloodstream. That’s what a sugar rush is; a quick shot of fuel that burns fast.

However, dumping sugar into your system is like throwing gas onto a fire; it burns hot and bright but it can be dangerous. The excess fire goes out of control, but the excess sugar in your system goes straight to your fatty cells if it isn’t used right away. Additionally, since simple carbs often have a high number of calories in them, you will be hard pressed to burn them all in time.

The Dangers of Too Much Sugar

Getting fat is no picnic, but that could be the least of your worries if you consume excess sugar regularly. When your blood sugar rises from consuming sugar, your pancreas sends out insulin to signal to your cells to absorb sugars for energy. Having high amounts of sugar in your system all the time lowers your system’s insulin sensitivity, meaning insulin has a lesser effect on your cells.

Your pancreas will pump out insulin, but your cells won’t listen, and your blood sugar stays spiked. This condition, as believed by many scientists, leads to metabolic syndrome, which is characterized by high blood pressure, bigger waists and clogged arteries; all of which are risk factors for serious health problems. As excess sugar consumption rises around the world, the number of metabolic syndrome cases has likewise increased.

Complex Carbs

If they are so dangerous, why not ditch them completely? Well, not all of them are so bad for you. What is the function of carbohydrates that are complex? Mostly, they are fantastic sources of energy, and they provide health benefits rather than risks if you eat the right kind in the right amounts.

Complex carbs consist of three or more sugar molecules linked together. They are classified as either oligosaccharides or polysaccharides. These are the carbs that usually do not take the form of sweet sugars, like starch and fiber. They do break down in your digestive tract into sugars, but how they break down determines their effects on your body as a whole.

Since complex carbs consist of so many sugar molecules bonded together, your digestive system needs time to break them down. Because of that, the sugars and thereby energy is released slowly over time. So instead of bouncing off the walls and jittering, you have a stable amount of energy throughout the day or a workout. Simple carbs are gas to the fire, and complex carbs are slow-burning wood.

The Risks of Complex Carbs

Carbs for energy is great, but there is a limit to this as well. Complex carbs do raise blood sugar more slowly than simple ones, but some complex carbs break down into sugars so quickly that too much of them can have a similar effect as simple carbs. Spiked blood sugar.

Starch, for example, is sugar molecules bonded together with alpha linkages. The links are easily sundered by the enzymes in your digestive system and those sugars flood your system giving you energy, but also higher blood sugar. Crackers and white bread made with refined flour have high amounts of starch in them and are not that much better for you than sugary foods. Too much of these foods can also lead to metabolic syndrome, but there is hope.


Fiber, which can be found in vegetables like broccoli, whole grains like wheat bread, and fruits like apples, is a complex carb unlike any other. The sugars present in fiber are bonded together with beta bonds. Your body cannot break these bonds down, but this is not a bad thing, it is actually quite beneficial.

Since your intestines can’t break it down completely, fiber remains in your digestive tract more or less intact. Therefore, fewer sugars get released into your system meaning more normal blood sugar levels and fewer calories. Also, fiber has the ability to neutralize other starches in your gut, so that they don’t release all of their sugars into your bloodstream. It effectively limits the amount of sugar your body can absorb, so you don’t overdo it.

Furthermore, fiber has an even wider array of health benefits. It expands in your gut and hangs around for a while because it doesn’t get broken down, which leads to you feeling fuller for longer. Besides killing cravings, fiber also makes your stool more solid which helps clear out waste and keeps your bowels healthy.

A Place for Carbs

Not all carbs are created equal. Asking, “What is the function of carbohydrates?” is a lot like asking “What is the function of electricity?” It can be used for a variety of functions, most of which involving energy. Too much of it directly into your system can be dangerous, but the correct type in the correct amount can be the key to a healthy and active life.

Humans can survive without carbs; they don’t serve a vital function. But humans can also live without electricity, though few of us would choose to do so. Carbohydrates can be a great source of long-term energy for people who exercise or just a great way to lose weight. For this complex (and also simple) macronutrients, it’s all in the execution.

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