Simple vs. Complex Carbohydrates

Carbohydrates are one of three primary macronutrients, in addition to protein and fat, that are found in our food. During the process of digestion, carbohydrates are broken down into sugar (glucose) which is used as a primary source of fuel for the body.

Scientifically speaking, carbohydrate molecules are made of oxygen, hydrogen, and carbon atoms, and are also known as saccharides, which means “sugar”. Depending on the number of saccharides present in the structure, carbohydrates are classified as mono- (1), di- (2), oligo- (3-20), or poly- (many) saccharides. Monosaccharides and disaccharides are considered simple carbohydrates, while oligosaccharides and polysaccharides are considered complex carbohydrates.

What are Simple Carbohydrates?

Simple carbohydrates, as the name implies, are simple structures since they contain one or two sugar molecules linked together. Monosaccharides are single sugar molecules and include glucose, fructose, and galactose and are the building blocks for other carbohydrates, while disaccharides are double sugar molecules and include sucrose, maltose, and lactose. Because simple carbohydrates are made up of shorter sugar chains, they are more quickly digested and absorbed by the body given they require less time to be broken down.

Simple carbohydrates can be identified by their sweet taste and are found in most processed foods including breakfast cereals, baked foods, and candy, and include any form of processed sugar. These forms of simple carbohydrates are highly processed, devoid of their own nutrients, and are best avoided, however, not all forms of simple carbohydrates are processed. In fact, simple carbohydrates can also be found in many whole foods including fruit, dairy, and some vegetables. The benefit of whole food sources of simple carbohydrates is that they come packed with fiber, vitamins, and minerals which help to slow the rate at which sugar is absorbed and provide nutritional value at the same time. On the contrary, processed foods made of refined carbohydrates and added sugars are devoid of fiber and nutrients and therefore the rate at which the sugar is absorbed is much greater.

What are Complex Carbohydrates?

Complex carbohydrates are made up of sugar molecules that are strung together in long, complex chains, also known as oligosaccharides and polysaccharides. Complex carbohydrates are made up of digestible, partly digestible, and indigestible starches, and for this reason, take longer for the body to break down and digest and allow for a more gradual release of energy. Whole grains, beans, lentils, and vegetables are all examples of foods that contain complex carbohydrates and, compared to simple carbohydrates, contain a much larger amount of fiber.

However, the format in which complex carbohydrates are consumed can greatly influence whether they remain an ideal choice or not. For instance, grains are a form of complex carbohydrates, but when milled into refined flour they become a form of simple carbohydrates given the fiber and nutrient-dense bran and germ are removed in the process. These forms of carbohydrates are often referred to as refined carbohydrates and include items such as cereals, bagels muffins, cookies, crackers, and pastries, just to name a few.

Simple vs. Complex Carbohydrates: Which is Better?

It is important to understand that all forms of carbohydrates are digested into monosaccharides, or simple sugars, before they’re absorbed by the body, regardless of whether the original source was a spoonful of sugar or a bowl of oatmeal.  Generally speaking, complex carbohydrates are digested at a slower rate than simple carbohydrates, given they contain a larger amount of fiber, however, that does not mean that all simple carbohydrates are a poor choice and all complex carbohydrates are a good choice. Simple carbohydrates are found in many whole foods, such as fruits and milk, and complex carbohydrates can be found in many refined foods, such as baked goods, making them a less-than-ideal choice.

So, instead of focusing solely on the type of carbohydrate, simple or complex, it is best to focus on the amount of fiber, vitamins, and mineral present, and whether the item in question is a whole food or not.

The Bottom Line

Both simple and complex carbohydrates can be consumed as part of a healthy diet when you focus on whole food such as fruits, vegetables, whole grains, beans, and lentils. These forms of carbohydrates are rich sources of fiber, vitamins, and minerals which will help to balance your blood sugar and support digestion while serving as a source of energy at the same time.