How Carbohydrates Support a Healthy Diet
By Monica Reinagel, MS, LDN, CNS
Although carbs often get a bum rap, some of the healthiest foods that you can eat, such as fruits and vegetables are primarily carbohydrate. Not only that but some of the foods that we think of as “carbs,” such as pasta or potatoes, also contain a substantial amount of protein!
Carbs are not the enemy when it comes to managing your weight. But various types of carbs affect your appetite and energy differently—and this can either help or hinder your weight management efforts. Let’s clear up some common carbohydrate confusion and take a look at how carbs fit into a healthy diet.
What Are Carbohydrates?
First things first: carbohydrates are one of three macronutrients that make up most of the food we eat. (The other two macronutrients are fat and protein.) Carbohydrates can further be broken down into three subcategories: sugars, starches and fiber. Each of these behaves differently in the body.
- Sugars (aka simple carbs) are small molecules that are rapidly absorbed into the bloodstream. You’ll find them in fruit and milk as well as in sweeteners like honey, maple syrup and table sugar.
- Starches (aka complex carbs) are larger molecules made up of hundreds (or even thousands!) of sugar molecules chained together. These take a bit longer to digest and absorb. You’ll find them in grains, legumes, potatoes and other starchy vegetables.
- Fiber is a type of carbohydrate that cannot be digested by humans—but does provide a valuable food source for the beneficial bacteria that live in our guts and help keep us healthy. Whole fruits, vegetables, legumes and grains all provide fiber.
Simple Carbohydrates vs Complex Carbohydrates
Two other terms that you’ll often see used in relationship to carbohydrates are refined and unrefined. These are sometimes confused with simple and complex but they are not at all the same thing.
The terms “simple” and “complex” refer to the size of the carbohydrate molecule, or whether we’re talking about a smaller sugar molecule or a larger starch molecule. The terms “refined” and “unrefined” have nothing to do with the size of the molecule; instead, they refer to the degree of processing.
- Simple carbohydrates (sugars) are found in both refined and unrefined forms. Table sugar and apple juice are examples of refined sugars. Maple syrup would be an example of an unrefined sugar. The natural sugars in fresh fruit are also unrefined.
- Complex carbohydrates (starches) are also found in both refined and unrefined forms. White bread, made from refined white flour, may be described as a refined carbohydrate but it still contains complex carbohydrates. Whole grains and starchy tubers, on the other hand, contain complex carbohydrates in their unrefined forms.
It’s worth pointing out that while the difference between simple and complex carbohydrates (i.e., sugars and starches) is fairly black and white, the distinction between refined and unrefined carbs is a little bit fuzzier. I like to think of it more like a spectrum. For example, whole wheat flour is more refined (or processed) than whole, intact grains, but less refined than white flour.
Which Types of Carbohydrates Are Best?
Now that we’ve got all the definitions out of the way, let’s talk about how different types of carbohydrates can help (or hinder) your nutrition and weight management goals.
When it comes to managing your appetite, energy levels, and calorie intake, unrefined carbohydrates from whole fruits, vegetables, legumes, and whole grains are the way to go. Not only do these unrefined carbs retain more nutrients than their more refined counterparts, but they generally also include more fiber—and that can help fill you up for fewer calories. A bowl of tabbouleh made with bulgur wheat (an unrefined complex carb) will probably keep you going for a lot longer than a bagel (a refined complex carb).
Of course, it is possible to overdo just about anything. Although whole grain foods are more nutritious than their refined counterparts, they are still a relatively concentrated source of calories. Don’t let the fact that it's whole grain seduce you into thinking that you don’t need to pay attention to portion size.
The fiber in unrefined carbohydrates also helps slow down the absorption of sugars from foods into your bloodstream. Steadier blood sugar means steadier energy (not to mention a lower risk of diabetes). Perhaps that’s why consumption of sugar-sweetened beverages (a refined simple carb) is associated with increased risk of diabetes while consumption of whole fruit (an unrefined simple carb) is associated with a decreased risk.
When it comes to the non-starchy vegetables, on the other hand, it’s hard to overdo it. Even though they contain mostly simple carbohydrates, they are relatively low in calories and bursting with nutrition.