Are carbohydrates really that bad?

foods with a small sign that says carbohydrates

Carbohydrates tend to get a bad rap. Maybe someone advised you to reduce your carb intake by avoiding white foods such as potatoes, pastas and breads, or you may have heard about popular low-carb diets like the ketogenic (“keto”) diet. But what exactly are carbohydrates, and are they really that bad? Let’s get into the basics with some frequently asked questions.

What are carbohydrates?

Carbohydrates are naturally occurring components of food. Along with protein and fat, they’re one of the three macronutrients in your diet — nutrients that your body needs a lot of to work properly. (“Macro” means “large-scale.”) When carbohydrates are digested, they are broken down into glucose, a simple sugar, and used to fuel all the cells in your body.

When you think of carbohydrates, you may immediately picture cookies and cake or potatoes, but carbohydrates are found in a variety of foods, including grains, fruits, vegetables, legumes and dairy.

What are the different types of carbohydrates?

There are three main categories of carbohydrates: sugars, starches and fibers.

Sugars are the most basic form of carbohydrates. Simple sugars are one or two sugar units (such as glucose, fructose and galactose). They often taste sweet and are found in fruits, juices, honey, milk and sweets, such as candy.

Starches are made up of many sugar units. You may hear these referred to as “complex carbohydrates.” Starch is found in vegetables, grains and legumes.

Fiber is a type of carbohydrate that the body cannot digest. Fiber is beneficial for cardiovascular and digestive health and helps you feel fuller longer, which may help with weight management. Fiber is found in whole grains, fruits and vegetables, beans, nuts and seeds.

How many carbohydrates do you need?

The Dietary Guidelines for Americans recommend that carbohydrates provide 45-65% of your daily calories. This means that about half of everything you eat should be carbohydrates.

Why do so many weight-loss diets promote low carbohydrate intake?

Low-carb diets, from Atkins to keto and everything in between, may help with an initial weight loss for a couple of reasons.

The first is water weight. The body stores extra carbohydrates with water. Often when people first start a low-carb diet, they may see a quick initial weight loss, but most often that’s due to water loss, not fat loss.

The next reason is that by cutting out carbohydrates, people are often cutting out indulgences, such as sweets and sugary beverages, which often leads to taking in fewer calories overall. These types of refined carbohydrates can also leave you feeling hungry shortly after you eat them, whereas carbohydrates from whole foods that include fiber — such as whole grains, veggies, beans and lentils — can help you feel fuller longer.

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However, while these diets may seem to provide a “quick fix,” it’s hard to stick with any type of restrictive eating. Research does not show that low-carb diets help you lose weight in the long term. In fact, many diets that have been shown to be healthful patterns of eating, such as vegetarian diets and the Mediterranean diet, are not low in carbohydrates. 

It’s also important to consider the types of foods you’re using to replace the carbohydrates in your diet. Those replacements are going to come from protein and fat. Too much saturated fat in the diet can lead to increased risk of cardiovascular disease.

In addition, when you cut entire food groups out of your diet, you may run the risk of coming up short on important nutrients, such as certain vitamins and minerals or fiber.

What if I have diabetes?

Peg Meissner, MS, RD, CDN, CDE, Clinical Dietitian, walks you through counting carbs if you have diabetes.

If you have been diagnosed with diabetes, you may need to pay special attention to your carbohydrate intake, although you do not need to cut out carbs entirely. This video will introduce you to carb-counting for a diabetic diet.

Overall, when it comes to health and weight management, instead of focusing on the amount of carbohydrates — or any other single nutrient or food group — it’s best to look at your overall pattern of eating. Here’s the perfect recipe from the American Institute for Cancer Research: a diet rich in vegetables, fruits, whole grains and legumes, with limited red and processed meats and sugary beverages.