Carbs are highly controversial these days.
The dietary guidelines suggest that we get about half of our calories from carbohydrates.
On the other hand, some claim that carbs cause obesity and type 2 diabetes, and that most people should be avoiding them.
There are good arguments on both sides, and it appears that carbohydrate requirements depend largely on the individual.
Some people do better with a lower carb intake, while others do just fine eating plenty of carbs.
This article takes a detailed look at carbs, their health effects and how you can make the right choices.
What Are Carbs?
Carbs, or carbohydrates, are molecules that have carbon, hydrogen and oxygen atoms.
In nutrition, “carbs” refers to one of the three macronutrients. The other two are protein and fat.
Dietary carbohydrates can be split into three main categories:
Sugars: Sweet, short-chain carbohydrates found in foods. Examples are glucose, fructose, galactose and sucrose.
Starches: Long chains of glucose molecules, which eventually get broken down into glucose in the digestive system.
Fiber: Humans can not digest fiber, although the bacteria in the digestive system can make use of some of them.
The main purpose of carbohydrates in the diet is to provide energy. Most carbs get broken down or transformed into glucose, which can be used as energy. Carbs can also be turned into fat (stored energy) for later use.
Fiber is an exception. It does not provide energy directly, but it does feed the friendly bacteria in the digestive system. These bacteria can use the fiber to produce fatty acids that some of our cells can use as energy.
Sugar alcohols are also classified as carbohydrates. They taste sweet, but usually don’t provide many calories.
Carbohydrates are one of the three macronutrients. The main types of dietary carbohydrates are sugars, starches and fiber.
“Whole” vs “Refined” Carbs
Not all carbs are created equal.
There are many different types of carbohydrate-containing foods, and they vary greatly in their health effects.
Although carbs are often referred to as “simple” vs “complex,” I personally find “whole” vs “refined” to make more sense.
Whole carbs are unprocessed and contain the fiber found naturally in the food, while refined carbs have been processed and had the natural fiber stripped out.
Examples of whole carbs include vegetables, whole fruit, legumes, potatoes and whole grains. These foods are generally healthy.
On the other hand, refined carbs include sugar-sweetened beverages, fruit juices, pastries, white bread, white pasta, white rice and others.
Numerous studies show that refined carbohydrate consumption is associated with health problems like obesity and type 2 diabetes (1, 2, 3).
They tend to cause major spikes in blood sugar levels, which leads to a subsequent crash that can trigger hunger and cravings for more high-carb foods (4, 5).
This is the “blood sugar roller coaster” that many people are familiar with.
Refined carbohydrate foods are usually also lacking in essential nutrients. In other words, they are “empty” calories.
The added sugars are another story altogether, they are the absolute worst carbohydrates and linked to all sorts of chronic diseases (6, 7, 8, 9).
However, it makes no sense to demonize all carbohydrate-containing foods because of the health effects of their processed counterparts.
Whole food sources of carbohydrates are loaded with nutrients and fiber, and don’t cause the same spikes and dips in blood sugar levels.
Hundreds of studies on high-fiber carbohydrates, including vegetables, fruits, legumes and whole grains show that eating them is linked to improved metabolic health and a lower risk of disease (10, 11, 12, 13, 14).