Carbohydrates: Choosing the Best Sources

Low-carb and ketogenic diets are all the rage these days. As a result, carbohydrates have become one of the most controversial nutrients on the planet. Yet, despite being vilified, carbohydrates are one of three critical macronutrients that support good health and give us the ability to function at our best. (20)

Maybe it’s time to stop putting carbs in the corner.

What are carbohydrates?

Carbohydrates are important for human health. First and foremost, they provide the energy your brain and body needs to function. Here’s how it works: your body breaks down the carbohydrates in the foods you eat into glucose (blood sugar). This provides a source of energy to your cells, tissues, and organs. Any glucose that isn’t immediately used is stored as glycogen in the liver and muscle for later use. (6)

But providing energy isn’t their only function. Carbohydrates help support a healthy microbiome and control blood sugar and insulin levels. (20) Consuming certain sources of carbohydrates can also foster better cardiovascular health by playing a beneficial role in cholesterol and triglyceride metabolism. (25)

While most foods contain a range of macronutrients (carbohydrates, fat, and protein), the foods we think of as “carbs” are predominantly made up of carbohydrates.

Did you know? Carbohydrate molecules are made up of carbon, hydrogen, and oxygen atoms, and they are the most abundant biomolecules (a molecule produced by a living organism) on Earth. (20)

Types of carbohydrates

There are two types of carbohydrates—simple and complex. What sets them apart from one another is the number of sugar molecules they contain.

Simple carbohydrates

Simple carbohydrates contain one or two sugar molecules which are combined in a simple chemical structure. (20) Because of their simple structure, they are broken down quickly by the body, providing a fast source of energy. (32) However, this can also lead to blood sugar spikes and crashes that propel hunger. (18)

Simple carbohydrates are found in some healthy whole foods like fruits and milk products; however, these carbohydrates are often the basis for many highly refined and ultra-processed foods too. These include white bread, cookies, candies, and sodas—foods typically low in fiber, high in added sugar, and lacking in important nutrients. (6) As a result of the impact simple carbs have on blood sugar, they have a high ranking on a scale called the “glycemic index.” The glycemic index ranks food from 0 to 100 based on how much a particular food raises your blood sugar levels two hours after you’ve eaten it. The higher the score, the higher it raises your blood sugar. (37) For instance, 100 g of white bread has a value of 73, while 100 g of broccoli has a value of 15. (1) This means that white bread will elevate your blood sugar much more than the same amount of broccoli.

Complex carbohydrates

Complex carbohydrates, on the other hand, are made up of three or more sugars arranged in a more complicated chemical structure. They are broken down more slowly by the body and have a more gradual impact on blood sugar levels. Complex carbohydrates also enhance the feelings of fullness. (20) This was shown in one study comparing a breakfast containing simple carbohydrates to one containing complex carbohydrates. The researchers found that the meal containing simple ones caused a sharp rise in blood sugar, insulin, and triglyceride levels compared to the complex carbohydrate breakfast. Those who consumed the breakfast with simple carbohydrates also reported feeling hungry and fatigued just 90 minutes after eating, while those eating the complex carbs had more energy and felt fuller longer. (27)

Complex carbohydrates can be found in beans, legumes, vegetables, whole grains, and some fruits. Not only do these foods provide a wealth of vitamins, minerals, and phytonutrients, they are also an excellent source of dietary fiber. Fiber not only helps keep you feeling fuller longer, it’s also been linked to a lower risk of some chronic health problems like heart disease and type 2 diabetes. (25)(24)(15)(2)

Did you know? Carbohydrates aren’t only found in food. They are also found in your blood, tears, and urine. (33)

Will carbohydrates make me fat?

As you might guess, whether carbohydrates contribute to weight gain all depends on the amount and type of carbohydrates you’re eating. Studies suggest that starting the day with a bowl of sugary cereal; grabbing a burger, fries, and soda for lunch; diving into a bowl of pasta for dinner; and topping the day off with a pint of Ben & Jerry’s will set you up for weight gain. (35)(23) This is because a diet filled with refined or ultra-processed foods provides a wealth of empty calories bereft of nutrients and fiber. What’s more, these highly processed simple carbohydrates increase hunger and food cravings that further fuel weight gain. (12)(29) If, however, you fill up on fiber- and nutrient-rich complex carbohydrates, studies suggest that you’re more likely to lose weight and keep it off. (16)

Did you know?
All carbohydrates, regardless of whether they are simple or complex, provide just four calories per gram. (21)

Best carbohydrates for good health

Fortunately, choosing which carbohydrates to include in your diet isn’t rocket science. A good rule of thumb is to opt for whole foods rich in vitamins, minerals, and fiber. Not only will these foods support good health, they can also help you maintain a healthy weight. Processed foods— especially ultra-processed foods like soda, chips, or sweetened cereal—typically provide empty calories from refined grains and sugar that contribute to weight gain and an array of health problems ranging from cardiovascular disease to diabetes to depression. (7) Here’s a cheat sheet to help you get started when choosing which carbohydrates you should add to your shopping cart and which to avoid.

What is the recommended intake of carbohydrates?

Choosing healthy carbohydrates instead of highly refined and processed ones is a good first step. But it’s also important to be mindful of your portions. After all, you can get too much of a good thing, even when eating the healthiest of carbohydrates. Excess carbohydrate intake can lead to weight gain. How much is enough? Dietary guidelines suggest that adult diets should be composed of 45 to 65% carbohydrate. That translates to about 200 g (¾ cup) to 300 g (1.2 cups) per day. (20)

It’s also important to focus on the amount of fiber in the carbohydrates you choose. According to the Academy of Nutrition and Dietetics, women should consume a minimum of 25 g of fiber daily and men should aim for 38 g. (9)

The bottom line

Carbohydrates are an essential macronutrient critical for good health. They provide us with the energy we need to function, help regulate blood sugar and insulin levels, and support a healthy gut and cardiovascular system. But not all carbohydrates are good for you. From chips to cookies and all the junk food in between, some highly refined and processed carbohydrates just provide empty calories and foster weight gain. On the flip side, complex carbohydrates provide many nutrients and fiber needed for optimal health. Moderate daily intake of healthy carbohydrates also supports satiety and a healthy weight.