What Are Carbs and How Much Do You Need in Your Diet?
How much do you know about carbs? They’re one of the most debated topics when it comes to healthy eating. It seems everyone has an opinion on carbohydrates, from vegans and flexible dieters to keto and paleo enthusiasts — and every diet seems to prescribe a different “right” amount. Do you feel confident in choosing carbs, or do you wonder whether maybe you need to cut back (or add more)?
Read on to learn everything you should know about carbs (and a few things you should forget).
What Are Carbs?
Foods are made up of three different “macronutrients” carbohydrates is one, and the other two are fats and protein. Carbs (formally known as carbohydrates) are your body’s preferred energy source. Carbs are molecules made up of carbon, hydrogen, and oxygen, which we know as sugars, starches, and fiber, says Paige Benté, MS, RD, CSSD.
Almost all foods contain at least a small amount of carbs. Though it’s common to divide up and label foods as being a source of just one of the three macros, most contain two, if not all three, in varying amounts. For example:
- Beans — have both protein and carbs
- Nuts — have a good amount of all three macronutrients — protein, carbohydrates and fat.
“Carbohydrates are necessary for many functions in the body, but especially for brain functioning and blood sugar regulation, ” says Samantha Coogan, MS, RD, the director of the didactic program in nutrition and dietetics at the University of Nevada Las Vegas.
Carbs also play an important role in our workouts. We break down the sugars and starches in carbs into glucose, which we burn or store in our liver or muscles as glycogen. During exercise, we tap into those glycogen stores, which are “a reservoir when the body needs to utilize carbs for fuel,” explains Coogan. “Distance athletes will tap into it as the race duration increases, and power athletes, such as sprinters or power lifters, need adequate amounts of glycogen in order to produce enough force and power.”
Different Types of Carbs
There are many different types of carbs and the health value of the different types are extremely variable. There are two basic groups of carbs — complex and simple — and the difference between them is the structure of their molecules, which influences where and how they are digested.
Here’s a look at some of the different types of carbs, which will all eventually be broken down into glucose. (Heads-up: Some types of carbs go by more than one name!)
Complex carbs are larger molecules referred to as polysaccharides or oligosaccharides. They’re found in foods like grains, legumes, vegetables, and potatoes. They are starches and fibers (defined below), like the whole-grain bread in your sandwich or the brown rice next to your chicken at dinner. In general, you should incorporate complex varieties of carbs into your diet whenever possible.
“Starch is a more complex form of carbohydrate that requires more steps than simple carbs in metabolism,” says Coogan.
Starches contain both branched and linear molecules, so they take more energy to break down (and that means they take longer to digest) compared to simple carbs.
Sugars are carbs and they can be found everywhere from the lactose in milk to the high-fructose corn syrup in soda. “The biggest misconception is that carbs and sugar are different,” says Coogan. “Every carbohydrate will eventually break down to glucose regardless of where it started.”
Even though carbs and sugars both end up as sugar, and therefore are not ‘different,’ they take a different path to become a sugar, which is what differentiates them, along with the nutrients (or lack thereof) you’re receiving from the sugar or carb-containing food.
There are two main types of fiber: soluble and insoluble.
- Soluble fiber is the type of fiber predominately found in oatmeal, nuts and seeds, pulses, fruit and vegetables. Soluble fiber absorbs and dissolves in water, which creates a gel-like consistency. Research suggests that foods containing fiber, specifically soluble fiber have the potential to benefit overall heart health.
- Insoluble fiber is typically found in whole grains, vegetables and the skin of fruits. Unlike soluble fiber, insoluble fiber does not dissolve in water but rather adds bulk to your stool, aiding in healthy digestion.
Fiber is found in carbohydrate foods and for the most part, is not digested. A small amount of fiber however, is fermented by the bacteria in your gut which creates beneficial short chain fatty acids.
Simple carbs are a type of carbohydrate with one or two sugar molecules, known as mono- or disaccharides, respectively. They only contain linear molecules, so they’re easier to break down than complex ones (starches) and are digested more quickly, says Coogan. Some examples of natural simple carbs include the fructose in a piece of fruit, or the lactose in a glass of milk.
Beyond those natural sources, simple carbs can also be present in refined and processed foods as added sugars — meaning they do not occur naturally but are added to the food or beverage to sweeten them. Some examples include:
- Regular sodas,
- fruit-flavored drinks,
- energy drinks,
- and pastries and donuts.
All of which you generally want to avoid.
“Natural” sweeteners like honey, agave nectar, or maple syrup also count as added sugars. But all simple carbs, even added sugars, can have their place in a healthy balanced diet. (So let’s stop calling them “bad” carbs!)
“It’s important that athletes have very quickly digestible sources of carbohydrates, and those are frequently highly refined carbs or simple sugars,” says Benté. This is why, she says, athletes consume goos, chews, and gummy bears before, during, or after a race — they’re full of simple sugars that their muscles can rapidly convert into energy.
The term “refined” means that “carbs have gone through further processing” compared to whole, unrefined foods, says Coogan. They usually have a lower nutrient density, as nutrients (including fiber) are stripped out during the refinement process, she adds.
Complex carbs can become refined carbs, through processing. Some examples are white bread, white rice, and pasta, which all come from whole grains that were processed to remove the tough outer shell (along with most of the fiber and other nutrients). Even removing the skin from sweet potato or squash before eating is technically a refinement, as it strips out some of the fiber.
Healthy Sources of Carbohydrates
Now that you know the difference between types of carbs, here are a few convenient lists of healthy sources of carbohydrates.
- Brussels sprouts
- Collard greens
- Squash (summer)
- String beans
- Honeydew melon
- Salsa (pico de gallo)
- Tomato sauce (plain, no sugar added)
- Brown rice
- English muffin (whole grain)
- Oatmeal (steel-cut or rolled)
- Pancakes (whole grain)
- Pasta (whole grain)
- Pita (whole grain)
- Refried beans (nonfat)
- Sweet potato
- Wild rice
Daily Carbohydrate Intake
Now, let’s look at how many carbs you need daily. The 2015-2020 Dietary Guidelines for Americans recommend that carbohydrates make up 45 to 65 percent of our daily calorie intake. Carbohydrates provide four calories per gram, so if you eat 1,500 calories a day, that would be about 169 to 244 grams of carbs.
Your body needs carbs to function. While overdoing it on carbs is more common, consuming too few carbs “can be detrimental,” says Coogan. The current recommended intake of carbohydrates for the average healthy adult is at least 130 grams per day, the minimum amount necessary to feed the brain, however, certain health conditions, including diabetes and obesity can alter these recommendations. For reference, a medium sweet potato contains 30 grams of carbs (and almost 5 grams of fiber).
Beyond that, carbohydrate needs can vary significantly, depending on health, exercise goals, age, and sex.
For example, a distance runner will feel better consuming the upper end of the recommended range (closer to 65 percent) than a powerlifter would, says Coogan.
“The powerlifter will likely lower their carb intake closer to the 45 percent range in order to bump up their protein needs and intake,” she says.
Certain conditions, such as respiratory or pulmonary disorders and diabetes, are impacted by excess carb intake, she says. However, even those individuals still need to eat some carbs.
Carbs and Weight Management
Low-carb diets are popular for weight management, but they’re not a magic bullet. A 2014 review and analysis published in the journal PLoS One found that low-carb diets had the same effect on weight as other reduced-calorie diets. After two years, there was little to no difference in weight changes.
Carbs face one of three fates after your body digests and absorbs them, Coogan explains.
- Glucose is transported through your bloodstream, for your cells to use as fuel.
- Glucose will be converted into glycogen and stored in your liver and muscle tissue, to be used when glucose levels start to dip or during intense workouts.
- Any excess glucose will be converted to fat and stored in your adipose tissue.
“If you consume a moderate and appropriate amount of carbohydrates (do not eliminate them completely), then you should be able to avoid excess carbs being stored in adipose tissue,” Coogan says.
If you’re considering cutting back on carbs, know that there’s no single definition of a “low-carb” diet. “There’s a lot of gray area,” says Benté. Many “lower-carb” nutrition plans recommend that about 40 percent of calories from carbohydrates, she says, while others following a stricter low-carb diet wouldn’t consider that to be “low-carb.”