Carbs get a bad rap. We’re taught that carb-heavy foods should be avoided, but the reality is that carbohydrates are essential to a balanced diet. About 45% to 65% of our daily calories should come from carbohydrates. Some are usually called “good” and others “bad,” because not all carbs are created equally when it comes to your nutrition. It helps to understand why some carbs are less healthy than others, because you shouldn’t swear off the category entirely.
Part of the reason there’s a rising obesity epidemic in the United States is that the typical American diet is high in refined carbs, such as those found in fast food and white bread. “When we look at the standard American diet, we are eating a very high amount of refined carbs and very little in the way of complex carbs, fresh fruits, and vegetables,” explains Julie Smith, RD., a registered dietitian at The University of Toledo Medical Center. “We should fill half of our plate with fruits and vegetables, then a fourth on some kind of lean protein, and then limit those carbohydrate choices to the other fourth of our plate.”
What are refined carbs?
Refined carbohydrates are sugars and starches that have been altered in the process of turning them into packaged foods. They originally come from natural whole grains but are heavily processed to remove the outer shell and seed portion of the grain. After milling the grain, you’re left with better flavored carbohydrates—and food with a longer shelf life.
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Stripping parts of the grain also removes almost all essential vitamins, nutrients, and dietary fiber. “The outer portion is actually what gives our body all the nutrition that grains give us and all the fiber, so they processed it to take that away,” says Smith.
You can find refined carbohydrates in white bread, pizza dough, cornflakes, and rice.
What’s the difference between complex carbs and refined carbs?
If refined carbohydrates are the “bad” carbs, complex carbohydrates are the “good carbs.” Complex carbohydrates provide nutrients and fiber that the body needs to sustain itself.
“We should make sure that at least half of our carbohydrates are complex carbs, such as whole grain and sweet potato, and really try to limit those refined carbs to 50% of our total carbohydrates for the day,” says Smith. You can find complex carbohydrates in oatmeal, whole grain bread, sweet potatoes, and brown rice.
Why should refined carbs be limited?
Refined carbs do little to keep your body running smoothly.
You’ll miss out on essential nutrients
Whole grains and other complex carbs are a rich source of vitamins and minerals. These may include:
- B vitamins: Maintain healthy brain activity and cell function
- Iron: Helps red blood cells carry oxygen from the lungs to the rest of the body
- Fiber: Helps with digestion and keeps you satiated
- Potassium: Regulates blood pressure, and supports muscle and nerve activity
- Magnesium: Helps support muscle and nerve activity as well and helps convert nutrients from food into energy
- Folate: Also known as vitamin B9, eliminates an amino acid called homocysteine that at high levels can harm the body
- Selenium: A mineral that protects against cell damage
You’re more likely to have digestive problems
Your gut bacteria depends on fiber for fuel. Without fiber to feed on, your gut microbiome loses its diversity as all sorts of bacteria, including those that promote good health in your body, die off.
Fiber in whole-grain cereals or pasta can also promote healthy bowel movements and relieve your constipation.
Avoiding refined carbs can help keep chronic diseases at bay
A diet high in refined carbs is associated with:
- Type 2 diabetes
- Heart disease
- Early death
- Poor metabolic health
- Increased cholesterol
Benefits of healthy (complex) carbs
You’ll feel full without overeating
Since refined carbohydrates remove fiber, they do not make you as full as whole grain foods—eating lots of refined carbs can lead to overeating. “Oatmeal or a slice of whole grain bread has complex carbohydrates that take longer for the body to digest and will keep you full until your next meal,” says Smalling. Fiber also releases a chemical called acetate that sends a message to your brain of your satiety.
If you’re looking for a snack between meals, Smalling recommends fruit or veggie slices. They both have complex carbohydrates and are rich in fiber.
Maintains consistent blood sugar levels
All carbohydrates are made up of sugar, but it’s the chemical structure between refined and complex that makes the difference. Refined carbohydrates have only one sugar molecule, while complex carbs have long chains of sugar molecules. The body breaks down both types of carbohydrates and converts them into glucose for energy. However, Smalling says breaking a long chain of sugar takes time, raising blood sugar but at a slow and steady pace.
Keeps your brain running
Your brain runs on carbs—more specifically, the nutrients in the carbohydrates. Magnesium and potassium help neurons send messages to brain cells via electrical activity. Magnesium also helps overexcited neurons frequently firing signals to calm down, bringing it back to a resting state. “Your nerve cells’ first choice for energy is carbohydrates. Why would you want to deprive your brain and nerves of the energy they need?” explains Smalling.
How to choose complex carbs
Both experts agree that reading food labels is the best way to choose foods high in complex carbohydrates. You’ll want to pay special attention to fiber content. “In the United States, people are required to replace the nutrients lost in refined carbs. So you’ll often see on a label that a product is fortified with niacin, riboflavin, and iron, but food brands don’t usually add any fiber back in, and that’s one of the main nutrients you end up still losing,” he explains Smalling. Even if a whole-grain product like brown rice only has a few grams of fiber, it is still better than white rice, which has even less.
The bottom line: Carbs are an important part of any healthy diet, and dietitians agree that complex carbs are better for you than refined carbs. If you feel you may need to adjust your diet for more energy or better overall health, consider consulting a nutritionist. They can help set up a nutrition plan that works best for you.