What Makes Refined Carbohydrates So Unhealthy? RDs Explain Why They're Not the Most Nutritious Option

Certain types of carbs don't serve you like others do—here's how to strike the right balance.

Carbohydrates have received a bad rap over the years, but not all carbohydrates are bad for you. In fact, carbs are one of the key macronutrients your body needs everyday to function properly—you just need to know what kind of carbs to reach for. There are whole, unrefined carbohydrates that come from nutritious foods—whole grains, beans, fruits, and vegetables. And then there are refined carbohydrates, often called processed carbohydrates. Refined carbs are the ones to watch out for and eat in limited quantities. Why? Because they contain very few nutrients your body can actually use.

What exactly are refined carbs?

"Refined carbs are carbohydrate foods that have been processed to remove natural fibers, bran, germ, and the nutrients in these parts from the grain," says Lauren Minchen, MPH, RDN, CDN, nutrition consultant for Aspire, an AI-driven visual diet diary app. "What's left is the starch and caloric portion of the grain, with a minimal amount of protein."

Refined carbohydrates generally fall into two categories: refined grains and added sugars.

Refined Grains

White flour is probably the most recognized refined grain, showing up in everything from bread and pasta to pretzels, doughnuts, snack bars, and cookies. "Whole grains have three parts: bran, germ, and endosperm," explains DJ Blatner, RD, author of The Superfood Swap. "Refined grains are processed to remove the bran and germs, which removes many nutrients like iron, B vitamins, and fiber."

Added Sugar

This is the other main category of refined carbohydrates, encompassing all of the sugars that don't occur naturally in a whole food, like fruit. "Added sugar is definitely everywhere, and there are many synonyms for sugar such as cane juice, high fructose corn syrup, glucose, dextrose," says Blatner. "Even brown rice syrup, honey, and maple syrup are considered added sugar." Added sugar can be sneaky and appear in salad dressings, sauces, yogurts, and cereals, making it hard to avoid if you're not careful about reading the ingredient labels of packaged foods.

Are refined carbohydrates truly bad for you?

While undeniably delicious, this kind of carbohydrate sadly isn't the best option for you. "Refined carbs are void of essential nutrients, like B vitamins, magnesium, iron, phosphorus, manganese, and selenium—all of which are in the bran and germ [that get removed when processed]," Minchen says.

"In addition, [the lack of] fiber in refined carbs equates to a greater blood sugar spike and risk of poor blood sugar management," she adds. This poor sugar management can often lead to more serious issues like Type 2 diabetes, obesity, chronic inflammation, and heart disease.

Because refined carbohydrates lack any real nutrition, they aren't very filling or satisfying, and the body digests them rapidly. This can often lead to the need to eat more and difficulty managing diet choices, cravings, and healthy weight.

How much is OK to consume?

Don't panic: You don't need to cut the yummiest foods out of your life completely—but as with all things, moderation is your smartest move when it comes to things like white bread products, white rice, pastas, soda/juices, packaged snacks, and other refined carbs.

"Ideally, refined carbs should be consumed sparingly: up to two to three servings per week for the average person is OK," Minchen says. "For someone with poor blood sugar regulation or diabetes, consuming refined carbs even less often may be recommended."

One healthy way not to feel like you're missing out on the goodness of carbs is to make sure you're prioritizing whole grains over refined grains. The USDA Dietary Guidelines for Americans suggests we make "half our grains whole," says Blatner. "That means, for women (30 to 60 years old) the total daily grain target is 5 to 7 ounces per day, and for men, 7 to 10 ounces equivalents per day—with only half of those being refined carbohydrates."

To put that in perspective, 1 ounce is equivalent to one slice of bread, one cup of cereal, or a half cup of cooked rice or pasta.

Be careful with the added sugars. The American Heart Association recommends limiting daily added sugar to 6 teaspoons (25 grams or 100 calories) for women and 9 teaspoons (36 grams or 150 calories) for men.

Refined carbs have their occasional perks.

Although the bad ultimately outweighs the good, refined carbohydrates do provide quick energy in a pinch."Quickly digested energy before a workout is important in order to prevent cramping that can come from eating fiber right before a workout," says Minchen, who recommends something like fresh fruit juice or white bread for these circumstances. "Additionally, eating something quickly digested right after a workout can boost muscle recovery and buffer the protein you consume to help maximize its muscle-building effect."

Just make sure you avoid any added sugars wherever possible. If you are going to have refined carbohydrates, it's best to find the ones enriched with added vitamins and minerals, advises Blatner. "But it's always best to choose whole grains," she says.

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