Good Carb, Bad Carb: 4 Myths Debunked
When you’re focused on losing or maintaining weight, you get plenty of advice about carbs. What’s the truth — should you avoid carbs at all costs, or just certain ones?
Our dietitians reveal the facts behind common carbohydrate myths:
Myth 1: Carbs make you gain weight
“People often say that carbs are fattening. But complex carbohydrates, like whole grains, are not ‘fattening’ foods,” says Kristin Kirkpatrick, MS, RD, LD.
This myth, she believes, may spring from carbs’ effect on insulin. Eating carbohydrates raises your blood glucose and prompts your body to release insulin. This redirects your glucose to cells.
“But it’s the type and quantity of the carbs you eat — not carbohydrates themselves — that cause weight gain,” notes Julia Zumpano, RD, LD. “Many carbs contain excess calories and sugar.”
Examples include desserts; white bread, rice and pasta; and snack foods like chips, crackers and pretzels. These refined carbs are stripped of the outside grain, which contains the fiber and some protein, she says, making glucose levels spike quickly.
Carbs that contain fiber (like brown rice) or protein (like legumes) raise blood glucose more slowly, require less insulin, and keep you full longer. But even complex carbs like whole grains, beans and fresh fruit should be eaten in moderation.
“For weight loss, a basic rule of thumb is to limit your carb intake to about 1 cup per meal (about the size of a coffee mug or woman’s fist),” says Ms. Zumpano.
Keep your carbohydrate intake to around 40 to 45 percent of your total calories, she says. Healthy fats should make up 30 to 35 percent of your total calories, and lean proteins should make up the other 30 percent.
Myth 2: Only white foods contain carbs
“There seems to be lots of confusion about which foods even contain carbohydrates,” says Anna Taylor, MS, RD, LD, CDE. “People often think only rice, bread, pasta, potatoes, sweets and sugary drinks are carbohydrates.”
Think beyond “white foods” to get a more complete list of high-carb foods, she says, which also includes:
- Sweet potatoes
- Winter squash
- All grains, including oats, quinoa and whole wheat
- Yogurt and milk
“High-fiber carbs (like legumes, whole grains, starchy veggies and fruits) and high-protein carbs (like legumes, yogurt and milk) are generally more nutritious than low-fiber carbs (like refined grains, sweets and sugary drinks),” she says.
Myth 3: All white foods should be avoided
“It’s true that white foods like processed grains and sweets are higher on the glycemic index, quickly raise blood sugar and cause inflammation,” notes Rachel Stockle, RD, LD.
But other carb-rich foods — considered “white” due to the color of their inside layer — can be essential to good health. “They contain plenty of phytonutrients, have antioxidant activity and support immunity,” she says.
“For example, potatoes have a particularly bad reputation, but are great sources of potassium, fiber and vitamin C.” Stick to the proper portion size, however, she notes: half of a medium potato. (Medium potatoes weigh about ¼ pound on the produce scale at your grocery store.)
Meanwhile, enjoy these other nutrient-rich white foods:
- Nuts and seeds
- Onions and garlic
Myth 4: Fruit is bad because it’s high in carbs
“People often say that fruit has too much sugar in it,” says Kate Patton, MEd, RD, CSSD, LD. “The truth is that fruit is dense in nutrients. Along with a natural form of sugar called fructose, fruit provides fiber, vitamins, minerals and phytonutrients.”
But many fruits today are far larger than the recommended portions, she cautions. That can make your daily calories and total carbs add up fast.
“One serving of hand fruit (apple, orange, peach, pear or plum) is the size of a tennis ball,” she says. “A 4-inch banana is one serving; so is 17 small grapes.”
She recommends fresh or frozen fruit — without added sugar — over fruit juice. “Fruit juice is more concentrated in fructose but lacks fiber,” she says. (Love fruit juice? Limit your portion to 4 ounces.)
Don’t write off carbs — they play an important role in a healthy, balanced diet.
“Pick carbs that are bursting with fiber and/or protein, vitamins and minerals, and neglect those devoid of nutrients,” advises Ms. Taylor.