Colloquial conversation around cancer has suggested a clear cause-and-effect between sweets and tumor growth. Here's what's likely behind it.
Does Sugar Feed Cancer? Here’s What a Cleveland Clinic Expert Says
Published on Mar. 29, 2025
More than 2 million Americans were diagnosed with cancer in 2024, according to estimates from the National Cancer Institute. Considering the pervasiveness of the disease, research persists around dietary patterns that affect the likelihood of cancer development. Lately, the notion that you should stop eating sugar because it “feeds” cancer has been a growing message.
What’s behind this idea? It’s probably a little oversimplified, says an oncology registered dietitian at the Cleveland Clinic. “When we eat anything with carbohydrates, whether that’s soda or ice cream or better carbohydrates like fruit and whole grain bread—some of those carbohydrates get broken down into a sugar called glucose, and that’s a good thing,” says Paige Welsh, RD, LD. “Systems like our brain and muscle regeneration actually operate best if they’ve got some of that glucose.”
No research has confirmed that eating sugar is directly linked to impacting cancer cells growth or causing people develop cancer, according to the Cleveland Clinic. So while cancer cells, much like other cells in the body, need sugar to survive, Welsh says it’s not quite a straightforward cause and effect.
Instead, a key diet focus of cancer prevention should be on reducing added sugars, she explains, since those sugars can contribute to health issues often linked to cancer, such as obesity. National data suggests the main culprits of added sugars in American diets are sugar-sweetened drinks (such as soda or other soft drinks), sweets, and desserts. However even yogurts, cereals, and other “healthy” foods contain sugars, which is why we might want to think of these as more of a treat than a health food.
It’s also possible that if you’re filling up on sweets, it’s less likely that you’re getting essential nutrition such as the fiber, vitamins, and antioxidants that help keep diseases like cancer at bay.
So, how much sugar can you actually eat per day? Welsh suggests women have no more than 25 grams of added sugar per day, while men should stick to 36 grams or fewer daily.
“However, less is best, so check those labels and make sure you’re not getting an overabundance,” Welsh said in a video interview from the Cleveland Clinic. She also recommends people “stick to whole foods with naturally occurring sugars,” such as fruit.
If you find yourself regularly craving sugar, it could be a sign that you need more protein. Otherwise, try to remember moderation when it comes to indulging your sweet tooth.
About the expert
|
For daily wellness updates, subscribe to The Healthy by Reader’s Digest newsletter and follow The Healthy on Facebook and Instagram. Keep reading:
