Websites promoting the idea that sugar “feeds” cancer suggest that eating foods with sugar makes cancer grow faster. As a result, some cancer patients forego eating any sugar, eliminating beneficial foods, such as fruits, that contain essential nutrients.
There is no conclusive research on human subjects to prove that sugar makes cancerous cells grow and metastasize. Avoiding foods with processed sugar is a good idea in general, but eliminating foods with natural sugar won’t stop cancer cells from dividing.
In fact, every cell in the human body, including cancer cells, need blood sugar in the form of glucose for energy. Most people associate the term “sugar” with the white sugar we put in coffee. When talking about biological processes, sugar is a general term for dozens of vital chemical structures in our bodies.
As Julie Baker, Clinical Oncology Dietitian at our hospital outside Atlanta, explains it: “Our bodies use glucose, the simplest unit of carbohydrate, as their primary fuel. Without adequate carbohydrate intake, our bodies will obtain glucose, or fuel, from another source. Possibilities include the breakdown of proteins we eat or proteins stored in our body, which may ultimately lead to muscle loss and malnutrition.”
Eliminating all sugar from a cancer patient’s diet would harm healthy cells that need energy to function.
When Baker meets patients for the first time, some say they’ve eliminated fruit, bread, whole grains, beans, starchy vegetables or dairy out of the fear that “sugar feeds cancer.” Such diets are very restrictive, Baker says, and lacks important antioxidants, phytochemicals, fiber, vitamins and minerals.
“Many types of cancers and treatments make consuming adequate nutrition very difficult. Restricting multiple food groups only makes that job harder,” says Baker, who recommends eating a balanced, plant-based diet.
Similarly, limiting the amount of sugar in your diet is important. Diets high in sugar and refined carbohydrates can lead to overweight and obesity, which indirectly increases cancer risk over time. Certain cancers—including breast, prostate, colorectal and pancreatic—are associated with obesity.
Dietitians advise limiting foods with high amounts of sugar, such as sugar-sweetened beverages. According to the American Heart Association (AHA), a 12-ounce can of regular soda has 8 teaspoons of sugar equaling 130 calories and nutritional value. The AHA recommends:
- 6 teaspoons of sugar (100 calories) per day for women
- 9 teaspoons of sugar (150 calories) per day for men
Most Americans consume twice the recommended amounts. In addition to cookies, cakes and other sweets, sugar is found in pasta sauce, salad dressing and canned vegetables. When reading food labels, look for sugar listed as the first ingredient and be aware of hidden sugar names: fructose, lactose, sucrose, maltose, glucose, dextrose.
Natural sugars—molasses, agave nectar, honey and maple syrup—contain beneficial antioxidants but those, too, should be consumed in moderation.
Learn about the benefits of good nutrition during cancer care.