Myth: People who have cancer shouldn't eat sugar, since it can cause cancer to grow faster

Fact: More research is needed to understand the relationship between sugar in the diet and cancer. All kinds of cells, including cancer cells, depend on blood sugar, also called glucose, for energy. But giving more sugar to cancer cells doesn't make them grow faster. And keeping sugar from cancer cells doesn't make them grow more slowly.

This misconception may be based in part on a misunderstanding of positron emission tomography (PET) scans. These scans use a small amount of radioactive tracer that's usually a form of glucose. All tissues in your body absorb some of this tracer. But tissues that are using more energy, such as cancer cells, absorb greater amounts. For this reason, some people mistakenly believe that cancer cells grow faster on sugar. But this isn't true.

There is some evidence that eating large amounts of sugar may raise the risk of certain cancers, including esophageal cancer. Eating too much sugar also can lead to weight gain and increase the risk of obesity and diabetes, which may raise the risk of cancer.