Does Sugar Feed Cancer?

Preventing cancer isn’t as simple as avoiding sugar. Consuming some sugar for energy is necessary for your body. Too much sugar may be linked to obesity, which is directly linked to cancer development.

You have probably heard to avoid sugar because “sugar feeds cancer.” This is partially true, but it can be misleading.

Sugar can seem nearly impossible to avoid, as you find it in traditional desserts, processed foods, and more naturally in the form of fructose and glucose in breads, fruits, and so many things we eat each day. But you can find healthier alternatives when it comes to sugar consumption.

Here’s what you need to know about how your diet may affect your cancer risk or even your cancer treatments.

The American Cancer Society (ACS) explains how obesity is related to developing cancer. The ACS cites sugar-sweetened drinks (like soda) and processed foods high in added sugar and fat.

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There are 13 types of cancer that may be related to obesity. In turn, this means they may be related to high sugar and fat consumption.

• breast cancer
• prostate cancer
• colorectal cancer
• kidney cancer
• liver cancer
• pancreatic cancer
• uterine and ovarian cancers

Obesity is also linked to increased insulin resistance and type 2 diabetes, which is another risk factor for cancer. While sugar has a role, there are many more variables at play, including body fat, comorbid inflammatory conditions, and the influence of hormones called adipokines.

Researchers continue to explore the link between sugar and cancer to discover if there’s a straight line between the two or if obesity is the most direct link. So far, the most compelling evidence surrounds breast cancer.

Yes. All cells — healthy cells and cancer cells — use sugar for energy.

Cancer cells consume 10 to 15 times more glucose than normal cells. That said, sugar alone does not necessarily cause cancer to develop or grow. Instead, it’s just what the cells use for energy.

More research is also ongoing in this area.

Other foods that might feed cancer cells

The National Cancer Institute shares that most studies on humans have not shown a direct link between any food and its ability to cause or prevent cancer.

Foods/ingredients that may increase a person’s risk include:

• excessive alcohol
• acrylamide
• artificial sweeteners
• charred meat

Researchers say that most studies about the direct connection between sugar and cancer have been inconclusive. Instead, the relationship may be more complicated and depend on the person, their specific cancer, and other individual factors.

Eating sugar will not make cancer grow. Likewise, avoiding sugar entirely will not starve cancer and make it go away. Instead, a diet high in sugar and fats may lead to obesity, inflammation, and insulin resistance.

Researchers say it’s this broader connection that may promote tumor growth.

Again, excess sugar consumption is associated with obesity, inflammation, and insulin resistance. The connection between all these moving parts is what may increase a person’s risk for cancer.

Of all cancers, researchers say the types that respond most to sugar are breast cancer , endometrial cancer, and colorectal cancer. Other research potentially links esophageal adenocarcinoma with excessive sugar consumption.

It’s important to note that the ACS’s guidelines for cancer prevention do say to limit sugar consumption, though not by how much. More specifically, they say to not drink sugar-sweetened beverages.

Chemotherapy is a cancer treatment that kills off both cancer cells and normal cells in the body. One side effect of chemotherapy is low blood sugar (hypoglycemia) due to things like nausea, vomiting, ad decreasing appetite.

As far as consuming sugar while actively in chemotherapy, there isn’t enough research to show it has an impact one way or another. Experts do share that drinking beverages high in sugar may make the side effects of chemotherapy, like diarrhea, worse.

In addition, foods that are high in sugar, like packaged desserts, provide mostly empty calories and may not support your body as well as whole foods during chemotherapy.

The ACS recommends avoiding or limiting the following foods:

• meats that are red or processed
• beverages that are sweetened with sugar
• other foods/grains that are highly processed

While this list does not say to avoid specific sugary foods, many highly processed foods contain particularly high amounts of sugar. The American Heart Association recommends consuming no more than 6 teaspoons of sugar a day for women and 9 teaspoons a day for men.

The ACS recommends eating a varied diet with a focus on whole fruits, vegetables, beans and legumes, and whole grains.

Preventing cancer isn’t as simple as avoiding sugar. You need to consume some sugar for energy and to fuel all the cells in your body. Excess or added sugar in packaged foods or beverages may be linked to obesity, which is directly linked to cancer development.

Before you restrict your daily intake, speak with your doctor if you have concerns. Your doctor may refer you to an oncology dietitian who can help you come up with an eating plan that works best for you.

Last medically reviewed on March 9, 2023