Sugar and Cancer

By: Sabrina Oliver, RD, CSO, CDN

One commonly asked question asked by oncology patients is “Does Sugar Feed Cancer?” Eating sugar can be a source of fear and anxiety due to misinformation in the media. With holidays coming up, there are lots of delicious sweets around, so now is the perfect time to address this topic.

Currently, there is no evidenced based research to show sugar causes cancer. We know that all cells, including cancer cells need sugar, called glucose, for their primary source of energy. Glucose is found in any food that contains carbohydrates. This includes healthy whole grains, fruits, vegetables, and dairy products in addition to refined carbohydrates such as white bread, pasta, candy, soda, and many desserts. 

The question is if you eliminate sugar from your diet, will the cancer cells starve and stop growing?

The fact is that even without eating sugar or adequate carbohydrates, our bodies will make glucose from other sources, including protein and fat. 

What is important to know is that eating a diet high in simple sugars (white bread, pasta, cake, cookies, and/or sugar sweetened beverages) can lead to overweight and obesity. Research shows that being overweight or obese can increase the risk of several types of cancer including colorectal, ovarian, and pancreatic cancer. 

If you have cancer, it is important to try to eat adequately to prevent unintentional weight loss, breakdown of muscle or malnutrition. Some treatment related side effects can cause poor appetite and gastrointestinal distress. Therefore, always try to eat small, frequent meals of nutrient rich food sources to meet your nutritional needs – and if you have questions you can ask one of our registered dietitians.

If you are worried about risk factors for developing cancer:

  • maintain a healthy weight
  • choose whole grain breads, fresh fruits and vegetables, and legumes with a focus on fiber
  • avoid sugar sweetened beverages and added sugars
  • fill half your plate with fruit and vegetables; the other half should be split between whole grains and lean protein

Here is a recipe for Peanut Butter Cookies. 

*Serves 12-14 cookies. Recipe adapted from Gimme some oven.


  • 2 eggs
  • 1/2 cup brown sugar
  • 1 teaspoon baking soda
  • 1/4 teaspoon salt
  • 1 teaspoon vanilla extract
  • 1 cup peanut butter
  • 1 cup old-fashioned oats
  • 1/2 cup semisweet chocolate chips


Heat the oven to 350°F. Line a cookie sheet with parchment paper. In a large bowl, whisk eggs and brown sugar together until smooth. Sprinkle with baking soda and salt and stir until combined. Add the vanilla and peanut butter, and stir until smooth.  Stir in oats and chocolate chips, until combined. Use a large cookie scoop (about 3 tablespoons) to scoop the dough onto prepared baking sheet. Use a spatula to slightly flatten the tops of the dough balls, and sprinkle with a pinch of salt. Bake for 10 minutes. Remove from oven, cool on the baking sheet. Serve warm and enjoy!