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Women's Health

Does Sugar Feed Cancer?

by Tuesday Hoelscher, RD
sugar cubes

The Truth:

Eliminating sugar during or after cancer treatment will not shrink tumours or reduce recurrence risk. This is one of the most common myths I hear, and it makes sense why people believe it.

Yes, cancer cells use glucose (sugar) for energy. But so does every cell in your body. Organizations like the American Cancer Society specifically address this: sugar does not selectively feed cancer cells. Even if you cut out all carbohydrates, your body isn’t just going to “run out” of sugar. It will make its own using protein and fat. So in reality, you cannot starve cancer cells without also depriving your healthy cells.

Eliminating carbohydrates altogether often creates more problems than it solves

It becomes much harder to meet nutrition needs. It can lead to unintentional weight loss, which is linked to poorer outcomes during treatment. It adds stress, which can actually increase blood sugar levels through stress hormones.

So while it may feel like you’re “doing something,” it’s often not helping in the way you think.

So where did this idea come from?

There is some truth behind the concern, but it’s been oversimplified. Research suggests that high intakes of added sugars, especially from sugary drinks, may be associated  with increased risk of certain cancers over time (like breast, colorectal, and pancreatic).

But this is about long-term patterns, not a single food or ingredient. The concern isn’t that sugar directly “feeds” cancer. It’s that excess sugar can contribute to things like:

  • Blood sugar and insulin spikes
  • Chronic inflammation
  • Changes in gut health
  • Weight gain over time

All of these can influence overall cancer risk.

What to do instead:

Instead of trying to eliminate sugar completely, focus on what actually supports your body:

  1. Pair carbohydrates with protein: this helps keep blood sugar levels more stable and
    keeps you full longer.
  2. Choose more nutrient-dense carbs. Think: Fruit, Whole grains (like popcorn, oats, brown rice), Beans and legumes
  3. Be mindful, not restrictive, with added sugar. It’s okay to limit things like: Soda, Candy, Cakes and desserts

But you don’t need to fear them. Having these in moderate amounts will not harm you.

In conclusion, sugar is not something you need to eliminate to fight cancer, but consistently high intake, especially from processed foods and drinks is worth paying attention to.  The goal is balance, not restriction.

References:

  • American Cancer Society Guideline for Diet and Physical Activity for Cancer Prevention. CA: A Cancer Journal for Clinicians. 2020. Rock CL, Thomson C, Gansler T, et al.
  • Total and Added Sugar Intakes, Sugar Types, and Cancer Risk: Results From the Prospective NutriNet-Santé Cohort. The American Journal of Clinical Nutrition. 2020. Debras C, Chazelas E, Srour B, et al.
  • Dietary Sugar Consumption and Health: Umbrella Review. BMJ. 2023. Huang Y, Chen Z, Chen B, et al.
  • Early-Onset Gastrointestinal Cancers. The Journal of the American Medical Association.2025. Jayakrishnan T, Ng K. Survivorship. National Comprehensive Cancer Network. Updated 2026-04-08.