Is There a Link Between Sugar and Cancer? What Research Shows

The link between sugar and cancer is often misunderstood. Explore what current evidence says about glucose, added sugar, cancer risk, and the claim that cutting out sugar can starve cancer cells.

Key Takeaways

Current evidence does not show that eating sugar directly causes cancer or makes an existing cancer grow. Also, there is no evidence that not eating sugar at all will shrink the cancer tumour or make it disappear altogether.¹

It is human to be overcautious, especially when you or your loved ones are dealing with cancer. However, during such times of anxiety, we tend to set evidence aside and trust health information that promises a quick fix or a miracle cure. This information can influence your diet and lifestyle choices in ways that may prove unhealthy over time.

Why Does the Sugar and Cancer Myth Persist?

Sugar Biology – Taken Too Far: The most probable reason this misconception persists is that cancer cells do use glucose for energy and often show altered glucose metabolism.²

Glucose is a simple sugar that your body utilises for energy. Blood glucose comes from dietary carbohydrates as well as from the body’s own glucose-producing pathways.

Both healthy and cancer cells use glucose as their main energy source.

Cancer cells can use glucose differently from healthy cells, and many cancer cells show increased glucose uptake to support their metabolic needs and growth.²

What Evidence Says

A 2023 systematic review and dose-response meta-analysis brought together 37 prospective cohorts (about 4.5 million people).  The review found consumption of each additional 250 mL (about one glass) of sugar-sweetened beverages (SSBs) per day was associated with a higher risk of breast, colorectal, biliary tract cancer, and prostate cancer.

However, the evidence supporting these associations was limited, and the absolute increases in cancer risk were small. The authors suggested that excess body weight may partly explain these associations.³

Reasons to Interpret this Evidence Cautiously

• All the studies reviewed were observational. Observational studies often fail to account for hidden factors that might affect the conclusion (such as diet, exercise, alcohol, smoking, and access to healthcare).
• The researchers collected diet information from participants through a questionnaire. Such a method is prone to people forgetting smaller details about their diet.
• When people say “sugar”, they may be talking about several different things. The scientists studied the effect of SSBs. The term “sugar-sweetened beverages” also needs careful interpretation.
• Studies may define beverages differently, and SSBs should not be treated as interchangeable with foods containing added sugar or with 100% fruit juice. Each can contain other ingredients that may affect the study results.
• Much of the available human evidence highlights the need for more rigorous research to better understand the relationship between sugar-sweetened beverages and cancer risk.

Why Cutting Out All Carbohydrates is Not a Cancer Treatment

The belief that eliminating sugar from your diet will starve cancer cells is unfounded. The body doesn’t have a separate glucose supply reserved for cancer cells. Therefore, eliminating dietary sugar cannot selectively deprive cancer cells of glucose.

According to the Dietary Guidelines for Indians, a balanced diet provides around 50-55% of total calories from carbohydrates. Nevertheless, calorie needs vary depending on age, sex, physiological status, and physical activity level.⁴

Furthermore, if you are undergoing cancer treatment, a restrictive diet deserves particular caution. Cancer treatment can cause side effects such as low appetite and digestive issues. A carbohydrate-deficient diet may make it harder to meet your daily calorie and nutrient needs.

A very high-sugar diet needs attention. Such a diet may contribute to excess weight gain and obesity, with an associated increased risk of developing several types of cancers.¹

Healthy Strategies to Limit Added Sugar

To limit added sugar:

• Read labels for information about added sugar and total calories
• Consider avoiding drinks/beverages sweetened with added sugar
• Choose whole fruit over juices
• Choose whole grains more often than refined grain products
• Limit mithai, cake, chocolates, and ice cream to an occasional indulgence.

Remember, occasional indulgence does not undo a healthy lifestyle.

Fact-Checking Health Information

Be curious when a claim promises a miracle cure. When you encounter health information that asks you to make drastic changes to either your diet or lifestyle:

• Look for the original source of the claim, not a news article or a blog.
• Ask: Is the claim based on scientific evidence or a one-off personal experience?
• Was the evidence from humans, animals, or laboratory models?
• Findings from animal studies do not indicate the same results apply to humans.
• Be cautious of trusting health claims on social media or messaging platforms.

Conclusion

While some observational studies have reported associations between high intake of sugar-sweetened beverages and certain cancers, these findings do not establish that sugar itself causes cancer.

Cancer prevention guidelines from organisations such as the American Cancer Society recommend limiting added sugars. This can help prevent excess weight gain and obesity – both associated with risk of several types of cancer.

If you are a cancer survivor or are currently undergoing cancer treatment, discuss any questions about dietary changes with your oncologist or nutritionist.

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References

1. Common Cancer Myths and Misconceptions – NCI [Internet]. 2023 [cited 2026 Oct 10]. Available from: https://www.cancer.gov/about-cancer/causes-prevention/risk/myths
2. Hasan N, Yazdanpanah O, Khaleghi B, Benjamin DJ, Kalebasty AR. The role of dietary sugars in cancer risk: A comprehensive review of current evidence. Cancer Treatment and Research Communications. 2025 Jan 1;43:100876. doi:10.1016/j.ctarc.2025.100876. Available from: https://www.sciencedirect.com/science/article/pii/S2468294225000140
3. Pan B, Lai H, Ma N, Li D, Deng X, Wang X, et al. Association of soft drinks and 100% fruit juice consumption with risk of cancer: a systematic review and dose–response meta-analysis of prospective cohort studies. Int J Behav Nutr Phys Act. 2023 May 15;20(1):58. doi:10.1186/s12966-023-01459-5. Available from: https://link.springer.com/article/10.1186/s12966-023-01459-5
4. ICMR-NIN Expert Committee. Dietary guidelines for Indians-2024. [Internet]. Hyderabad: Indian Council of Medical Research–National Institute of Nutrition; 2024 [cited 2026 Oct 10]. Available from: https://nin.res.in/dietaryguidelines/pdfjs/locale/DGI_2024.pdf

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