Does sugar feed cancer?
The idea originally came from the discovery that cancer cells use sugar without oxygen (glycolysis) more than regular cells do, called the Warburg effect (1). But it’s not sugar that CAUSES this change. Cells turn cancerous for many reasons, and THEN the Warburg effect takes place.
All body cells in your body need sugar for energy, and there is no evidence that we know of that restricting sugar in patients with cancer helps them recover faster. Rather, many cancers burn a lot of calories, and cancer patients need to be adequately fed to avoid malnutrition (2).
A systematic review of 24 studies looking at sugar and various cancers found that most studies find no link between total sugar intake and cancer. Only 2 of 15 studies on added sugars indicates an increased risk, but looking at sugary DRINKS, the risk was clearly higher. (3)
Why might this be? The difference between sugary drinks and added sugar from food is that sugary drinks are much easier to overconsume when it comes to calories. Too many calories leads to obesity, obesity increases the risk of cancer. (4) Too much fat around your organs is thought to stress your cells increasing risk of developing cancer.
In other words: sugar doesn’t DIRECTLY seem to cause cancer, but it could INDIRECTLY influence cancer risk if consumed in a way which leads to obesity.
1. Vander heiden et al. Understanding the Warburg effect: the metabolic requirements of cell proliferation. Science. 2009;324(5930):1029-33.
2. Calleja fernández et al. Food intake and nutritional status influence outcomes in hospitalized hematology-oncology patients. Nutr Hosp. 2015;31(6):2598-605.
3. Makarem et al. Consumption of Sugars, Sugary Foods, and Sugary Beverages in Relation to Cancer Risk: A Systematic Review of Longitudinal Studies. Annu Rev Nutr. 2018;
4. World Cancer Research Fund/American Institute for Cancer Research. Diet, Nutrition, Physical Activity and Cancer: a Global Perspective. Continuous Update Project Expert Report 2018. Available at dietandcancerreport.org