Does Sugar Really Cause Cancer? We Explain

Sugar, specifically refined processed sugar, has always been something you should enjoy sparingly. But, increasingly, there’s a campaign against sugar as a public health menace. And now there are claims that it may be linked to cancer. So what’s the science? And what’s the healthy thing to do?

  • “Sugar” means “processed, refined sugar.” A sugar, in the scientific sense, is just a sweet tasting soluble carbohydrate. And anything with a taste you’d classify as “sweet,” from carrots to carrot cake, probably has some form of sugar in it. In fact, our body turns most carbohydrates it consumes into simple sugars. The difference is that a piece of fruit, or a slice of whole grain bread, has other nutrients, including fiber, which modulates your blood sugar. There’s no fiber in that froofy drink or that candy bar.
  • That said, refined sugar in small doses is extremely unlikely to kill you. With any health concern, remember the toxicologist’s mantra: It’s not the substance, it’s the dosage. The occasional silly coffee drink, cookie, or slice of cake shouldn’t be a source of concern, although brace yourself for the sugar crash. But a diet heavy in refined sugars, be they table sugar, high fructose corn syrups, or other refined sugars? That’s a problem, and it’s looking like a bigger and bigger one all the time.
  • Is there a hard link between a sugar-heavy diet and cancer? Not yet, but a recent study does raise some fairly serious concerns. Researchers studying yeast recently found that fermentation of sugar triggered cell proliferation. That is, you give the yeast some sugar, and as they turn it into alcohol, the yeast grows like it’s on steroids. Why is that important? Because cancer cells tend to act the same way, even when they can use oxygen for fuel, which is called the Warburg effect. And there are strong indicators that what happens to yeast cells happens in mammalian cells as well. Put simply, cancer cells might use excess sugar in the body as a form of fuel.
  • However, diet is only one factor in cancer. Keep in mind that cancer isn’t one disease, but a family of diseases, with a variety of different contributing factors from exposure to the sun to genetics to exercise. There’s no one tipping point of behavior, no one thing you need to change to avoid cancer. Will eating less sugar help? Most likely, even if only indirectly by helping you avoid diabetes and other health complications. But it won’t be a cure, either.

In the end, it’s a question of lifestyle and quality of life over time. Eating better and exercising are best seen as ways to improve your quality of life and your overall health. Taking half an hour to go for a walk and eating more vegetables will just generally help you feel better, but everybody’s going to be different when it comes to the specifics. Conversely, grabbing a cupcake once a week and having the occasional afternoon on the couch binge-watching Netflix won’t herald the arrival of the Grim Reaper. It might even be good for your mental health to unplug for a little while, which can help your physical health. So, don’t focus on demonizing foods or feeling guilty about what you eat. Instead, learn as much as you can about what you eat, and what you do, so you can make informed choices.