Amongst all the nutrition and health news last week was a report that prediabetes increases the risk of cancer by 15 percent. While this isn’t news to me, it did remind me of one of the big circulating nutrition myths: sugar feeds cancer.

While there is an element of truth to this theory, the statement itself has been taken out of context for more than 70 years, falsely leading people to think that if they cut all sugar and refined carbohydrates out of their diet, that they will be able to “starve” their cancer.
It’s true that cancer cells use glucose (sugar) for fuel, but so do all of our other cells. Very active and/or quickly dividing cells (including cancer cells, brain cells, heart cells and the cells that line our intestines) require even more glucose. In short, you can’t starve cancer cells without also starving healthy cells.
Looking at the bigger picture, a diet high in refined sugar and carbohydrates can promote inflammation, suppress immune function and, over time, contribute to insulin resistance—all of which can create conditions in the body that may encourage the initiation and progression of cancer.
The insulin resistance part of that little trifecta is what brings us back around to prediabetes and cancer risk. Your pancreas secretes insulin in response to rising blood sugar levels, as happens after a meal. Insulin molecules latch on to glucose molecules floating around in your blood, then “dock” into insulin receptors on the outside of your cells, prompting the cells to open their doors so the insulin can escort the glucose inside. Each cell then converts the glucose into the fuel it needs to carry out its various functions. This lowers your blood glucose levels to their pre-meal state.
If you are insulin resistant, your pancreas secretes insulin, but it has trouble docking into the insulin receptors, which means that glucose can’t get into the cells, and your blood glucose levels remain high. Your pancreas pumps out more and more insulin in an effort to force those cells to let the glucose in. At first, this may work, but as insulin resistance worsens, even this insulin full-court press may not work anymore. Your pancreas may also wear out and lose ability to produce insulin at all. Insulin resistance is the hallmark of prediabetes and type 2 diabetes.
Now, about those insulin receptors. Cancer cells have insulin receptors, too. They have a LOT of insulin receptors, because they want a lot of glucose. But insulin has other functions, too. One important one is as a growth promoter. Do you really want to encourage cancer cells to grow?
So it’s not the sugar, per se. It’s the insulin. One way to promote healthy blood sugar and insulin levels is to eat a healthy diet that minimizes refined sugar and flour and the heavily processed foods that contain these ingredients, usually along with unhealthy fats and insane amounts of sodium.
Regular exercise is also key for maintaining healthy blood sugar levels, whether you have a problem with high blood sugar or not. Physical activity helps reduce insulin resistance. If you already have prediabetes or full type 2 diabetes, then taking steps to keep it under control will help counteract this estimated 15 percent increased cancer risk.
It’s important to remember that many things affect our cancer risk, for better or for worse. Our genes, what we eat and drink, how much we move our bodies, our levels of stress and quality of sleep, chemicals and toxins we are exposed to in our environments.

There’s no one magic bullet for preventing or fighting cancer, but there are many things you can do to support your body’s natural cancer-fighting mechanisms. Going on a 100 percent sugar-free diet, which can be difficult, all-consuming and socially isolating, does not need to be one of them.

If you are in the Seattle area and are interested in learning more about these topics, and specifically how you can create a cancer-preventive diet, you can book an appointment with me or register for one of my free upcoming classes.