A Dietitian’s Strange Affair with Sugar


Karen Wagner, MS, RD
Karen Wagner, MS, RD

At least once a week, if not more, I find myself in the strange position of trying to convince someone to eat more sugar. It is not that I think that everyone should eat more sugar, it’s not that I think sugar is healthy, but the information regarding sugar and cancer gets so distorted by fear and misunderstanding that sometimes, me, a dietitian, gets put in the counter-intuitive position of encouraging someone to eat more sugar.

By the time someone has come into see a doctor in the cancer center, he or she has already received a lot of information from a lot of people. One of the things that people sometimes hear is that sugar feeds cancer.

It should be stated, first of all, that every cell in our body uses sugar for fuel, our brain cells, our immune cells, our blood cells and our muscles. Sugar breaks down easily and provides a lot of energy quickly. Almost all of the cells in our body will use sugar, specifically glucose, even if there are other energy sources in the blood stream, such as fat. Furthermore, our cells can not tell if the glucose that is in the blood stream is from a jelly bean, or from brown rice, each sugar molecule looks the same to our cells.

Cancer cells are our own cells that have mutated and they do use the same fuel source that our healthy cells use. Cancer cells do typically use up more fuel than regular cells, but they too, can not distinguish the source of sugar molecules in the blood stream. This may sound scary, but a number of recent reviews have come out in the past couple of years that do NOT show any relationship between a person’s cancer risk and a person’s sugar consumption. Of the studies that have shown any indication that sugar consumption and carbohydrate intake may influence cancer risk, the increased risk was small. These studies often look at whole diets and often follow people for a long time and I think should provide some comfort for all of us. They indicate that sugar consumption, by it itself, does not seem to effect a person’s risk for getting cancer.

These studies are about people before they get cancer, what about people going through treatment? The main thing we know about nutrition and people going through their cancer treatments is that people who can maintain their weight within about 10 % of their pre-diagnosis weight seem to do better overall. They feel better, they are able to get the full course of treatment planned by the doctor, they have fewer side effects and they have a better long term survival rate. Again, it does not seem to matter what kind of foods people ate, as long as they maintain their weight.

Of course, I am a dietitian. I personally would love it if everyone who goes through cancer treatment could also eat a low sugar, low fat, high fiber, high fruit and vegetable diet. I have absolutely no data to prove that this would be helpful or beneficial, but I just like for people to eat their fruits and veggies. However, what I really want is for the people I work with to get the most from their cancer treatments and to feel as well as they can throughout the process. Because of this, I often encourage people to eat more sugar, or at least, nourishing foods that also contain sugar, especially when someone is limited in what he or she can tolerate. Puddings, cheesecakes, pumpkin pie, smoothies or milkshakes, cookies and milk are often easy for people to eat during treatment, can help people maintain their weight and do provide needed protein and calories.

Sometimes it’s a tough job convincing someone to eat ice cream.