Happy 2026 to all my Cancer Dietitian readers, new and “seasoned”! We’re going to start the New Year off with some myth busting, which I know you all love!
This is one of the most common questions I get. And it’s not just me. It’s oncology dietitians and treatment center employees everywhere!
“Does Sugar Feed Cancer?”
Here’s the bottom line:
While technically there is a little bit of truth to the idea that cancer cells are nourished by glucose. However, the statement that “Sugar Feeds Cancer” is considered a MYTH.
Every cell in the body requires glucose for fuel, including cancer cells, so in that sense, sugar does feed cancer. BUT… sugar also feeds the rest of your body and you cannot pick and choose which cells get what nutrients/fuel.
For those who are going through treatment, remember that your healthy cells need energy especially during this time. Avoiding sugar completely will not help treatment, but it could leave your healthy cells low on energy.
At this point, it has not been shown that eliminating dietary sources of sugar and carbohydrate actually results in slower growth of tumors. It does result in your body having to work extra hard to make the glucose that it needs to function.
THE TRUTH ABOUT SUGAR & CANCER
The fact is that all cells, including cancer cells, need sugar in the form of glucose to generate energy. In addition, No one food or food component (including sugar) can cause cancer.
Currently there is insufficient evidence to show a direct link between sugar intake and cancer growth.
WHY DOES CANCER “GLOW” ON A PET SCAN?
Glucose (aka “sugar”) is utilized by all cells in the human body. However, cancer cells metabolize the glucose at a faster rate. The hyperactivity of the cancer cell is what is detected (“glows”) on a PET scan.
HELPFUL COMPARISON FROM A COLLEAGUE!
Cells use glucose (sugar) the way cars use gas. Normal cells use a reasonable amount of gas, but cancer cells are gas guzzlers!
“During cell division, more glucose is used, much like an accelerating car uses more gas. Normal cells divide at varying rates, some every 3 days and some every 3 months, or more. After cell division, it returns to more of an idling state, using less glucose.
Cancer cells are like cars with the accelerator stuck to the floor, using glucose at high rates because they are dividing at much faster rates than normal cells.”
-Angelea Bruce, RD, CNSC, CSO (Board Certified Specialist in Oncology Nutrition)
ADDED SUGAR vs. NATURAL SUGAR
Carbohydrates and sugars are an important part of a healthy diet.
There are two basic forms of sugar: Added sugar and Naturally occurring sugar.
Added sugars are simple sugars that we add to our foods like table sugar, honey or syrup. Most added sugars are consumed via processed foods and sugar-sweetened beverages.
Naturally occurring sugars are the sugars that are found in whole, unprocessed foods such as fruits, milk, vegetables and grains. These are called complex carbohydrates.
Complex carbohydrates are also broken down into the basic sugars and other nutrients before they are absorbed. The digestive process for complex carbohydrates requires more work than digesting simple sugars, and therefore they take longer to digest.
Complex carbohydrates contain fiber, vitamins, minerals and phytochemicals in addition to natural sugars. All of these nutrients are important to overall energy, health and immunity.
Want to know more about carbs and how they work in the body? Check out my webinar here: Carbs: Yes, No or Maybe?
CANCER PROTECTION
There is strong evidence that a diet filled with mostly plant foods and moderate to minimal amounts of added sugars can lower risk for cancer and increase overall health and immunity.
BOTTOM LINE:
- Glucose (“sugar”) comes from all carbohydrate foods. We can’t control which cells get the glucose.
- If we don’t provide our body with enough glucose through food, our bodies are forced to produce it in order to meet the needs of all cells.
- Making glucose results in muscle loss and a weakened immune system which is the last thing you want during treatment!
- Whenever possible it is best to provide nutritious sources of glucose regularly throughout the day.
Here’s the thing. You might have been told this information from someone who had very good intentions and maybe even was your medical provider, best friend, or someone you thought you could trust. And then here I am telling you the opposite. You should always be able to fact check your sources. So here’s a few other solid resources you can check into on this topic:
- Stanford University Medicine publication – The sugar-cancer connection: Five things you should know
- MD Anderson – Should cancer patients avoid sugar?
- Memorial Sloan Kettering Cancer Center – The Lowdown on Sugar and Cancer
- The American Institute for Cancer Research – The Sugar and Cancer Connection
Are you intrigued by this myth? Check out my webinar on Cancer Nutrition Hot Topics here!
I hope you have a great start to this New Year!
-Julie
