The question does “sugar feed cancer” has sparked widespread concern and countless questions among my patients and cancer patients around the world. It’s a phrase that resonates with fear. Yet, the answer to whether sugar fuels cancer is not as straightforward as it may seem. In this post, we’ll delve into the intricate relationship between sugar, sources of carbohydrates, and cancer growth. We’ll shed the some light on the best approach forward to reducing the risk of cancer and its recurrence.

Does Sugar Feed Cancer Cells?

The notion that sugar fuels cancer is a familiar concern among my patients. For many cancer survivors, the question is whether or not they should part ways with carbohydrates and their beloved treats.

Surprisingly, though, in my previous post titled “5 Cancer-Fighting Foods to Avoid,” you won’t find sugar on the top-five list. So, does sugar genuinely nourish cancer cells?

The answer is yes – sugar does feed cancer, but there’s more to the story. Sugar also serves as the primary energy source for all of our healthy cells. Allow me to explain.

Explaining Sugar & Glucose

Every time we consume carbohydrates, our bodies convert them into sugar, or glucose. While there are various types of sugar (such as maltose and sucrose), let’s simplify things and use “sugar” and “glucose” interchangeably.

Glucose = Sugar (for the simplicity of this blog post explanation)

Glucose is the preferred fuel for EVERY cell in our body. Muscles, the heart, and even the brain favor it. Its significance to our bodily functions is so paramount that our bodies can synthesize glucose from fat and muscle when it’s in short supply. For those intrigued by the science behind it, this process is known as gluconeogenesis.

So, if we were to deprive cancer cells of all sugar (or glucose), would they wither away? Yes. But, what would happen to our healthy cells? They, too, would struggle to survive or fight against cancer effectively.

Here’s Another Perspective:

Would cancer cells die without oxygen? Undoubtedly. Yet, so would we.

The Connection Between Sugar, Insulin, and Cancer

Research demonstrates that it’s the connection between sugar and insulin, or more precisely, insulin resistance, that most significantly influences cancer growth, along with the risk of other chronic diseases. (1)

What causes high levels of insulin and insulin resistance? Surprisingly enough, sugar nor a carbohydrate-rich diet causes insulin resistance. Rather, a diet high in fat and animal products (which are naturally high in or higher in fat) (2).

Simply put, fat and the toxic breakdown of it within our cells causes insulin to not work correctly. When insulin does not work correctly, glucose cannot enter the cell causing it to stay within the bloodstream resulting in high blood sugars. This is insulin resistance.

Take a Moment to Consider:
Many think of donuts as full of carbs and sugar, when in fact, they have more fat than sugar. Sugar isn’t necessarily the primary issue, but rather high amounts of fat (in particular, saturated and trans fat in the case of most donuts).

Rather than fixating on a low-carb, high-fat diet—a popular trend nowadays—compelling evidence suggests that a diet primarily composed of carbohydrate-rich, whole plant foods is crucial for cancer risk.

What is essential is to distinguish between carbohydrates sourced from added sugars or refined sources versus those derived from wholesome grains, fruits, vegetables, and legumes. The latter group is linked to longer life and a reduced risk of cancer and chronic diseases (3), while the former, typical in the standard American diet, lacks essential nutrients and phytochemicals vital for human health.

In Summary

It is not sugar itself (or, glucose) that increases the risk and progression of cancer, but rather its relationship with high insulin levels and insulin resistance — commonly caused by a high fat diet.

Focusing on a nutrition pattern abundant in whole grains, legumes, fruits, and vegetables – which contain ideal sources of carbohydrates – is demonstrated by research to be the best nutrition approach for reducing the risk of cancer and its recurrence. 

References:

1. Arcidacono, B., Iritano, S., Nocera, A., Possidente, K., Nevolo, M., Ventura, V., . . . Brunetti, A. (2012). Insulin Resistance and Cancer Risk: An Overview of the Pathogenetic Mechanisms. Journal of Diabetes Research, 2012. Retrieved January 11, 2019, from https://www.hindawi.com/journals/jdr/2012/789174/.
2. Greger, M., MD, FACLM. (2017, January 6). Retrieved January 08, 2019, from https://nutritionfacts.org/video/what-causes-insulin-resistance/.
3. Sahyoun NR, Jacques PF, Zhang XL, et al. Whole-grain intake is inversely associated with metabolic syndrome and mortality in older adults. Am J Clin Nutr. 2006 Jan; 83(1):124-31.

Blog Updated September 2023