Ketogenic Cancer Diet

Ketogenic Cancer Diet


What is a Ketogenic Diet?

A ketogenic diet, otherwise known as a keto diet, is a very high fat, moderate protein and low carbohydrate diet designed get your body burning fat as the main fuel. When the body burns fat, it produces ketones. When you have made the switch from glucose during to fast burning, you are said to be  in ketosis.

What is the Connection Between Keto Diet and Cancer?

A German physiologist and medical doctor named Otto Warburg was the recipient of the Nobel Prize in Physiology in 1931 for his discovery of the unique way cancer cells use fuel and generate energy.

In his research, he documented the two common ways a cell can create energy for its needs. One, which takes place in the presence of oxygen, is called Oxidative Phosphorylation. A second, which produces much less ATP (energy) and is predominate when oxygen is limited, is called Anaerobic Glycolysis.

Cancer cells are different though in that they have their own unique energy pathway, which is a hybrid of these two common ways. It is called Aerobic Glycolysis. In other words, despite oxygen being available and the cancer cell having functioning mitochondria, which could use the more efficient system of phosphorylation, the cancer cell prefers to use glycolysis. In microorganisms, this energy pathway is called glucose fermentation.

Since cancer cells prefer to use glucose (sugar) as its energy source, could this mean that by removing sugar from your diet you could starve a cancer cell? This suggestion is certainly being touted on the Internet and is recommended by many alternative cancer practitioners. However, it is also beginning to be tested through clinical trials in conventional cancer treatment settings as well.

Should I Eliminate Sugar from My Diet?

Like most nutrition questions I answer, I like to look at this situation like a cost-benefit question. Let’s examine the costs and benefits of cutting out sugar from your diet.

does sugar feed cancer

What are the Costs to Cutting Sugar Out of My Diet?

If you think of sugar as “added sugar” like cane sugar, beet sugar, honey, molasses, syrup, sweets and candy, then there isn’t really any downside to cutting sugar out of your diet. You will likely lose some body fat, reduce your triglycerides and your dentist will be happy too. But, if you know anything about nutrition, you know that even healthy whole grains, fruits, certain vegetables and legumes are also eventually converted to sugar by digestion. Avoiding these healthy foods could certainly come at a cost.

Healthy carbohydrate foods, although they are eventually converted to sugar, ALSO contain fibre including prebiotics, beneficial phytonutrients, and important vitamins and minerals. These foods have been shown to help support the immune system, reduce chronic inflammation and act on cancer cells directly. Eliminating these healthy foods could certainly be detrimental to a cancer thrivers risk reduction strategy.

What are the Benefits to Cutting Sugar Out of My Diet?

There is preliminary evidence that some cancers (particularly brain cancers) benefit from a very strict reduction of all sugars from the diet (from healthy and unhealthy sources). This is called a ketogenic diet.

Should I Get Rid of ALL Sources of Sugar?

Beginning a ketogenic diet (very low carbohydrate and high fat diet) for the purposes of treating your cancer is a decision that requires thoughtful consideration. I don’t believe there is a clear answer on this question yet. There are several clinical trials underway, which you may want to investigate if you find yourself drawn to the ketogenic diet as a treatment option.

Clinical Trials of Keto Diet and Cancer

Cancer Type Being Studied

Reference Number

Glioblastoma NCT01535911



Pancreatic Cancer NCT01419843
Lung Cancer NCT01419587
Metastatic disease of solid tumors NCT0176468
Recurrent glioblastoma NCT00575146
Head and Neck Cancer NCT01975766

Go to to and type in the number in the right column to find out more, or simply search “ketogenic diet and cancer” to see what trials are available.

I would not suggest a ketogenic diet without proper monitoring by your physician and diet planning with your registered dietitian. If you want to know how a ketogenic diet might help you specifically, begin the conversation with your cancer care team.

Are There Dangers to a Keto Diet and Cancer?

In the short term, you may be difficulty concentrating or feel lightheaded or low energy. People also describe a ‘keto flu’ which are flu-like symptoms that are present as your body switches from uses glucose as the main fuel to using fat. Common side effects are constipation and bad breath. Being on keto can also make some social situations difficult as you will not be able to eat all of the food offered.

In addition, there is some evidence that some cancers can experience growth acceleration with ketones. Most notable melanomas with mutated BRAF (Nencioni, 2018)

The Ketogenic Diet is Too Extreme, Are There Other Changes I Could Make?

If you find yourself shying away from the extreme prospect of a ketogenic diet, or its lack of definitive answers, you are not alone. Sticking to these types of diets are a challenge and only due to sheer determination and strength of will are people able to stick to them. Because this diet does not yet have good scientific evidence support it, it’s difficult for me to recommend it at this time.

However, until the clinical trials finish, are published and we have a better idea of the benefits of a ketogenic diet, there are still changes you can make and actions that can be taken!

Cut way back on the amount of nutrient-poor added sugars in your diet. This includes candy, soda pop and other sources of sugar that don’t provide a nutritional benefit to the diet. I will talk more about the amounts in future blogs, but for now, focus on getting these unhealthy sweets out of your diet.

(Want to get access to action-oriented analysis of new clinical trials and studies as they are published? Stay up to date on the latest research, get action-oriented, evidence-based tips and information, and receive thoughtful, researched answers to your burning questions by being part of my Thriving After Cancer Coaching and Support Program, you can join here.)

What is the PET Scan?

PET stands for positron emission tomography (PET). This is an imaging procedure a medical team will use to find exactly where cancer is in your body. Active cells such as malignant cancer cells will use sugar as an energy source at a more rapid rate than normal cells. Inactive cells such as benign cells and scar tissue will not use sugar at the same rate (BC Cancer).

Prior to the scan a patient is injected with Fluorodeoxyglucose (FDG). This is made by combining a special type of sugar with a safe radioactive component to produce what is called a radioactive tracer. Once injected into a vein, the FDG travels throughout the body. Because of their rapid rate of glucose uptake, cancer cells absorb a greater amount of FDG than normal cells. The FDG is then trapped inside the cell. An image is taken of the body and because of its radioactive tracer the FDG appears on the image. The radiologist reading the scan will see the size and location of the cancer.

Does This Mean Sugar Feeds Cancer?

The mechanism of the PET scan is often sighted by proponents of the Sugar Feeds Cancer theory to demonstrate their belief. BUT, the fact is, sugar feeds every cell in the body. However, cancer cells multiply at a much faster rate and therefore, gobble up sugar faster to fuel their growth. This faster uptake of sugar and FDG is what allows radiologists to see cancer on the PET scan.

What Does This Mean For Me as a Cancer Survivor?

One way I can help you as a cancer survivor become a cancer thriver is by helping you reduce your fear. Fear is powerful but it is something you can conquer. If you are afraid of every carbohydrate food—including healthy whole grains, fruits, and legumes—because they convert to sugar, then you are not choosing the best anti-cancer diet, not to mention creating stress hormones because of your fear.

But you can become a cancer thriver by taking action!

Take action to change your diet and lifestyle in a way that will help to reduce your risk of cancer recurrence AND reduce your fear!

To this end, you need to reduce unhealthy sources of sugar in the diet. Cut back on added sugars like table sugar, syrups, soda pop and other sweetened beverages, candies and sweets.

To read about other ways to starve cancer cells, check out Cancer Bites blogs on:

Low Methionine Diet

How to Starve Cancer with Intermittent Fasting


References for Keto Diet and Cancer

BC Cancer. PET Functional Imaging. Accessed July 24, 2020. Copyright 2020.

Nencioni A, Caffa I, Cortellino S, Longo VD. Fasting and cancer: molecular mechanisms and clinical application. Nat Rev Cancer. 2018;18(11):707-719. doi:10.1038/s41568-018-0061-0

Simone BA, Champ CE, Rosenberg AL, et al. Selectively starving cancer cells through dietary manipulation: methods and clinical implications. Future Oncol. 2013;9(7):959-976. doi:10.2217/fon.13.31

Vander Heiden MG, Cantley LC, Thompson CB. Understanding the Warburg effect: the metabolic requirements of cell proliferation. Science. 2009;324(5930):1029-1033. doi:10.1126/science.1160809