Keto for Cancer: A Science-Based Guide
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Keto for Cancer: A Science-Based Guide

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Keto for Cancer: A Science-Based Guide

Posted 2 years ago

Brian Stanton

Brian Stanton


Dr. Kevin R. Gendreau

Dr. Kevin R. Gendreau

Author and Scientific Reviewer

Expert Approved

In 2020, cancer killed almost 10 million people worldwide. That’s about 1 in 6 deaths.[*

In the US alone, clinicians diagnose about 1.8 million new cases every year. Accordingly, national cancer care costs now exceed $150 billion annually.[*

To fight this scourge, researchers are studying a variety of anti-cancer interventions. One of the more promising (and safer) interventions is the ketogenic diet

Curious to find out what’s known about Keto for cancer? Keep reading.

What Is The Keto Diet?

The ketogenic diet (Keto diet) is a very low-carb eating plan. When you eat Keto, you generally keep carbs below 5 or 10 percent of daily calories. 

Keeping carbs low suppresses blood sugar and insulin levels, signaling your liver to burn fat and make ketones.[*] This fat-burning metabolic state is called ketosis.  

How Might Keto Help With Cancer?

To understand how Keto fights cancer, you need to understand the Warburg Effect. Discovered by Otto Warburg in the 1920s, the Warburg Effect describes the tendency of cancer cells to prefer glucose over oxygen as fuel.[*

Think of cancer cells as glucose-hungry pests. Fueled by sugar, they thrive in low-oxygen environments and aggregate into tumors. 

That’s where Keto comes in. On Keto, instead of mainly burning glucose (sugar) for energy, your cells start burning fat and ketones.[*]  

Cancer cells don’t like this metabolic switch. They love glucose, remember? So when it’s not available, they starve. 

But blood glucose suppression is just one piece of the Keto-for-cancer puzzle. Let’s review two other mechanisms by which Keto may help. 

#1: Anti-cancer ketones

Cancerous cells are deranged versions of healthy cells. Deranged how? For one, their cellular power plants (called mitochondria) don’t work correctly. 

Specifically, tumors can’t effectively metabolize ketones. Healthy cells can, but cancer cells can’t.[*

Ketones also serve as signaling molecules that activate anti-inflammatory pathways. Activating these pathways (like NRF2) appears to have a tumor-suppressive effect in animal models.[*]  

#2: Less oxidative stress

When cells burn glucose, they belch up byproducts called reactive oxygen species (ROS). These molecules cause damage and inflammation, which is just what tumors like. 

But when cells burn ketones, they create fewer ROS. This explains, researchers believe, why mice with brain cancer live longer on Keto.[*]

Yet cancer is a tricky beast. Some cancers suppress oxidative stress, allowing the tumor to flourish in a low-oxygen environment. Here too, Keto may help by sensitizing the cancer to other therapies.[*

Common Keto for Cancer Questions

You probably have lingering questions about Keto and cancer. Let’s see if we can answer them. 

Is there clinical evidence supporting Keto for cancer?

Most of the data are pre-clinical (in animals), but there’s clinical evidence too, mostly case reports and small trials.[*] Many studies are “feasibility studies,” meaning they examine the safety and tolerability of Keto (not mortality outcomes) for people with cancer. 

Here are several examples[*].

  • Women with endometrial or ovarian cancer had decreased IGF-1 (a pro-cancer marker) and increased energy after three months of Keto dieting. 
  • In twenty glioblastoma patients (no control group), being in ketosis was linked to increased progression-free survival.[*
  • Keto dieters with pancreato-biliary cancer had more energy and satisfaction after surgery.
  • Several studies showed that Keto helped maintain body composition (retain muscle) in cancer patients. Preventing weakness and muscle loss in cancer patients is important; these individuals need to be as strong as possible to survive.

The research continues, so stay tuned.  

Is Keto beneficial for all cancers? 

Probably not. While certain cancers—breast cancer, brain cancer, colon cancer, etc.—seem to be deterred by Keto (in mice, at least), others aren’t.[*]

In one study, mice with melanoma showed increased tumor progression on a Keto diet. In other studies on kidney cancer, Keto mice had decreased survival rates.[*]

The “why” is unclear. What is clear is that we have lots to learn about Keto and cancer.  

Can a Keto diet prevent cancer?

To properly answer this question, we’d need long-term studies following Keto dieters for decades. We don’t have those. 

But the animal evidence is promising. In general, mice fed Keto diets develop less cancer than mice fed standard chow.[*

Should Keto be a standalone or adjuvant cancer therapy?

No foremost cancer authorities currently recommend a Keto diet as a standalone treatment for cancer. The standard of care generally involves surgery, chemotherapy, radiation, and other modalities. 

That said, Keto is a low-risk intervention. And the existing data suggests that Keto may effectively complement standard therapies.[*] (Human trials often feature Keto as adjuvant therapy). 

The takeaway? We should consider Keto an adjuvant (and perhaps preventative) therapy, but probably not a standalone treatment. 

Potential Downsides of Going Keto

Done correctly, Keto is a safe and well-tolerated diet. It’s the “doing it correctly” part that’s difficult. 

The hardest part is staying in therapeutic ketosis. Most people can have a few carbs on Keto and still achieve weight loss or energy goals. But the macronutrient ratios aren’t as flexible on a therapeutic Keto diet. 

And so compliance is the big hairy challenge in Keto for cancer research. Proper guidance and supervision help, but many people can’t stick with a strict Keto diet. 

Other potential risks include headaches, fatigue, cramps, and other “Keto flu” symptoms, but you can generally mitigate these risks with proper planning. For example, taking more electrolytes often solves the symptoms rather neatly.

Next Steps

If you want to try Keto as part of your cancer treatment plan, first talk to your doctor. You don’t need their permission to change your diet, but it would be preferable to get them on board and understand how Keto may complement your existing treatment regimen. Perhaps send them this review paper to get their gears turning. 

Next, form an action plan. Carb Manager can help with macro tracking tech, community support, and a boatload of how-to guides, but ultimately, the planning and execution will be up to you. 

For a more structured approach, you might also consider enrolling in a clinical study. Check to see if you’re eligible for any studies on Keto for cancer.  

As you embark on your Keto journey, continue to monitor subjective and objective biomarkers like energy levels, sleep, muscle mass, and bloodwork. Keep tracking, keep tinkering, and stay positive.