Ketogenic Diet and Breast Cancer: What the Research Says

Ketogenic Diet and Breast Cancer: What the Research Says- The ketogenic diet (often called the “keto diet”) is a high-fat, very low-carbohydrate eating plan designed to shift the body into a metabolic state called ketosis, where fat is used for energy instead of glucose.

Because many cancer cells rely heavily on glucose to fuel growth, researchers have explored whether lowering blood sugar and insulin through a ketogenic diet might help slow tumor growth or improve treatment response.

For people diagnosed with breast cancer, the ketogenic diet is still considered experimental, but a growing body of research is exploring its potential benefits and risks.

There is an ongoing debate about the cancer patient’s diet as a possible complementary therapy to whatever conventional therapies the patient is also undergoing. Does diet matter? If so, which diet?

Anti-angiogenic?
Vegetarian?
Vegan?

As a long-term cancer survivor, my meaning of the question, “does it matter?” means several things. First and foremost, when I ask if a diet matters when talking about surviving cancer, I mean does the cancer patient live longer, on average, when living on the diet in question? Secondly, does the diet supply the patient with the necessary protein, carbs, fiber, etc? And lastly, is the diet clean aka without pesticides, etc.

Below are three diets that are often included in the diet debate among cancer patients.

The study linked below finds that, on average, cancer patients live longer when living on a ketogenic diet. I linked the video below because Dr. Tom Seyfried talks about the same concepts that the study below does.

Can a keto diet eliminate cancer growth? Dr. Thomas Seyfried says yes

To complicate things a bit, I have often posted on PeopleBeatingCancer.org about the gut microbiome and its effect on chemotherapies and immunotherapy. I don’t know what a ketogenic diet does to the cancer patient’s gut microbiome.

Further, please pay strict attention to the study below when it states:

“However, long-term adherence showed large differences, with dropout rates ranging from 20% to over 50% in some trials. Factors contributing to non-adherence to ketogenic diets included taste fatigue, gastrointestinal symptoms such as nausea and constipation, and the restrictive nature of dietary protocols.”

As almost every dieter knows, sticking to any diet can be difficult. Be honest with yourself about your ability to stick to the rigors of a ketogenic diet before you begin. If your goal is to enhance the efficacy of treatment while reducing treatment side effects, consider learning more about:

This is just me but if I were a newly diagnosed cancer patient about to undergo induction therapy of some kind, I would focus on prehabilitation. I would find a local clinic to administer intravenous vitamin C therapy to me, I would exercise each day moderately, get plenty of sleep, and eat a diet shown to enhance my gut microbiome. Because chemotherapy and antibiotics have been shown to disrupt the gut microbiome, I would work to eat yogurt, fruits and veggies, etc., regularly. I might even snack a bit on dark chocolate.

Please scroll down the page and post a question or comment. I will reply to you ASAP.

David Emerson

Cancer Survivor
Cancer Coach
Director PeopleBeatingCancer

Why Researchers Study the Ketogenic Diet in Breast Cancer

Breast cancer cells often show altered metabolism, sometimes called the “Warburg effect.” These cancer cells rely heavily on glucose for energy.

A ketogenic diet dramatically reduces carbohydrate intake, which may:

Lower blood glucose levels
Reduce insulin and insulin-like growth factor signaling
Increase circulating ketone bodies
Shift the body’s metabolic environment

Some researchers believe these changes may create conditions that are less favorable for cancer growth.

Preclinical research has shown that ketogenic diets may slow tumor growth, delay tumor development, and extend survival in animal models.

Human Research on Ketogenic Diet and Breast Cancer

Clinical studies are still small, but several have explored how ketogenic diets affect breast cancer patients.

1. Randomized Clinical Trial During Chemotherapy

A randomized controlled trial examined ketogenic metabolic therapy in women with locally advanced or metastatic breast cancer undergoing chemotherapy.

Researchers found that patients on the ketogenic diet experienced:

Reduced insulin levels
Lower inflammatory cytokines (such as TNF-α)
Increased anti-inflammatory IL-10
Possible improvements in tumor response

The authors concluded the ketogenic diet may improve metabolic and inflammatory markers and potentially support treatment response, although more research is needed.
https://pubmed.ncbi.nlm.nih.gov/32703721/

2. Ketogenic Diet Combined With Hormone Therapy

An early clinical trial is exploring whether a ketogenic diet combined with the drug letrozole may improve outcomes for estrogen-receptor positive breast cancer.

Researchers hypothesize that reducing insulin and metabolic signaling may help slow cancer growth.
https://www.cancer.gov/research/participate/clinical-trials-search/v?id=NCI-2019-03071

3. Ketogenic Diet May Improve Response to Targeted Therapy

Laboratory research suggests ketogenic diets may enhance response to certain targeted therapies such as Fulvestrant in metastatic breast cancer.

This suggests ketogenic metabolic changes might make tumors more vulnerable to treatment.

Potential Benefits for Breast Cancer Patients

Some proposed benefits of ketogenic metabolic therapy include:

Lower Insulin and Blood Sugar

High insulin levels are associated with worse outcomes in several cancers. Keto diets can significantly reduce insulin levels.

Reduced Inflammation

Clinical studies show decreases in inflammatory markers in breast cancer patients following ketogenic diets.

Possible Improved Treatment Response

Metabolic changes may make tumor cells more sensitive to chemotherapy, endocrine therapy, or targeted therapy.

Weight Loss and Metabolic Health

Obesity and metabolic syndrome increase breast cancer risk and recurrence risk.

Ketogenic diets often produce rapid weight loss and improved metabolic markers, which may benefit some patients.

Possible Risks or Concerns

While some evidence is promising, ketogenic diets are not universally beneficial for all cancers.

High Fat Intake May Fuel Some Tumors

Research suggests high levels of circulating fatty acids may promote tumor growth in some breast cancers.

Potential Increased Metastasis in Animal Studies

A mouse study reported increased lung metastases in breast cancer models fed ketogenic diets.

Nutritional Deficiencies

Strict ketogenic diets can be low in:

Fiber
Phytochemicals
Certain vitamins and minerals

These nutrients are often abundant in plant-rich anti-cancer diets.

Bottom Line

The ketogenic diet remains a promising but experimental metabolic therapy in breast cancer.

Current evidence suggests it may:

Improve metabolic markers
Reduce inflammation
Potentially enhance some treatments

However:

Results are inconsistent
Long-term safety is unclear
Benefits likely vary by tumor type and patient metabolism

Most oncology researchers recommend using ketogenic diets only under medical supervision, ideally within clinical trials or integrative oncology programs.

Research Citations

The Effect of a Ketogenic Diet on Cancer: Evidence From Systematic Reviews and Meta-Analyses

Background:

Emerging evidence suggests that the ketogenic diet (KD) may support cancer treatment by improving metabolic parameters and reducing treatment-related side effects. This review aimed to synthesize evidence from systematic reviews and meta-analyses on the effects of ketogenic diets in cancer, focusing on metabolic outcomes, body composition, quality of life, and tumor progression. Treatment-related complications were considered as exploratory outcomes.

Methods:

A comprehensive review of meta-analyses were conducted following PRISMA guidelines. Databases including PubMed, Scopus, and Web of Science were searched for systematic reviews and meta-analyses exploring the effects of KD on cancer and treatment side effects. After screening 615 articles, 24 eligible reviews were examined to explore the effects of ketogenic diets on metabolism, quality of life, body composition, and cancer progression.

Results:

KD improved metabolic markers such as glucose and triglycerides, and showed benefits in body composition and quality of life. Evidence on treatment-related complications, including radiotherapy side effects, was limited and heterogeneous.

Conclusions:

KD shows promise as a safe and effective adjunctive therapy in cancer management. More evidence is needed to draw firm conclusions.

To Learn More About Complementary Therapies

Healthy Microbiome Nutrition–

Supplementation for Cancer Patients

Exercise as cancer therapy

Acupuncture and Side Effects-

10 Mind-Body Therapies Better than Chemo

Ketogenic Diet and Breast Cancer: What the Research Says Ketogenic Diet and Breast Cancer: What the Research Says Ketogenic Diet and Breast Cancer: What the Research Says