A ketogenic diet may have health benefits for the treatment or prevention of cancer. But research is mixed, and it can have downsides for people receiving ongoing cancer treatment.
Cancer is most commonly treated with a combination of surgery, chemotherapy, and radiation. Many different diet strategies have been studied, but none has been particularly effective.
Some early research suggests that a very low carb ketogenic diet may help.
Important noteYou should never delay or avoid conventional medical treatment of cancer in favor of an alternative treatment such as the ketogenic diet. You should discuss all treatment options with your healthcare team.
One factor contributing to cancer cell growth is carbohydrates or blood sugar. Your body breaks down carbs into glucose, a sugar, to provide energy to all cells, including cancer cells.
A ketogenic diet alters some of your metabolic processes, and your blood sugar levels decrease. Basically, this is claimed to “starve” the cancer cells of some fuel and cause them to:
- grow more slowly
- decrease in size
Contrary to the common myth, cancer cells can still grow on fats and amino acids, so going sugar-free won’t stop their growth or kill them, but it may reduce it.
The ketogenic diet involves restricting carb intake. Reducing carbs lowers calorie intake, reducing the energy available to the cells in your body.
This may slow tumor growth and the cancer’s progression. Other possible benefits of the ketogenic diet for cancer may include:
- Lowered insulin: When present, insulin makes cells, including cancerous cells, grow. Lower insulin levels may slow tumor growth.
- Increased ketones: Cancer cells can’t use ketones as fuel. Animal research shows that ketones
may reduce tumor growth.
One study from 2019 shows a ketogenic diet may reduce tumor growth and improve survival rates.
Specifically, it found that using a low carb diet to restrict glucose levels prevented the growth of squamous cell carcinoma tumors in mice with lung or esophageal cancer. The mice received only 0.1% of their calories from carbs.
The diet was even more effective at preventing tumor growth when it was combined with the diabetes medication canagliflozin.
The ketogenic diet alone didn’t shrink existing tumors, and neither did the chemotherapy drug cisplatin. However, combining these 2 methods was effective at helping shrink tumors.
In some cases, the ketogenic diet made the anticancer drugs phosphoinositide 3-kinase inhibitors (PI3K inhibitors)
Despite the promising evidence in animals, human research is only just emerging and is largely limited to case studies.
Limited research seems to show that a ketogenic diet may reduce tumor size and the progression rate of certain cancers.
Brain cancer studies
Much of the research on cancer looks at glioblastomas, which are particularly aggressive brain tumors.
A 2010 case study marked the first time that research was published on the effects of treating a glioblastoma with a combination of standard therapy and a restricted ketogenic diet.
The case study followed a 65-year-old woman. After surgery, she followed a very low calorie ketogenic diet. During this time, the
However, 10 weeks after returning to a regular diet, she experienced a significant increase in tumor growth.
Similar case reports from 1995 examined the reactions to a ketogenic diet in 2 girls who were undergoing treatment for advanced brain cancer. Researchers found that glucose uptake was decreased in the tumors of both girls.
One of the girls reported
More recently, a 2018 study found that the ketogenic diet is safe and may help enhance the effects of traditional cancer treatments.
Studies of other cancers
Following a ketogenic diet for 12 weeks significantly increased the physical function of women with ovarian or endometrial cancer in a 2018 randomized, controlled trial.
Some participants in the study followed the high fiber, low fat American Cancer Society diet instead.
The women who followed the ketogenic diet were more likely to report that they could complete activities such as climbing stairs or moving a table. They also experienced other benefits, such as:
- increased energy
- decreased cravings for starchy foods and “fast food fats” like pizza.
The ketogenic diet may also improve the body composition of people with various types of cancer.
In a 2020 study of 81 people, researchers observed benefits such as reduced fat mass in people with rectal or breast cancer and preserved skeletal muscle mass.
Study participants experienced these benefits while receiving radiation therapy, chemotherapy, or a combination. These standard cancer treatments have been known to negatively affect body composition and appetite.
Quality-of-life study
One 2020 quality-of-life randomized, controlled clinical trial investigated the effects of a ketogenic diet on 80 people with advanced or metastatic breast cancer and without a history of kidney disease or diabetes.
Participants were assigned to either a ketogenic diet group or a control group who didn’t follow a diet. After 12 weeks, the quality of life between the groups
However, the ketogenic diet group showed a better global quality of life at week 6 than the control group.
A ketogenic diet may help prevent the development of cancer. It may reduce several of the main risk factors.
May decrease IGF-1 levels
Insulin-like growth factor 1 (IGF-1) is a hormone important for cell development and reducing programmed cell death. This hormone also plays a role in the progression and metastasis of cancer.
A 2024 study of a 21-day ketogenic diet found that it may lower IGF-1 levels, decreasing insulin’s direct effects on cell growth. This may reduce tumor growth and cancer risk over the long term.
Can help blood sugar levels and management of diabetes
Other evidence suggests that people with diabetes have an increased risk of developing certain cancers, including:
- hepatocellular carcinoma
- pancreatic cancer
- endometrial cancer
- colon cancer
- rectal cancer
- breast cancer
- bladder cancer
Research from 2019 shows that a ketogenic diet may be effective at lowering blood sugar levels and managing diabetes in the short term.
Some people may find it challenging to adhere to the diet for a long period of time, though. More studies on the diet’s long-term safety are needed.
May decrease obesity
A 2023 cohort study of 2.6 million Catalan adults found that having obesity during early adulthood is a
Since a ketogenic diet is a powerful weight loss tool, it may also help reduce the risk of cancer by preventing or reducing obesity.
No experts recommend the ketogenic diet for either cancer prevention or cancer treatment, despite the promising research.
The ketogenic diet may have some benefits, but it comes with risks, too:
- High in fat: Many high fat foods allowed on the diet, such as red meat, have been shown to
increase the risk of some cancers. - Restrictive: The diet limits foods known to prevent cancer, such as whole grains, fruits, and some vegetables.
- May cause weight loss: It can be challenging for those undergoing traditional cancer therapies to consume enough calories while on the diet. Low carb diets often result in weight loss.
- Low compliance: The restrictive nature of this diet can sometimes be too much for a person with cancer, especially when food can be a source of comfort.
The ketogenic diet isn’t appropriate for everyone and could even cause harm.
If you’d like to explore the ketogenic diet for cancer, speak with your healthcare team or a registered dietitian first. They can help you decide whether it’s right for you and work with you throughout the process.
A ketogenic diet provides many health benefits. According to animal studies and human research, it may treat or prevent cancer. However, it’s important to remember that research is still emerging.
You should not avoid conventional cancer treatment in favor of an alternative treatment like the ketogenic diet. Follow the advice of your oncologist. Mainstream medical treatments effectively treat many types of cancer.
A ketogenic diet could be a good adjuvant therapy, meaning that it’s used in addition to conventional treatments. Speak with your oncologist or a registered dietitian to try this diet.
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