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Breaking Down Food Fads: The Ketogenic Diet

By Margaret Martin, RD, MS, LDN, CDCES April 4, 2018Nutrition Education Services Center Blog

The Ketogenic diet (KD) can be found all over social media, television talk shows, and movie star blogs. An entire industry has popped up around the KD with cookbooks, special “Keto” foods, diet companies, and more. People who have tried the Ketogenic diet claim that it leads to weight loss, changes in blood sugar levels, and decreased hunger. However, the diet is very restrictive which can make it dangerous to follow without the supervision of a doctor and a registered dietitian. Keep reading to learn more about this latest diet craze.

What is the Ketogenic Diet?

The basics of the KD are a revival of food plans like the Atkins diet and those used in Dr. Russell Wilder’s work in epilepsy treatment. The KD severely restricts carbohydrate intake to usually less than 10% of daily calories. (Many health organizations suggest a carbohydrate intake range of 40 to 65% for healthy adults.) The KD is a high-fat and low-protein diet. Fat makes up about 90% of daily calories. Protein only makes up about 5-6%.

What does the Ketogenic diet do to the body?

The KD triggers in the body a state known as ketosis, which means the body turns to breaking down fats instead of carbohydrates for energy. Restricting carbohydrate intake to less than 10% results in the body creating more ketones. Ketones then become the main source of energy for the brain, lungs, muscles, and other parts of the body. The long term effects of this process are not known since most people do not use the diet for over a year.

Are there medical benefits to the Ketogenic diet?

The Ketogenic diet has been used since the early 1900s in the medical treatment of pediatric epilepsy. It’s still used today if other treatments are not successful.

More recently KD research studies are under way for glioblastoma (GBM), a rare type of brain tumor. These patients often use the KD alongside other cancer treatments. The use of the KD in patients requires close medical and nutritional supervision, often testing blood and urine for ketones twice daily at a minimum.

There are also studies in the initial stages for different cancer types. The focus of these studies is often the way some tumors use macronutrients like protein, carbohydrates, and fat to grow. One study involving mice found that some mice implanted with malignant brain tumors showed improvement over time on a KD diet. However, these studies are still in the early stages and more research needs to be done before the findings can be applied to humans or other cancer types.

Is the Ketogenic diet safe for all cancer patients?

The KD puts cancer patients at risk for:

  • Unintentional (dangerous) weight loss
  • Uric acid buildup in the blood which can cause kidney stones
  • Cognitive function changes
  • Stunted growth in pediatric patients

The KD can also pose other challenges for cancer patients. The food variety on the KD is very limited, and it may be expensive and unsustainable over long periods of time. Major food sources of vitamins, minerals and phytonutrients, including probiotics and antioxidants are not allowed or only allowed in small quantities on the KD. For example fruits, most vegetables, legumes (dried beans and peas), and whole grains are not allowed even though these foods are the foundation of a plant-based diet for cancer prevention, heart health, and wellness.

What’s the bottom line?

The KD is not a substitute for cancer treatment such as chemotherapy, radiation, or surgery.

Patients who may benefit from the KD, such as glioblastoma patients, should only begin a KD under the close supervision and guidance of their healthcare team. Currently, the KD is still often used alongside other treatments for these patients.

Be careful not to apply findings from small scale studies done with mice or lab cultures to humans who have cancer. Cancer research often begins in the laboratory, but theories for treatment must be tested through extensive research before trials on humans begin and then studied in clinical trials with large numbers of human participants before the treatment is approved by the Food and Drug Administration (FDA). Additionally, if a treatment works for one specific type of cancer, this does not mean it will work for all types of cancer.

Since reducing carbohydrate intake can help with some medical issues, your healthcare team may suggest a modified KD with more th

an 10% of daily calories from carbohydrate intake in place of the calories from dietary fat. Follow the guidelines your healthcare team provides and ask to speak to a registered dietitian if you have questions.

Always talk to your healthcare team before making any changes to your diet or lifestyle.


Check back on the Pearl of Wisdom blog for future posts in the “Breaking Down Food Fads” series.

Margaret Martin, RD, MS, LDN, CDCES

Author Margaret Martin, RD, MS, LDN, CDCES

Nutrition Educator Margaret Martin is a Licensed Dietitian and Nutritionist in the State of Tennessee as well as a Certified Diabetes Educator. Margaret graduated from the University of Alabama with a Bachelor of Science in Dietetics and received her Master’s Degree in Nutrition Science & Public Health from the University of Tennessee. With more than 10 years of experience in Clinical Nutrition, Margaret has also worked in the insurance industry with WellPoint Inc. and Blue Cross Blue Shield providing telephonic nutrition consultations, service assistance, and web-based nutrition education. In her free time Margaret volunteers with the American Lung Association’s annual “Lung Force Walk" in Middle Tennessee. She belongs to the Oncology Nutrition & Diabetes Care and Education Dietetic Practice Groups of the Academy of Nutrition and Dietetics.

More posts by Margaret Martin, RD, MS, LDN, CDCES

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