An insider’s perspectives on the Ketogenic Diet

There are a wide variety of dietary recommendations available online, in books, or in practitioners’ offices, with different amounts of carbohydrates, fat, and protein, each purporting to be helpful to people in general and cancer patients especially. I frequently see patients who are completely confused about what they should eat. One unfortunate gentleman even told me that he had become afraid to eat, wondering if everything was poisonous, with detrimental effects on his weight.

My colleague of more than 20 years, the late Dr. Nicholas Gonzalez, and I have treated many patients over the years with nutritional protocols based on the work of William Donald Kelley, D.D.S. Dr. Kelley was a brilliant clinician and observer, who deduced that different patients needed different diets. Depending on their condition and their innate physiology, Dr. Kelley might put one patient on lots of fruits and a wide array of vegetables, along with whole grain products, eggs, dairy, and fish, but no red meat or poultry. Another patient might be told to eat fatty red meat, with lots of butter and root vegetables, but minimal to no fruit, leafy greens, or grains.

The dietary recommendations Dr. Kelley gave to patients were on a spectrum between these two extremes. All diets, though, emphasized the use of unrefined and unprocessed organic foods, and all included some vegetable juice made predominantly from carrots.

For cancer patients, the type of cancer typically correlated to Dr. Kelley’s dietary prescription. Patients with carcinomas (including the most common types of cancer such as lung, breast, colon, prostate) were told to eat a more vegetarian diet, while patients with cancers of the immune system such as leukemias and lymphomas were placed on a higher fat diet.

Different diets: remarkable, documented results

With this system, Dr. Kelley got remarkable results, as detailed in Dr. Gonzalez’ book One Man Alone: An Investigation of Nutrition, Cancer, and William Donald Kelley. Since this was the case, in our work, we continued to give different diets to different people, along with individualized supplement protocols and detoxification routines. And we continued to see remarkable results, as detailed in our published articles and in the books Conquering Cancer, Volume 1 and Volume 2.

Dr. Kelley advised his patients not to eat white flour, white rice, sugar, and other refined products. Such foods, he warned, were empty calories, devoid of the minerals and vitamins needed to process them, stripped of the beneficial fiber that helped maintain a healthy gut. But in the last decade, the phrase “cancer feeds on sugar” has spread wildly online and has been used as a rationale to eliminate not only white sugar and white flour, but also carrots, whole grains, and other foods that had previously been considered healthy.

Dr. Linda Isaacs

Cancer cells get their supply of nutrients from the blood, and it is not physically possible to get the blood sugar low enough to “starve” cancer.

Dr. Linda Isaacs

I believe this is an overreaction. I have patients who have thrived for many years, with cancers that should have killed them long ago, who have been drinking carrot juice and eating fruit and whole grain products the whole time. I have spoken with a patient treated by Dr. Kelley in 1975 for metastatic breast cancer, a condition incurable in orthodox medicine. She is alive and well more than 40 years later while eating a diet rich in carbohydrates. A draconian elimination of carbohydrates was not necessary for any of these patients.

Cancer cells get their supply of nutrients from the blood, and it is not physically possible to get the blood sugar low enough to “starve” cancer. The body fights hard to maintain blood sugar in a narrow range. If a patient eats no carbohydrates whatsoever, the protein in the diet will be turned into glucose; if a patient then eats no protein, the protein in the muscles will be turned into glucose. No matter what a patient does, cancer will still get its glucose.

Advocates of carbohydrate restriction may say that the benefits for cancer come about not by “starving cancer” but rather by preventing the elevation in insulin that is triggered by carbohydrate intake. Insulin spikes can be stimulatory to cell growth; the high sugar load of the Standard American Diet (SAD) causes high levels of insulin, which may lead to insulin resistance and elevated blood sugar (Type 2 Diabetes).

Overweight and obese patients are more likely to have such problems, and these patients should certainly take more care with their carbohydrate intake. But I routinely see new patients who are normal weight, or even underweight, who are terrified of eating a piece of fruit or whole grain bread because it will “feed cancer.” Their relief on being told to eat the fruit is palpable.

Teachings based on clinical observation

One concept I do believe is valuable in the teachings of the ketogenic diet advocates is intermittent fasting, which can be simply managed by not eating between dinner and breakfast the following morning, allowing an 11-12 hour window where no food is taken in. This is more typical of how our ancestors ate and how our bodies were designed to work. The gut uses this window to clean itself out. The Standard American Diet (SAD), which frequently involves an evening sitting in front of a screen munching snack foods, is not healthy.

The ketogenic diet is based on theory, along with studies done in cell cultures or laboratory animals in artificial environments. The cancer patient success stories I have read are unconvincing to me – they are few, short-term, and the patients were frequently combining the treatment with other modalities such as chemotherapy. Since I graduated from medical school, I have seen many treatment methods, orthodox and unorthodox, based on theory, that have not survived the acid test of proper investigation and clinical experience.

To their credit, the high-profile advocates of the ketogenic diet are pursuing such testing. I wish them well, and if they are successful, I will change my recommendations. But in the meantime, I will follow in the footsteps of Dr. Kelley, whose teachings were based on clinical observation, and who had the long-term success stories to back them up. And for you out there who are craving a piece of fruit, I suggest you eat it.

Dr. Linda Isaacs offers nutritional protocols for patients with many different conditions, or for those who wish to maintain their health. Learn more at

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