First and foremost, let me say that I am not promoting the Keto Diet Plan as a cure for, or prevention of, cancers. There is no evidence in the research that points to such therapeutic potential on its own. However, the outcomes of recent clinical trials, and substantial scientific basis, suggest a Keto Diet may stress cancer cells and in so doing render them more susceptible to the current standard of care radiation and/or chemotherapy.
It has long been known that a prominent behavior in cancer cells is an increase in the glucose uptake and rate of glycolytic metabolism. The accepted explanation for this was the increased rate of tumor cell growth and energy demands. However recent studies suggest that the increase in glucose uptake may be an adaptation of cancer cells in response to altered cell chemistry that puts the cell under oxidative stress. These stresses are not present in normal cells. In other words, cancer cells don’t need increased glucose metabolism to grow, they need it to remain healthy.
Numerous animal studies over the past 60 years have not only confirmed the observation of increased glucose consumption in cancer cells but also demonstrate the importance of glucose for tumor survival and metastasis.
These findings have launched new studies into dietary modifications that reduce glucose levels and place cells into a state of ketosis in which ketones are burned for fuel instead of glucose. Such a condition not only reduces the glucose available to cancer cells, it also increases the oxidative metabolism that is putting the cells under stress. Such diet based therapies could represent a safe and effective approach to selectively enhance metabolic stress in cancer cells without damaging normal cells .
In a recent paper published by Dr. Bryan Allen, et al. at the National Institutes of Health Center for Biotechnology he writes;
Recently, ketogenic diets have been studied as an adjuvant to cancer therapy in both animal models and human case reports. As early as 1987, Tisdale et al. saw decreased tumor weight and improved cachexia in mice with colon adenocarcinoma xenografts eating a ketogenic diet . Additional studies have shown that ketogenic diets reduce tumor growth and improve survival in animal models of malignant glioma [31–33], colon cancer , gastric cancer , and prostate cancer [36–38]. Furthermore, ketogenic diets have been hypothesized, with some supporting evidence, to potentiate the effects of radiation in malignant glioma models  as well as in non-small cell lung cancer models . Fasting, which also induces a state of ketosis, has been shown to enhance responsiveness to chemotherapy in pre-clinical cancer therapy models as well as possibly ameliorating some of the normal tissue side effects seen with chemotherapy . Fasting cycles are also reported to retard the growth of tumors and sensitize a range of cancer cell types to chemotherapy [40,41].
There are currently eleven (11) clinical trials assessing ketogenic diets as an adjuvant to cancer therapy, including the Univeristy of Wurzberg, Germany, University Hospital in Tubingen Germany, and the University of Iowa. While receiving the standard of care radiation and chemotherapy, patients are consuming a five week ketogenic diet consisting of a 4:1 ratio of fat to carbs + proten with vitamin and mineral supplements. These trails have demonstrated various degrees of improved quality of life, and tumor shrinkage or slowed growth, without adverse events.
Dr. Allen goes on to conclude;
Despite recent advances in chemo-radiation, the prognosis for many cancer patients remains poor, and most current treatments are limited by severe adverse events. Therefore, there is a great need for complimentary approaches that have limited patient toxicity while selectively enhancing therapy responses in cancer versus normal tissues. Ketogenic diets could represent a potential dietary manipulation that could be rapidly implemented for the purpose of exploiting inherent oxidative metabolic differences between cancer cells and normal cells to improve standard therapeutic outcomes by selectively enhancing metabolic oxidative stress in cancer cells.
Although the mechanism by which ketogenic diets demonstrate anticancer effects when combined with standard radio-chemo-therapies has not been fully elucidated, preclinical results have demonstrated the safety and potential efficacy of using ketogenic diets in combination with radio-chemo-therapy to improve responses in murine cancer models. These preclinical studies have provided the impetus for extending the use of ketogenic diets into phase I clinical trials that are currently ongoing.