Although it is often associated with the high-protein Atkins diet, ketogenic diets are useful for more than just weight control. These are classified by their very low carbohydrate content, low enough to push the body’s metabolism into using ketones, which are breakdown products of fats, for energy. One other purpose of the ketogenic diet is as a cancer treatment, often alongside other conventional and/or natural therapies.
The story of Elaine Cantin is an example of this, who began to research and modify the ketogenic diet to suit her own needs after seeing too many loved ones die after chemo and radiation. Eventually, her cancer was gone, but this diet is still hidden from most of the general public in obscurity.
So what other evidence is there to support the ketogenic diet as a cancer treatment? Multiple studies on mice have shown that this diet can dramatically slow and possibly reverse tumor growth, with in vitro research finding that, besides sugar deprivation, ketone bodies have direct antitumor effects.
For example, in one study, mice on low-calorie ketogenic diets had tumors that were 48% lower in weight than controls; those also on the glucose inhibitor known as 2-deoxy-d-glucose saw an 80% reduction in tumor weight compared to controls. 
In another, mice on the “KetoCal” diet saw slowed tumor growth, decreased blood vessel growth, and increased survival, with mice on the calorie-restricted version surviving the longest. Tumor density had also been significantly reduced. 
In a human study, 297 patients who had undergone resection surgery for glioblastoma were examined for hyperglycaemia (high blood sugar) in relation to survival time. Besides age and higher tumor grade, administration of corticosteroids and the chemo drug Temodar were also associated with lower survival time. 
Persistent hyperglycaemia, the exact opposite of the ketogenic diet’s effect, was defined as at least 3 measurements of blood glucose yielding a result of over 180mg/dL in 1-3 months after surgery. Hyperglycaemic patients were found to have a survival time of 5 months as opposed to 11 months on average; the recurrence group also had a survival time of 5 months instead of 9 months. Patients without recurrences had average survival times of 8 months with hyperglycaemia and 13 months with normal blood sugar levels. 
A similar study on 191 people also undergoing radiation found that those with blood glucose levels of under 94mg/dL, 94-109mg/dL, 110-137mg/dl and over 137mg/dL had median survival times of 14.5, 11.6, 11.6 and 9.1 months respectively. 
In fact, a meta-analysis, the highest “level” of quality that research articles can be, involving 20 papers and totaling over 13,000 patients found that metformin increases survival rates in cancer patients – because of its ability to reduce blood sugar levels. Other research on the ketogenic diet specifically found enhanced quality of life in patients who stayed on this diet, although it differed from what Elaine Cantin used to heal herself, as it contained dairy products. 
One very important benefit of a ketogenic diet, in relation to quality of life and often even survival, is the prevention of cachexia. This is a vile, insidious condition where muscle and fat are degraded and appetite is obliterated, which is also responsible for around 20% of all cancer related deaths.
Ketone bodies have been found, fortunately, to protect against the pro-cachexia metabolic changes, reduce glutamine (an amino acid important for cell growth) uptake and reduce energy production in pancreatic cancer cells. They also inhibited glucose uptake into cancer cells, caused some of the cancer cells to kill themselves, and protected against muscle and fat breakdown.
While more research on humans is needed, especially with the Cantin version, the ketogenic diet seems promising, and although it may seem restrictive and unpleasant due to the limits on carbohydrate intake, a wide variety of recipes can be found throughout the web.