The basic premise is: cancer cells aren’t doing what they are supposed to do, particularly metabolically. If you deprive them of readily available glucose they don’t grow/shrink. More research is needed but it’s not the type that’s likely to get funded since drug companies can’t make money off a diet, especially one like keto. In the Reddit thread there are some good anecdotes about effects seen first-hand on cancer with keto.
Now, the cool thing about all this is: “hedging your bets” is easy: dealing with cancer? there’s nothing stopping you from doing the traditional treatments but also consuming a ketogenic diet. In fact the only drawback I can see in this approach would be that since you are introducing simultaneous variables it will be difficult to determine which is helping more. I’d say that is a good problem to have. I highly doubt an oncologist would balk at eliminating sugar and refined carbohydrates from your diet =)
“The drugs we have now are so toxic and there’s no reason people should have to be poisoned to be healthy. There are a number of studies, including those we’ve published, showing a direct relationship between the ketogenic diet and slowed tumor growth,” says Seyfried, also citing the work of Dr. Valter Longo, of the University of Southern California’s Davis School of Gerontology. That work shows that low-calorie diets are linked with slowed tumor growth and improved response to chemotherapy. “Why spend all this money going after all these different pathways involved in cancer when you can simply go after the key fuels?” Seyfried asks.
Even Seyfried acknowledges, despite his zeal for treating cancer by tinkering with calories, that in all likelihood diet and nutrient-based cancer treatments will serve as adjuncts to existing therapies. But what would be wrong with that? “We’re slowing the tumor down and making it extremely vulnerable to lower, less-toxic doses of available drugs,” he says, “When people are locked into an ideology created by a dogma they tend not to focus on rational alternatives.”