The ketogenic diet, popular at the moment, will not likely prove to be a cure for cancer. The theory appears sound: because cancer cells feed on glucose at a much faster rate than healthy cells (as discovered by Dr. Otto Warburg), it should follow that if you limit carbohydrate intake you will starve off the cancer. However, in practice, that is just not what happens. When Dr. Tom Cowan, a strong advocate of the ketogenic diet, checked the bloods of cancer patients who were following the keto diet to the letter, he found their blood sugar never really dropped below normal. “In no case… did I see a reduction in their tumor burden or objective improvement in their overall condition… theory simply didn’t match up with the reality.” My guess would be that the body automatically regulates blood sugar to where it thinks would be optimal to run its functions. So, if you lower it artificially, it will compensate.
Dr. Linda Isaacs supports this view with specifics: “Having a blood sugar that is too high is definitely bad for you but it’s not actually possible to get it low enough to make a major impact on cancer. So, if you don’t eat any carbs, your body will compensate by taking the protein that you need and turning it into glucose. If you only eat fat,” – I don’t know how you’d do that but let’s say you create the buttered avocados with olive oil diet – “your body will compensate by taking protein out of your muscles to maintain the blood sugar, and once you run out of muscle you’ll just pass out because your brain works on glucose.” Of her patients that reversed cancer, “not one of them did it on a ketogenic diet. They were drinking carrot juice and eating carbs and they seem to have done just fine.”
There is no population on earth who eat a ketogenic diet and have exceptional health and long lifespans. The Inuits, who eat high fat diets, are not in ketosis. And have short lifespans.
 Dr. Cowan, T. (2019) “Cancer and the New Biology of Water”, Chelsea Green Publishing; Ch. 8
This 2018 study found that people who eat low-carb diets have shorter lifespans (four years shorter, on average), unless they eat low-carb vegan diets. Here’s a quote from the conclusion of that study…
“Low carbohydrate dietary patterns favouring animal-derived protein and fat sources, from sources such as lamb, beef, pork, and chicken, were associated with higher mortality, whereas those that favoured plant-derived protein and fat intake, from sources such as vegetables, nuts, peanut butter, and whole-grain breads, were associated with lower mortality…”
Another 2018 study reported that people who ate the lowest-carb diets had a 32% increased risk of death from ANY cause than those eating the highest amount of carbs. The researchers also found that low-carb dieters had a 51% increased risk of dying from heart disease and a 35% increased risk of dying from cancer, compared to people who ate the most carbohydrates.
In 2016, the results of the NUSI metabolic ward study were published, where low carb diets were tested against low-fat diets for weight loss in humans. Gary Taubes and Dr. Peter Attia, the founders of NUSI, are both low-carb promoters and this study was meant to prove that low-carb eating was superior for weight loss, but it actually found that low-fat diets worked better!
A 2011 pilot study involving 16 human patients with advanced cancer concluded that the ketogenic diet “might improve aspects of quality of life and blood parameters,” but the patients did not live longer and none were cured.
This 2012 study showed that tumors can use ketones for fuel. Despite the widespread myth that “cancer cells can’t use fat for fuel,” they most certainly can and do. Many types of cancer cells are metabolically flexible.
In December 2018, a review of ALL published studies using the ketogenic diet for cancer in humans was published. It found that clinical trials using the ketogenic diet for cancer have “largely failed to prove survival prolonging effects.”