There is a lot of new research coming together, which suggests that a ketogenic (high fat, low carb) diet is not good for warding off cancer, but it is also good for most other chronic diseases that are major killers, including heart disease, diabetes, and Alzheimer's.
Our typical western grain and carb based diet is a major cause of our poor health. This sort of diet may be "good business", lots of cheap sugary and starchy food with long shelf life, and lots of sick patients to keep the medical and drug companies profitable.
However, there is also evidence that cutting grains and carbs back will give you a better chance of living a long and healthy life. Switching to a high fat (various healthy fats) for one's main energy source, is also a key part to a ketogenic diet. I recently did a short 6 week ketogenic diet and felt quite good on it and lost 4 kilos. I am off it now, but still stick to most elements of the diet.
I encourage you to listen to Dr Mercola interview Travis Christofferson on this topic:
Source: 