"Seriously Pritikin is the way to go. Brain burns carbs through glycolysis much cleaner than protein or fat. Exercise burns off the fat and protein away from the brain and helps keep the brain healthy. Excess iron buildup in organs can be problematic as we age. Gains from a high red meat& fat diet are only temporary and you will pay later."
This the problem that ronstern refers to. Pritikin may suit some people. It doesn't suit others. There is evidence that low saturated fat diets are a factor in depression (see mazwegian's post above), and Pritikin himself committed suicide, probably because his diet had failed to cure his cancer.
When talking about diets you must never say definitive terms. Will, must, etc. have to be replaced by may and might, as there are always many exceptions to the "rule". For instance, my uncle had a high junk meat, high fat, high processed bread diet, very low on fruit and vegetables, yet lived to 97, totally compos mentis until a few months before his death, and pretty fit (a handshake like the Jaws of Life).
