First, this is NOT a treatment for Alzheimer's Disease (AD). Rather it is a way to alleviate some of the most critical symptoms - i.e. loss of mental capacity.
The entire basis of the treatment is linked to the fact that the physical changes in the brain caused by AD also make the brain cells (neurons) incapable of using insulin to transport sugar into the cell and the cells cease to function.
However while the cells can no longer use the glucose energy source, they can use ketone bodies for fuel bypassing the metabolic block which prevents them from using glucose.
When AD patients receive high doses of ketones the brain cells arfe no longer starved and begin to work again, sometimes amazingly quickly and well - showing improvements (in the approximately half of the cases where it works) within a few hours.
One way to increase the ketones in the bloodstream is to change to a diet which switches the body's metabolism from running on glucose from carbohydrates to one which burns body fat. Essentially the South Beach Diet.