More than four million Americans have the illness. By 2040, that number is expected to double. It's Alzheimer's disease.
Now a new study says what you eat and overeating could increase your risk of getting the disease, but only if you carry the Alzheimer's gene.
Some researchers beleive restricting calories may slow the body's production of the aging process by reducing the production of cell-damaging oxygen molecules that form when the body breaks down food.