“I should also add something about weight here, because we all know that there’s often a relationship between weight and risk for diabetes. If the risk for Alzheimer’s disease goes up with metabolic disorders, then it makes sense that the risk also rises with unhealthy weight gain that has metabolic consequences. The science now speaks to this fact. Carrying extra weight around the abdomen has been shown to be particularly harmful to the brain. One study that garnered lots of media attention looked at over six thousand individuals aged forty to forty-five and measured the size of their bellies between 1964 and 1973.11 A few decades later, they were evaluated to see who had developed dementia and how that related to their waist size at the start of the study. The correlation between risk of dementia and thicker midsections twenty-seven years earlier was remarkable: Those with the highest level of abdominal fat had an increased risk of dementia of almost three-fold in comparison to those with the lowest abdominal weight. There is plenty of evidence that managing your weight now will go a long way toward preventing brain decline later.”