There is very substantial evidence that Type 2 Diabetes significantly raises the odds that one will develop Alzheimer’s or other forms of dementia. Here are some presentations:
There is also strong evidence that being overweight or obese raises the odds that one will develop Type 2 diabetes. Here are some articles:
Just being overweight, without diabetes, can still have effects on the brain:
Brains of overweight people look ten years older than those of lean peers
And being overweight together with having diabetes further affects your brain:
Diabetes, weight can combine to alter brain, study says
All the links above have been added to Alzheimer’s > Risk Factors.