With all the research into dementia and its causes, if there was a simple strong link to overweight I can't imagine that would not stand out in the data and be well known by now.

Edit: although, there are well-known links between overweight and a lot of negative outcomes, and yet people are still too fat.

Nearly 75% of Americans are overweight. (over 30% 'overweight', over 40% 'obese').

Obviously, 75% of Americans do not develop dementia. Do more who are overweight develop dementia than those who are not? Well...it's hard to say when 3/4ths of the population is overweight.

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