It caught my attention when three of my running friends or acquaintances suffered early onset Alzheimer’s. All were accomplished endurance athletes with many marathons to their credit. Some researchers think that Alzheimer’s disease is an expression of insulin resistance in the brain, as discussed in this review article “Alzheimer’s Disease is Type 3 Diabetes–Evidence Reviewed.” Mark Bittman, a food writer for the New York Times reports on some of that work in a nontechnical article. In 2012, researchers at Mayo Clinic found a correlation between carbohydrate consumption and early dementia.
When I commented on the three runners I know to Steve Phinney, he pointed to evidence suggesting that high carbohydrate diets combined with vigorous exercise, could contribute to premature aging. That sort of fits with research Robert Lustig cites in “Fat Chance” in the Netherlands. It was found that 1/4 of people who looked lean still had some indications of metabolic syndrome when carefully examined.
Since then, I’ve seen evidence that other neurological disorders could be triggered by high carbohydrate consumption. Conversely, it’s claimed that ketogenic diets may help in treatment of those disorders.
This goes against what I used to think. Before I studied the biology of nutrition, I took that attitude that if you exercised enough, the exercise was more important than diet. Now I think it’s the reverse.