"The take home is that regular use of caffeine produces no benefit to alertness, energy, or function. Regular caffeine users are simply staving off caffeine withdrawal with every dose โ using caffeine just to return them to their baseline. "
https://youarenotsosmart.com/2010/02/22/coffee/
I've read this years ago, forgot most of it and became a coffee addict again.
@koos I have read though that caffeine is neuroprotective and moderate regular users of caffeine experience onset and progression of neurodegenerative diseases of age more slowly.
@koos Meta study on caffeine safety came out a couple days ago. Makes some really straightfoward recommendations on how much is safe: "400 mg/day for adults, 300 mg/day for pregnant women, and 2.5 mg/kg/day for children and adolescents" http://www.sciencedirect.com/science/article/pii/S0278691517301709
Of importance maybe that that is less than the 600mg/day from the other study. But also tantalizingly not that far away. 400mg is like 4 cups.