Coffee has soooo much caffeine in it that 'less than' would have to be 'a lot less' for it to make any significant difference compared to other beverages--even Mountain Dew.
What really bothered me about coffee/caffeine as a Christian was how it is the legal drug of choice to replace sleep, exercise, and a balanced diet in order to have the motivation and stamina to earn a living. For me there's just something wrong with that. It's so...so...artificial. It reminded me of all the stars and entertainers and musicians that we idolize who rely on the power of their cocaine and other drugs to be great and maintain their talented, energetic, inspired superstar images. That's so phony to me.
The flip side to that is taking sedatives to get the rest they finally realize they do need after bingeing stimulants all their life and then finding out that when they hit their late forties and early fifties you can't drive your body mercilessly forever without it one day refusing to take another step. And for a big mega star trying to maintain their image of greatness, and the payday it brings, that is devastating. So off into the world of sedatives they go, and some kill themselves that way.