Most people who know me would call me the worst possible apostle for effective health management. Suffice it to say that I am not a member of the “my body is a temple” community. I am, however, a strong proponent of using the best tool for any given task—and to state it reductively, your body is the first tool that all other tools rely upon.
This gets into surprisingly difficult issues. I can think of many things that may be good for productivity while being “bad for you:” an afternoon energy shot, a cinnamon bun that lifts your mood, a cigarette, a metric truckload of caffeine. It’s not an either-or situation; some of these might work well for you and also not be the best idea.