At a previous programming job I had, we used to regularly have a beer at lunch (in the UK) and it didn't feel like it affected my productivity at the time. This was in my early 20's. I'm now in my early 30's and I find that a beer at lunch just makes me feel tired in the afternoon, so I avoid it.
The point is, it probably affects people in completely different ways depending on physiology, age and health.
The point is, it probably affects people in completely different ways depending on physiology, age and health.