Why are certain drinks so bad for physical endurance?

I'm pretty big on long distance running and I have a few questions. We all know that drinking alcohol and carbonated beverages in-season is not good for you because it kills your endurance. And I'm not sure, but I think coffee is too? Which of the three...

is the worst for you, and why are they so bad?

Caffeine has several effects on the athlete. Caffeine can improve performance or decrease it. The good things are caffeine is a stimulent, it also increases the amount of fat you can burn and helps preserve muscle glycogen. On the other hand caffeine is a diuretic and can increase denydration.

When i was a competitive bicycle racer I drank coffee or took guarana pills before races or before particularly long or hard training rides. For me it seemed to be a net positive; I seemed to be able to go harder on caffeine than normal. I avoided caffeine for rides when it was over 100F because staying hydrated was hard enough already.

Of course alcohol or sodas in moderation do not kill endurance. You certainly don't want to get drunk since that is injurious and will decrease your endurance for days afterword but enjoying a glass of wine with dinner or a beer after a hard day will not undo your hard work training.

i realy don't know because i drink achol all of the time.