1 cup is all I can handle, and I don't drink it each day anyway. I believe the acidity is too high for my system.
If you're drinking too much coffee, you'll especially know when you try to wean yourself away. You'll get withdrawal symptoms like jittery nerves, headaches, and other unpleasant things. The same thing could happen with withdrawal from too much Coca-Cola.
Oh, by the way, I read a book written by a medical professional. Too much coffee works against weight loss. Every time you drink a cup of coffee, you cause insulin to be released, just the same as if you ate a donut. That doesn't happen with tea.