Why has my tolerance for coffee gone down?

[Taverner]

I used to drink a pot and a half of coffee per day. Good stuff, the high caffeine dark roasted Allan Brothers/Peets stuff.

Now I'm lucky if I can drink a second cup without getting jittery and dizzy. What gives???

[LaraMN]

1. I thought I was o.d.ing on caffeine, due to taking headache meds

constantly. Then I realized I was really only ingesting the equivalent of two or three cups of coffee over the course of a couple doses. I get jittery if I have caffeine on an empty stomach. Are you eating enough?

[Taverner]

2. I am - this morning I had a protein smoothie (with fruit), uncle sam cereal

And two mugs of coffee - now I'm dizzy and a little nauseous

[SouthoftheBorderPaul]

3. I've had the opposite experience.

Caffeine used to be my best friend, my closest ally. Father, mother, secret lover. It was sun and it was moon. God and man. Earth, Wind and Fire. Paper and plastic. But caffeine betrayed me taking all its buzzy goodness away, and leaving me groggy every morning despite imbibing countless cups of hot, tasty coffee. So, good riddance, coffee, and HELLO RITALIN!!!