I'm 18 and am soon to start college, I just started the pill, I have a boyfriend and we engage in vaginal intercourse pretty often. Since the pill makes you gain weight, I drink green tea, which is supposed to increase your metabolism (I'm desperate not to gain weight). One cup has about as much caffeine as a cup of coffee and I drink a cup everyday. I also drink alot of coffee. I read somewere that caffeine has a effect on birth control pills, like some antibiotics do. Is this true? If so i want to stop drinking it, please let me know.