I've just wrapped up the prep phase and worked out around 6 PM. I used Kieffer's PWO shake minus the carbs of course but also w/o caffeine. I only started drinking coffee when I started the prep phase and am still quite sensitive to it – am afraid taking 200-400 mg of caffeine powder at 6 will have me up until 2.On what am I losing out by not having it? The book mentions it 'may' help increase glucose uptake. Any other reasons?? Anyone gradually add it to their evening shake?Thanks,William