I posted this over in the tips and stalls section.. dont know if you read this or not but hope it helps

"Drinking caffeine in large amounts as coffee over a short period of time has been shown to raise blood sugar. Caffeine does this by enhancing the effect of two hormones (adrenaline and glucagon). These two hormones release stored sugar from the liver resulting in high blood sugar... "

for some people it may cause a stall (although im sure some of you already know that)

LINK to more info

HTH!!!