Do Bulletproof Coffee Really Affect Your Body?

"I don't drink alcohol or smoke and I rarely drink caffeine," he says. "When I do, if I drink it on an empty stomach, I am like about, I literally want to throw up." Caffeine puts you in a heightened state of performance that's very quickly followed by a crash. The same thing is happening with caffeine and sugar as well: You get jittery and anxious and sweating sometimes.