Coffee has been shown to boost brain power, decision making, and memory. It also increases your energy level so when you drink caffeine before your workout you can potentially burn more calories. But there are some drawbacks: Caffeine can increase your blood sugar which can work against you if you are trying to lose weight. It can make you feel anxious and jittery. And get this, coffee, vigorous sex (as well as being startled or angry) can increase the incidence of brain aneurysms in people who have already suffered from brain aneurysms in the past.