It's another one of those magic-bullet sort of drinks that promises that you will burn calories drinking it. Basically it has six kinds of caffeine to keep you buzzed for a few hours. I'm not exactly the sort of person who mainlines espresso; I have my one double coffee in the AM, a Diet Coke at lunch and a green tea at about 3. Today I had one Celsius at 9 when I woke up and another one at noon- perhaps I should have eaten in between. I was vibrating like a tuning for for about two hours. I can imagine that a Big Gulp of this would be a carbonated heart attack..