I drink a couple monsters a day and don't have issues eating. A smoke cigs as well and can put down 3000 Cal's a day (I'm a small Guy so 3000 is sufficient to build muscle)
For some people it makes no difference, I was drinking 8 tins of emerge (cheap redbull) a day at one point, once I kicked that habit my appetite rose at least 1000 cals a day, though that's just me