I have done this before when doing a cutting/lean mass type of cycle. I will start out that way and try to stick to it for at least a few weeks and see what happens. Usually my bodyweight will stay the same but I will see myself getting leaner. I measure my waist line and I can see the inches dropping. I do usually add a bit of protein in later in the cycle to supplement more growth while keeping track of my fat levels by measuring my waist. If my waist size grows then I know its time to cut back. If you are trying to put on mass I wouldnt reccomend keeping calories the same, but if youre looking to cut it is a very slow way to lose fat.