You can count them if you want to watch calorie intake and if you want to reach a certain level of calories so your body gets the right nutrients and use to the intakes , I never got too fancy with that since I eat healthy enough and only watch my self with greasy foods, sugars and such. junk food i only eat like a few times a month can't help my self.
Yeah those fit bit work well, it should give you a general idea of how much your body can handle and when to stop, also dont over do it