What is the least amount of calories you can consume in one day?

The minimum for men is 1500 calories per day.

The minimum for women is 1200 calories per day.

Answer

That's absurd, no offense intended. It all boils down to your lifestyle, and your own body. You would have to visit a doctor to find your minimum calorie intake. If your an athlete training intensely 1500 is no where near enough, while if all you do is sit on your couch and sleep, then quite a bit less. Natural metabolism plays a role in it as well. If your trying to cut calories down to the bare minimum, then for healths sake i would suggest talking to a doctor or dietician, not asking random people online. If you didn't mean safely, then the answer is 0.