So I read that it is bad to take in less than 1500 calories, no problem - but what burned calories? If I am, say, taking in 2100 cals but I also burn 800 a day am I okay?
So yes, you don't want about 1,500, as you could potentially use a lot less calories, than your body should get, as too many needed calories are burned and sacrificed.
When I say surplus, you need extra calories to burn, so that you don't end up buring ones your body really need, hence why 2,100 is better for you, so you have some Cals ot burn, and your body then has plenty left to use.