Not eating enough

Hello and welcome to MFP!
If you’re just starting out I’d recommend reading these two threads as they contain good, honest information that will set you on the right track:

http://community.myfitnesspal.com/en/discussion/1235566/so-youre-new-here/p1

http://community.myfitnesspal.com/en/discussion/1080242/a-guide-to-get-you-started-on-your-path-to-sexypants/p1

1000 calories is too low, see the above posts as to why, they'll explain everything.

1000 cals is too little, thats why its telling you that.

I had the mindset that if I was under, it was better. Not true. Your body will go into starvation mode..aka thinking you are storing calories for a reason so you will not lose. You need to eat to lose, as weird as that sounds. I'm still trying to wrap my brain around it too but that's what I keep reading. Just make it healthy choices. Hope that helps