Eating your exercise calories?

OK....you tell MFP your height, weight, etc along with how much you want to lose per week. They figure out how many calories you need, then they knock 250 calories MINIMUM off that to get how many calories you need to eat to lose X amount a week (in my case it is 500 cal for 1lb a week).

if you exercise MORE than MFP expect you to, and you don't eat your calories back, you run the risk of your body trying to hold onto calories because it isn't sure when you are going to get more. You also might feel weak, tired, dizzy, etc. You really should not net less than 1200 calories on a regular basis unless you are under medical supervision.

ETA: so if you eat 1200 calories a day, then exercise off 600, you are only giving your body 600 calories to function on--basically to keep you alive. I am 5'2" and 204lbs, my body requires a little over 1500 calories to do this. I assume you wouldn't dream of ONLY eating 600-800 calories a day, every day, so why essentially do that?

If you eat 1200 calories a day and work off 200 of them, I don't see why you'd want to re-eat them? Personally, I feel like I've accomplished something and I don't want to eat them back. You're supposed to be at a calorie deficit to lose weight (3500 = 1 pound). I wouldn't go overboard and burn 1500 and only eat 1200, but if you feel energetic and still functioning, I wouldn't overthink it. I've always eaten around 1200 calories (usually 100 under) and now that I work out, I find that I'm hungrier, so I'll eat 1200 or 1250 or so. Listen to your body. Except when it tells you to eat a lot of cake!

because BMR is what your body requires to do things like breathe and make your heart beat...most peoples BMR is in the 1500+ range, and MFP calculates energy needs based on activity, then creates a deficit. When you eat below THAT, you tend to create issues, like slowing weight loss 'cause your body is not sure when it will get adequate fuel...