do you eat exercise calories?

I always eat them otherwise Id be below my minimum amount of calories. I think you definitely need to eat them back if you already eat a low amount of calories eg 1200 per day.

First off, I would make sure you are eating above your BMR and not just going with the 1200 minimum. Then if I am eating close to BMR, I would eat back most of them back but if I'm a ways above BMR but still well under TDEE I would only eat about half back. MFP tends to over estimate caloric burn and even if you use a heart rate monitor it's still not an exact number.

No. I leave the calorie deficit

Then you are creating a HUGE calorie deficit.

Your daily goal at MFP has you at a deficit before exercise - meaning you can eat TO GOAL every day, do zero exercise, and you'll lose weight. Burning off more cals through exercise increases the deficit - generally leaving you with too few calories which can cause you all sorts of problems in the long run.

This is why your exercise cals are added back into your goal - you are supposed to eat them back. Your NET cals should be at or near goal at the end of the day.

A small deficit is best for fat loss. It may seem like fewer cals and a larger deficit would speed things along, and you might lose a little bit faster, but you risk losing a lot of lean body mass along with the fat, which is no good, as well as ending up under-fueled, hungry, angry/grouchy (commonly known around here as "hangry"! ), no energy for workouts, and eventual burn out.

MFP is a fabulous tool and works well when used correctly.

Eat your cals, drink water, exercise, take rest days, get good sleep, have patience. Good luck.

I eat some of them, especially when I have an intense workout that burns 700 or more calories. ( In a 90 minute period ) Usually the more I exercise I add a couple hundred more calories to my day. I try to eat 1400-1600 on more active days.

I found that burning 700-1000 calories per day and eating 1200-1300 was a little low for the activity level. If I am lightly active or sedentary I will stay in that range though.