Eating exercise calories

I cannot pack away that much extra food. I exercised today, had breakfast, had lunch, and i still have 905 left for the day. Am I really supposed to eat that much food today! Part of my plan is not eating after 7. No way I'm knocking down 900 calories in 3.5 hours...unless I go the cake route which is probably a bad idea.

MFP calculates in your deficit based on your height, age, weight, gender, and goal weight. That deficit is what their calculations say will lead to your desired goal weight in whichever loss increment you selected. Let's say they set you up with a 1,200 calorie deficit. That means that they are recommending that you eat 1,200 calories less than what is needed to maintain your current weight. It's also already adjusted to your calculated Basal Metabolic Rate (how much your body burns through normal daily activity). If, with a 1,200 calorie deficit, you were to eat 1,200 calories with 0 burned from exercise then you would be right on track, but if you burn, say, 800 in exercise, and only eat 1,200 then your net intake is only 400 calories. A prolonged period of eating at that level can trigger survival mode. Survival mode is the point at which your body begins to eat away at it's fat reserves, metabolism is decreased, certain organ functions are decreased, and it becomes harder to lose weight. This also is the beginning of malnourishment, and can lead to serious illness or death.
So, when MFP shows that you have, say, 300 calories remaining it's telling you that in order to reach your net caloric intake goal you need to consume that amount, or you are actually increasing your deficit and running the risk of malnourishment. I can see why people think that it's ok for them not to eat the "exercise" calories, and some people will do just fine in not doing so, but it's recommended that you eat them for good reason. The people here that are eating less than bare minimum calories may lose weight, yes, but they are walking a path as equally unhealthy as overeating. Eating less is good. Not eating enough is bad.
A calorie is a label of energy; specifically the energy required to heat 1g of H20 by 1°C. We are about 60% water on average. Let's analyse what happens to 1g of frozen H20 when we add just 35 calories. It's enough energy to take that 1g of ice and increase its temperature to 35°C which is essentially a hot summer day. That may not seem like much, but it's very important inside the body considering that we generally maintain a core temperature of 37°C. It takes A LOT of energy (calories) to maintain our body systems. That's why it is very important throughout the weight loss process to make sure your getting enough energy. If you're not then you are setting yourself up for failure.

Simple answer: Eat your "exercise calories".