Questionable Math

You only ate 800 calories? As a guy, you should never go lower than 1200-1400.

Your diary says that you got 2500+ calories from exercise. I would LOVE to know what you are doing! I would love calorie burns like that!!!!

Right now, at my pace, I would have to work out at FULL intensity for 4 hours to get a burn like that.

You will find a lot of different answers from people on whether or not you should eat back your exercise calories. But I'll tell you one thing...you should definitely be eating more than 819 cals in a day. Go to "Search" in these topics and look up "starvation mode". Hope this helps. And welcome to MFP!

My husband had the same questions when he first started this. He couldn't believe that he was suppose to eat that much. I will tell you the same thing I told him. Give it a month. If you don't see the results you want then do it your way. 50lbs later he is loving it and enjoying torturing me with all the extra calories he has after a 7 mile run

Side note - If you are only eating 800 caloriesa day your body is going to get very angry with you and cause weight gain instead of loss.

Yes. That is how it works.

The site sets you up with a calorie deficit. This deficit is based on your week goal. So if you want to lose a pound a week (the BEST way in my opinion) it figures out how many calories you need to live with no exercise then it subtracts 500 calories (500 x 7 days a week = 3500 calories which supposed = 1 pound).

When you exercise you burn more than what the site originally calculated so it tells you to eat more. If you don't eat what you burn your deficit becomes larger than 500 calories.

This might lead to "starvation" mode (although some believe that's a myth). More importantly to me anyway, is that this becomes too hard and you become less likely to stick with it. Finally if you do reach your goal this way it becomes difficult to return to normal eating which might lead to regaining the weight.

You should be eating what MFP suggests to lose you goal amount of weight. You daily goal, plus eat back what you burned.

How are you calculating calories burned?
If you are not using a HRM I would suggest only eating 50-75% of them back.

FYI: Not eating enough when you only have 20 lbs to lose will lead to a loss of a large amount of lean muscle, and less fat, than if you lost the weight slowly. Try setting your goal at 1 lb/week and eat 75% of your calories burned back.

Remember you burn over 2000 cals/day just living (no exercise) so if you burn another 2000, you would be burning over 4000 calories that day and if your goal is 1 lb/week you only need a 500 cal deficit which means on days you burn 4000 ish you should be eating 3500ish to lose your goal amount of weight.

it's very simple math. just addition and subtraction. there isn't even any long division involved.

it's very simple math. just addition and subtraction. there isn't even any long division involved.

What you should eat (Maintenance calories - your desired caloric deficit + exercise calories)

OP: if your maintenance is 2000 and your goal is to lose 1 lb/week and you burn 1000 from exercise/day you should eat 2500 (2000-500+1000)

General consensus shows that you should be eating your exercise calories.

OR don't eat them and find out what happens to how your body performs as the days wear on.

I question the math of your exercise burn. I've noticed a lot of people "overstating" their exercise calories burned (usually because of what's already in the database) and yet they complain that they are not seeing results.

Intensity of workout is key to calorie burn. If you are working out at a lower intensity than the database assumes, you aren't really burning those calories.

Do you have a Heart Rate Monitor to give you a more specific reading?

I think everyone has given you a good idea that yes - you need to consume a minimum NET calories of 1500 (more if you are close to your goal so as to decrease your daily deficit)... but a couple other have mentioned your exercise burn and HRM's - please make sure you are being accurate in these... 90 min of stationary bike is VERY unlikely to burn 1500+ calories. I realize MFP is setting that for you, but "vigorous" would mean extreme effort for 90 min which is nearly impossible IMHO for someone that still has 20+ lbs to lose.

Anyway, you've gotten good advice here - definitely eat more (lean proteins + veggies if possible!) and be wary of your "burn" measurements

I realize MFP is setting that for you, but "vigorous" would mean extreme effort for 90 min

For one thing if you are doing vigorous biking there is not way that it is vigorous, if you can do it for a full 90 minutes. Try to find a sprinter that can sprint for that long, vigorous means all out, which cannot be sustained over a 90 minute period, I would be lucky to do more than 12 minutes of vigorous anything, and I am quite fit.

The big thing with successful weight loss is CONSISTENCY is key. If you ate that little today I can bet my bottom dollar you might manage tomorrow, or even the day after but somewhere in the next 7 days you will lose it and lose it altogether.

I find it hard the idea of factoring in the exercise calories, for a lot of people they don't even log exercise but then make sure they are eating their calorie goal. That way you still have a defiicit but should have good results and not go into starvation mode.
I don't know what guys minimum eat is, for me its 1200 calories after that I get a note that says I'll go into starvation mode. The great thing is if I eat exactly 1200 calories it actually shoes me the weight I will be in 5 weeks which is lighter than if I ate less calories. It does work.
But I hear you, you have alot of eating to do I sometimes struggle making up the 1200 as I'm not used to eating that much. But eating more than normal is definitely working for me.

On the stationary bike I am tracking the speed as to not drop below 20mph and my heart rate ranges from 177 to the mid 180's. I am indeed pushing myself to the fullest because I have the desire to lose the weight. I am counting on it being off by a little not alot. I am not just relying on my given output but of course I am using certain supplements(i guess the site doesn't like you to promote so I won't name) one to burn fat and one for improving endurance.) So the numbers are either up or down but one thing is for sure I am going hard. Please don't question my effort or dedication to what I am doing.

The food is where my problem is. Food and retirememnt got me into the situation. I know I am eating to little was not sure what would be a safe amount. This thing only gave me the option to lose 2lbs a week. So I figured if that was at 1700(my initial goal) my thought was if I dropped that drastically I would lose more.

You may lose more, if you go below, but a lot of it would be muscle, not fat. A safe weight loss if you have 20-40ish lbs to go is 1 lb/week, if you have 40-75ish 1.5, if you have 75+ 2 lb/week. There is no reason to lose more than 2 lb/week as it is probably not healthy to do so. And the faster you lose, the more likely you are to put it back on.