MFP estimates your daily non-exercise burn purely from age, gender, weight, height (to get BMR) and your selection of Activity level outside exercise (as multiplier to BMR, honestly selected or not).

So Fitbit is reporting what it saw as daily burn to MFP. That obviously includes exercise since it's just daily burn.

MFP makes an adjustment either way to make it's estimate match with Fitbit's better estimate.

If you receive a negative adjustment, it means you burned less according to Fitbit than MFP thought you would.

Now, if you logged exercise on MFP and it didn't sync over to Fitbit to replace it's calorie burn for that time, then MFP is comparing daily non-exercise maintenance plus logged exercise to Fitbit.

If Fitbit didn't get the sync of a more accurate and higher calorie burn for exercise, then it'll be reading way low what it reports to MFP.
Negative adjustment.

The other way you get this - you burned more in exercise - but were lazier for rest of the day.
So while you burned 700 more than non-exercise maintenance, by the end of the day you actually lost 259 calories.
Meaning your exercise didn't actually have you burn more today - likely because it made you tired enough you did less. Or you exercised when you normally would have been active anyway, so while 700 during the workout, you would have burned 300 anyway.
Now add in moving less during the day - negative adjustment.

I don't think it's possible for a guy to be given a 1200 daily goal - they used to stop at 1500. Did you make it a 1200 goal?
That's the bottom of barrel limit for reasons of safety for a sedentary woman - so I sure hope you eat more than 1200.

Your eating goal with I'm guessing a 2 lb weight loss goal would have been 1840 then.

In your MFP Profile settings - what do you have your non-exercise activity level set to? Lightly Active, Sedentary?

You might also confirm on that MFP page that shows the adjustment, by clicking on the 'i' for more info - what MFP received from Fitbit regarding total burn. If it doesn't match, then a sync did not happen.

I do not use either app, and my syncing is within seconds. If you look at mine for Saturday, my exercise logged on Fitbit was 1704 calories, but I was also more active in general so adjustment was even higher.

The other way you get this - you burned more in exercise - but were lazier for rest of the day.
So while you burned 700 more than non-exercise maintenance, by the end of the day you actually lost 259 calories.
Meaning your exercise didn't actually have you burn more today - likely because it made you tired enough you did less. Or you exercised when you normally would have been active anyway, so while 700 during the workout, you would have burned 300 anyway.

This sums it up perfectly:drinker:

I try to think of it this way - keep in mind: I don't know if this is the "correct" way to look at it, but it helps me understand it better in my own mind. This (IMO) is the simplest explanation I can think of. BTW, I have a FitBit Flex linked to MFP.

If my FitBit calorie adjustment is shown as a positive number, I view that as having met or bypassed my MFP projected goal for normal daily activity ONLY! If my FitBit calorie adjustment is shown as a negative number, I view that as NOT having met my MFP projected goal for normal daily activity, making me aware that I need to get up and move more.

For example, I just relinked my FitBit to MFP yesterday afternoon, because I got lazy for a couple months due to having surgery in December. I logged a workout through FitBit last night, as I walked a little over two miles. But because I did not have my FitBit on all day, my calorie adjustment showed up as -104, and I was told that I basically overate 65 calories, even though I only ate 1451 calories out of 1490. So I wouldn't expect to lose any weight based on these readings. But today, I've had my FitBit on since this morning, and my calorie adjustment has already registered as +93, plus I'm shown that I can still eat 499 calories safely for the day. I'm assuming this reading will change if I walk more steps throughout the day, which I plan on doing. Again, please realize that this is ONLY for my normal daily activity levels...this would not include calorie burn for any strenuous exercise or workouts that I may do later. I log all walking/ jogging/ hiking exercises through FitBit (for obvious reasons), and any other exercises (such as elliptical or weight training) I log directly though MFP. I take my FitBit off during these types of exercises, just to be certain that I don't get double readings on anything.

I don't know if this is the correct way to figure any of this, but it SEEMS to make sense. If anyone can see that I might be incorrect in how I am looking at this, please feel free to contact me or reply to this post, because I'm always looking to make sure that I'm doing things correctly, and welcome any guidance throughout my process.

By the way, my original weight loss prior to having surgery was 118 lbs. I've gained back 35 because I had a nasty tonsillectomy and ended up with quite an infection, and I caved with the ice cream during recuperation. I'm back on the road to healthy eating and exercise now, and I'm hoping I'm reading into the FitBit calorie adjustment correctly!

2 things - first, click on the negative adjustment and check the time of the last sync from Fitbit to MFP - many times, it breaks and it may have not updated all day, so it hasn't gotten the updated calorie adjustment after you input your workouts.

If it has recently updated, then the second thing to check is what you have your activity level set for on MFP. If MFP still thinks you should've burned more 259 calories more, even with your 700 calories of exercise, then you need to lower your activity level on MFP. For example, you may have it set to highly active, and it needs to be lowered one level. That should lower your daily calorie goal and get it closer to Fitbit. When you adjust this, you can see what calorie goal MFP is going to give you and this number should very closely match the number Fitbit gives you.

If Fitbit said you burned 2840 that day including the 700 of exercise, then that means without exercise your expected calorie burn is 2140 (on Fitbit side).
If you have your calorie goal on MFP set to 1200, that's a HUGE deficit. You more than likely have MFP set to lose 2 lbs per week and it won't let you go lower than 1200.