Is your fitbit set to synch throughout the day or do you only synch a few times via PC?
Initially before I got an android phone I was only able to synch when I woke up and before I went to bed, but wasn't using neg adjustments either (this was prior to that feature)

Also do you have neg adjustments enabled?
Are you activity levels set the same on both?
It's a bit of a learning curve when using both but honestly I just use it as another tool and try not to eat based on fitbit vs mfp .. i find a middle ground if possible..

If you exercise regularly maybe considered doing tdee so that you can eat the same amount every day regardless of exercise.

This is an 'issue' that MFP has no solution for in my opinion but you can figure it out.

The problem is that we have no way of telling MFP "hey, I'm done for the day" and it assumes we're going to keep burning calories as if we're active. I've not figured out any way to adjust for this. Which means MFP always thinks we're going to burn more for the day as a result.

HERE is my solution. I backwards engineer my calorie range.

Set a goal in Fitbit for how many calories you plan to burn each day. Lets say its 2250. You know your BMR estimate, at with 1338 it means your hourly is about 55 calories per hour. So if you want to burn 2250 total then at 11pm you'd need to be at 2195, at 10pm 2140, and so on. Deduct 55 for each hour left in the day. Meaning if you're at 2140 at 10pm, you know you'll hit 2250 when your BMR kicks in and time passes. If you're aiming for 500/day then eat in the 1600-1750 range. If you've eaten 1700 and your burn is 2140 at 10pm, MFP will tell you that you have 100-200 remaining because it thinks you're going to keep going. But you know better.

Then just do what it takes to hit that burn level. If you're at 2000 and its 9pm, you're not done for the day.

Then plan your calorie intake range based on your burn goal. When you are done for the day, MFP just doesn't have an off button.

My goal is to burn 2000, and most days I eat 1600-1800 for a 250 deficit. (Plus a little to spare, most days.)

My actual Fitbit burn and MFp's estimate (including my Fitbit Adjustment) end up just 2 calories different when all 24 hours are factored in.

I think the issue is that Fitbit only credits you for your burn after it has happened (assuming the device is synched so any movement is factored in). MFP needs a 24 hour estimate for its process. So it guesses based on your activity level (in your MFP settings). While the day is in progress, MFP's guess is based on your actual Fitbit burn for time passed and your MFP activity level for time remaining. Even set to the sedentary level it assumes some activity (something like 1.25 times your BMR). If you sleep or are completely inactive, Fitbit only credits you with your BMR (which is correct for sleep and probably close enough for other inactivity). So every hour sleeping or inactive can mean losing some of the Fitbit adjustment MFP credited earlier. The earlier credit was usually wrong since you were not as active as MFP wrongly projected. How to work with this? I found it can help if you look at your previous MFP diary after you have synched your Fitbit in the morning. See where your adjustment ended, was it more or less than when you checked the night before. If you do this a few times, you might notice a pattern in how many calories you are losing. I try to leave about 100 calories uneaten (I don't always succeed), if I do that a few times a week, it usually covers what I lost in my adjustment. Actually I don't worry about it too much anymore, but I did do that in the past and it worked out well for me.

I don't worry about Net--I have only seen this on MFP (I've used several other diet sites and plans). I only worry about total deficit, I think this "net" as MFP defines it does overcomplicate this a little. Sorry MFP! I agree that I should eat a certain minimum in order to get good nutrition. I never set my goal deficit higher than 500 calories and I almost always eat more than my BMR (usually 200-400 calories more), but my minimum goal is actually around my BMR (slightly less, my BMR is 1200andsomething, MFP sets my minimum as 1200). The net on mfp is in relation to whatever activity level you are set for so it is actually kind of arbitrary.

The one thing that I find that helps with stalls and plateaus is tightening up on food logging. The big thing is weighing portions and logging them by weight--so far I haven't had a plateau that hasn't helped with (because for me I reach plateaus when I stop food logging or when I am eyeballing portion sizes). If really stuck, I assume I am underestimating food intake and will manually add on 10% of the calories I logged. I had read that food labels can have an error of 20% legally and had read an article (I think in New York Times online) that they had tested food from several restaurants in NYC and almost all the food had more calories than listed in the nutrition data (to be fair, it is hard if not impossible for a small business to get that exact). So I kind of figure any food I ate that I didn't make from scratch likely has more calories than I logged (though this is true for food I make too since I don't have the expensive equipment used to analyse this). Using a food scale is easy for home foods, if it were not, I suppose I would just add 20% onto my guesstimated portions for a week and see how that works. I rebel against using a food scale for some reason, but it is actually cleaner, more accurate and easier than using measuring cups and spoons.

Saving to read later. Good info!

I have my Fitbit food plan set to "personalized" rather than sedentary. On the personalized setting the starting allowance is based on your average calorie burn (over the past few days) minus your deficit.

Where in the Fitbit food plan process can you select "personalized" vs. sedentary?

Sorry for such a basic question, but I just got my fitbit today.. how exactly do you 'sync' your fitbit and why do you do it?
Thanks:)

Top menu ......look for APPS next to Community. Choose your device.

You Sync it to MFP (not everyone does) because you want it to show you the difference between the activity level set in MFP vs. your actual activity level for that day. If you have lots of ups & downs.....or you are trying to maintain...this is a good thing.

Let's say I choose sedentary in MFP.....but walked 10 miles that day. How do I account for 10 miles? I can't log all 10 miles because part of that is included in sedentary.

The part that confuses users (takes getting used to) is that the FitBit clock starts at midnight. You have burned calories before you logged into MFP that morning (your BMR). So, don't let the morning, mid-day, adjustments throw you. What matters is the end of the day.