What’s my deficit?

BlueberryRipple

I hope someone can help! I have been trying to find out what my actual calorie deficit is on the system – i.e. if I finish the day on around “0 cals remaining”, what deficit have I achieved (this assuming any exercise from my linked Fitbit has been added by MFP and eaten by me).

Can someone point me to where I can see this on the app?

Many thanks in advance.

Lietchi

You won't find it anywhere. But you can deduce it from your weight loss rate settings.

Losing 1lb per week = deficit of 500 kcal per day, multiply or divide as needed according to your selected weight loss rate.
For the metric people, losing 0.5kg per week = deficit of 550 kcal per day,...

BlueberryRipple

Thanks for your help - I appreciate it.

On Friday:

On Fitbit, I ingested 1632 cals (logged from MFP) and I burned 1863 cals (Fitbit HRM device).

On MFP I had a calorie goal of 1200 set and I was awarded 437 in exercise, of which I ate 1632.

I’m on a 2lbs a week goal. From the above, I’ve only achieved a deficit of 200. MFP has awarded me too many extra calories?

Am I completely misunderstanding it all?

AnnPT77

Did MFP give you the 1200 calorie goal based on what you put in your profile settings? It won't give a woman a goal lower than 1200. Reason: Eating too few calories increases health risk, simplistically stated.

Maybe you know all about this stuff, but I'm going to type it anyway, just in case. Hope that's OK.

Be aware that both Fitbit and MFP are giving you estimates that you will need to be test and verify as accurate for you. They're not giving you assured-true facts.

If those estimates are true, and you burned 1863 calories according to a Fitbit that you wore continuously for the whole day, you are correct, about a 200 calorie deficit.

How fast did you tell MFP you wanted to lose weight? A pound a week is a 500 calorie deficit. Eating 1363 on that day would be expected to give you a pound a week loss, averaged over several weeks. If you asked for 2 pounds a week loss, that would require a 1000 calorie deficit. You'd need to eat 863 calories to achieve that. IMO, that would be a truly bad idea.

For some of us, even a 500 calorie deficit may be excessive. It depends on current body weight, among other more complicated variables like health history, overall life stress, etc.

Earlier, I mentioned testing and verifying the estimates. How long have you been at this? Results averaged over 4-6 weeks (whole menstrual cycles if you have them) will give you your best possible estimate of your actual deficit.

My good brand/model fitness tracker, which I wear 24x7 except when charging briefly, says I've averaged 1611 calories burned daily over the past year. For that same year, without doing the detail arithmetic to give you a precise number, I've been eating/logging more like 2100-2200ish calories. Even on non-exercise days, my base goal is 1850, and I eat that. On January 12, 2024, I weighed 135.0 pounds. Today, I weighed 133.6. That doesn't exactly suggest that my tracker's estimate is accurate for me, does it?

Like I said, maybe you know all of this. But just your raw numbers make me wonder whether you're wanting to lose kind of aggressively fast for your current size and nutritional requirements. Not my call, of course.

totameafox

find a tdee (total daily energy expenditure) calculator so you know what you burn from what you do. then subtract the calories you consumed

BlueberryRipple

Ann, thank you so much for your careful explanation – that does make sense and thank you very much for it.

You’re right, I had set up a 2lbs loss rate and the system has allocated me 1200 cal daily.

However, I’m very short – under 5 feet – and pretty old too – over 60. So I get that it’s difficult to get to 1000 cal deficit without doing a huge amount of exercise – which I don’t do!

So I guess I’m surprised that it awarded me 437 additional calories. I appreciate that it’s unrealistic to expect a deficit of 1000 cal, but it could have awarded me less or none, so that I was closer to that deficit? Had it not awarded me those calories, I would’ve had a deficit of > 600, rather than 200.

I’m thinking of using MFP solely to track calories using their superior database, and then using the Fitbit app interface to import those calories and manage the deficit, as it seems to be able to do so a lot more accurately.

Thanks again for the time you took to help me, I really appreciate it.

AnnPT77

BlueberryRipple wrote: »

Ann, thank you so much for your careful explanation – that does make sense and thank you very much for it.

You’re right, I had set up a 2lbs loss rate and the system has allocated me 1200 cal daily.

However, I’m very short – under 5 feet – and pretty old too – over 60. So I get that it’s difficult to get to 1000 cal deficit without doing a huge amount of exercise – which I don’t do!

So I guess I’m surprised that it awarded me 437 additional calories. I appreciate that it’s unrealistic to expect a deficit of 1000 cal, but it could have awarded me less or none, so that I was closer to that deficit? Had it not awarded me those calories, I would’ve had a deficit of > 600, rather than 200.

I’m thinking of using MFP solely to track calories using their superior database, and then using the Fitbit app interface to import those calories and manage the deficit, as it seems to be able to do so a lot more accurately.

Thanks again for the time you took to help me, I really appreciate it.

It doesn't necessarily surprise me, but that doesn't mean I think it's being exactly right, either. Figuring out how to do this if truly petite, older, less active may therefore require some thought.

Loosely and in theory, what the MFP fitness tracker sync does is compare what MFP expects you to burn all day, with what the tracker saw you burn all day, and increase calorie burn if the tracker saw you as burning more than MFP expected. I'm not sure how MFP defines "what's expected" in a case where they've reined in your requested loss rate because it would put you under minimum 1200 calories.

In practice, you have options here. You could manually set your goal lower than 1200 . . . I think. (I haven't tried it, because I wouldn't set my goal that low, even at 5'5", 133 pounds, and age 69, because I know from experience I personally need many more calories than that even for basic energy level!) Even if it won't let you set lower than 1200, you have the option of eating less than 1200.

I'm not sure I'd suggest that, though, because of health risk. One potential option would be for you to estimate your protein and fats needs in grams, see how many calories that adds to, add a reasonable number of carbs, then use that result to estimate your calorie needs. That might cut the nutritional risk down somewhat.

Another - probably better - option would be to un-sync your tracker, and log exercise manually, although that's mildly less convenient. That would be in a context where you've estimated your pre-exercise TDEE (total daily energy expenditure), so you know your estimated current weight-maintenance calories. You could then log exercise calories manually, but only log enough calories to keep your current estimated deficit.

Does that make sense?

Now, probably someone's going to come along and suggest you should only manually log the net calories from the tracker, and that the tracker's probably telling you gross calories. You don't need to read it, because I think this is unlikely to be a big deal in real life, but I'll put the explanation and semi-solution in a spoiler below to throw some water on those possible flames. (And will explain why I say it's probably not a big deal.)

* Net exercise calories: Most trackers display total calories during the exercise time slot. What we ideally want to add to MFP is just the ADDED calories burned by the exercise, not including the calories we would've burned in that time slot just sitting around. Depending on the exercise, the difference may not be big enough to matter.

Here's how I'd estimate how many calories to subtract from the total calories for myself, if I wanted to estimate the net: My Garmin estimates I burn 1354 "resting" calories daily. For a rough estimate of net exercise calories, I'd divide that by 24 to get a rough per-hour resting estimate, so about 56 calories per hour. That's still not perfect, because I likely burn fewer resting-ish calories asleep than the number of calories I burn sitting in my chair awake typing this, but close enough for this purpose, IMO. There are ways to get closer, but really, really not likely to be worth the effort.

Let's say I do 35 minutes of exercise, and my tracker tells me the total calories are say 266. To get net calories, I'd divide to get the fraction of an hour, 35 divided by (so 35/60), which is about 0.58. I'd then multiply the result by hourly resting calories of 56, to get rough-estimated resting calories for 35 minutes: About 33 calories. To get net calories for the exercise, subtract 33 from 266 to get 233.

Is that arithmetic fuss worth it for 33 calories? IMO, in the big picture, probably not All this stuff is estimates, and 33 calories isn't going to make or break my weight management effort. YMMV.

It might make a difference in some truly long but very gentle exercise, like 2-3 hours of casual walking. But for intentional exercise walks, I'd use this calculator to estimate instead, and just pick "net" in the energy box:

https://exrx.net/Calculators/WalkRunMETs

Also close enough, IMO. Relatively few other intentional exercises will be long enough and gentle enough to worry about that, at least among things I personally do.

Generally, I think the easiest adjustment probably would be to have a rough estimate of your daily calorie needs, let the tracker sync, and just not eat all of the exercise calories if that would put you over maintenance calories for TDEE including exercise. If you like, you could create a custom food in MFP to capture those calories, and log yourself as having eaten X calories of that food to subtract some part of the exercise calories.

Whatever's easy for you, and helps you accomplish your goals. That's what I'd do.

P.S. If you want to estimate your TDEE with or without exercise, this is the calculator I like for that sort of thing:

https://www.sailrabbit.com/bmr/

It has a crazy busy-looking user interface, but it lets you compare several research-based estimating formulas, makes all the calculations explicit, and has more activity levels with better descriptions than most other TDEE calculators. There are other TDEE calculators in the world, if that one doesn't appeal to you.