Garmin - should I eat back all or half calories?

gorple76

My garmin (which uses HR to calculate calories burned) is synced with MFP. I wasn’t eating back exercise calories but now I’m planning to. Should I follow the ‘only eat half back because MFP overestimates’ advice or can I be more trusting of the garmin calories which infirm my MFP numbers? I understand I should evaluate and adjust as needed but just looking for a starting point.

Lietchi

I was very trusting of my Garmin and ate back every calorie from the start. It actually slightly underestimates my calorie burn even, I lose weight slowly if I eat at maintenance advising to my Garmin.

Depending on where the calories are coming from, you could evaluate?
I check my running calories with the calculator on exrx.net, and Garmin always underestimates for me. For rowing, I checked with the Concept 2 website and the numbers are a bit low too. (watch out, the calories burned per exercice session are gross calories, so don't compare with net calorie calculators)

gorple76

Thanks @Lietchi. I’ll check some of my numbers against a calculator and go from there. I’m a bit confused about the net vs gross aspect though. It looks like the gross calories are added to MFP. Should I be deducting my bmr from that figure each time to make sure I’m only eating back net calories?

Lietchi

The gross versus net calories is only an issue when comparing with other calculators to check calorie burns for exercice.
It's not an issue for your calorie adjustment on MFP. MFP compares total calorie burn for the day, so the BMR calories included in the exercise calorie burns, are taken away in the calorie adjustment.
To give an example: when I'm on holiday, I might do a multi-hour hike, but be quite sedentary the rest of the day. Garmin will give me 1000 calories for my hike, but on MFP the Garmin calorie adjustment will show several hundred calories negative adjustment (because of the BMR calories from my hike being 'taken away'). The total adjustment will still be positive though and no calories are being double counted.

Lietchi

This is what it looks like on hiking days:



It's an extreme example (the longer an exercise session, the higher the number of BMR calories) to illustrate that there is no double counting.

gorple76

Thanks again @Lietchi. Somehow I’d had the negative adjustment disabled (presumably I did it when setting up not understanding what it meant). It all makes a lot more sense now 😂

NorthCascades

Turn on (allow) negative adjustments.

My Garmin overestimates cycling by HR, seems pretty reasonable for walking. Pick whatever seems closest to you and follow it for a month or two and two predicted weight vs reality. Which it sounds like you're planning to do anyway. I'm not sure what type of exercise you plan to do and I don't know what situations it's better and worse at predicting calories for for the most part.

coryhart4389

I have been using Garmin and MFP for about 2 months. IMO, the Garmin overestimates calories burned or I’m underestimating calories consumed. I do use an oz. scale for food, but something is off by about 500 calories per day. I would start with half, like you suggested.

AnnPT77

NorthCascades wrote: »

Turn on (allow) negative adjustments.

My Garmin overestimates cycling by HR, seems pretty reasonable for walking. Pick whatever seems closest to you and follow it for a month or two and two predicted weight vs reality. Which it sounds like you're planning to do anyway. I'm not sure what type of exercise you plan to do and I don't know what situations it's better and worse at predicting calories for for the most part.

This.

When it comes to fitness trackers' giving a good estimate, I'm reasonably convinced it's not so much how accurate the device is, it's more about how average any given user is. Fundamentally, these devices give statistical estimates - quite personalized ones - based on averages from large populations. Most people are close to average, by definition. A few aren't, for reasons that may not be obvious.

I love my Garmin, but don't synch it to MFP, because it's so far off for me on all-day calories (it's 25-30% low, compared to 6+ years of logging and weight tracking experience) . . . even though others here have reported that the same model is quite accurate for them. One can just log the tracker's exercise calories (not all-day calories) in MFP, but in theory it would be better to subtract estimated BMR calories for the time period, and log the net, if not synching the device. In practice, for normal-length exercise sessions (half hour to hour kind of thing), that's not arithmetically of huge importance IMO, but it can be for very long but low-burn activities like slow walking.

I log the whole exercise calories it estimates for my exercise (theoretically double-counting BMR/RMR and some NEAT for that time period). Since the device estimates low for me overall, I speculate it's possibly low for exercise too, so I just log the full calories from any exercise, eat them all back, and everything works fine, even with seasonal and other variations in exercise. Since I'm still at a healthy weight 5+ years post-loss, it seems to be close enough, in practical terms.

I don't understand why so many people seem to believe that if a device's exercise estimate is wrong, it must be too high, so everyone should eat half of it. It can be high, it can be low. In a context where slow loss is frustrating, and fast loss is a health risk (unless one is severely obese, at least), underestimating exercise can be a problem, too.

The fastest loss isn't necessarily the best loss. And, to handle maintenance well, it can pay off to experiment and figure out what's reasonably accurate practice for *you*.

gorple76

Thank you all for your advice. I’ve set up the sync correctly now and might try eating back all of the net calories logged for the next 4 weeks and see where I end up. I’m not good at restriction and seeing one number but then cutting that in half will be a bit of a challenge. If I can avoid that I will be happier. I mostly run and checking against calculators, garmin seems fairly reasonable in its estimates. I’m starting some resistance but those calories are low so less if a concern if they’re a little off i guess.

heybales

For running it's usually a good estimate, as it's using HR and distance-based calculations which are more accurate.

Also, your daily activity is based on the distance steps takes you - it's merely displaying HR at other times, not using it.

So indeed the Garmin info sent to MFP is right for MFP to do math with correctly, despite how Garmin shows it on their site with Active calories.
And for sure don't worry about Garmin attempting to use the MFP base eating goal and adding Active calories to it - their understanding of how it works is flawed with how they do things.
So forget Garmin's displayed eating goal.

Just meet the MFP new eating goal that includes everything, glad you got the Neg adjustment enabled, for sure needed.

Just to clarify - it's not really net calories logged.
The workouts are the gross calories. That's what the estimated total burn was for that chunk of time, to compare to almost everything else that also displays gross calories.
The adjustment is merely the difference between accounts for daily burned, given and pre-estimated.

You can tweak Garmin for physical stats if desired to keep using it synced if your food logging is felt to be accurate enough and you think the issue is on the burn rate calculated. Taller increases BMR and default stride length (so greater distance to your daily steps) so increases calories burned, messing with weight can do some of the same too.

gorple76

Thanks @heybales thats super informative. As a side note, I’ve not been able to weigh myself the past few weeks and finally stepped on the scale this morning. I’ve lost 6lbs in 4 weeks which was a pleasant surprise (I’d had a bit of a stall the two weeks before). It looks like whatever I’m doing is working for me so feeling much more reassured and trusting of the process.