Thoughts on fitbits?

I have a charge 3 and find it to be pretty accurate for my calories burned based on my weight loss. Overall I am happy with it. I can get 5-6 days before it needs charging again. I've found it to be motivating. Sometimes I'll take that extra lap around the block to see those green circles close. And I like seeing the sleep info. I do wish I had looked at Garmins more for some of the running features.

There is no medical correlation between wearables and longterm weight-loss. That being said, I have a fitbit Alta. I like the heartrate monitoring and the fact that it buzzes 10 minutes before the hour if you have less than 250 steps that hour as a gentle reminder to stay active. It is fairly accurate, though I don’t think it counts steps very well when pushing a grocery cart. Sometimes it counts false steps if I’m clapping or doing an activity where my hands/arm are active.

I have a Garmin Vivoactive 3, which I like and I find useful.

IMO, at least three kinds of people are going to find a "fitness tracker" device helpful:

1. People who do some fitness activity for which the device will provide training data that helps guide the training process. This might be pace/speed data, distance, heart rate ranges, etc.
2. People who are motivated by having numerical goals, and/or a social-media context that allows competing with others for those goals. For example, I've had groups of friends who all got the same device, then compared and competed on step counts and that sort of thing. It helped them be more active.
3. Data geeks, people who just like having and tracking various kinds of numerical data for fun.

I'm a #1 and #3 person, myself.

Any of these devices - at least the good quality ones - just give you a calorie figure that's estimated based on research and statistics. It's the same general approach MFP uses to give you a calorie estimate, but more personalized. The device doesn't in any way measure calorie burn. It measures things that tend to have a correlation with calorie burn. Depending on the specific device, those measurements could include heart rate, GPS speed/distance, changes in elevation, arm movements, and that sort of thing. It then combines those measurements with your personal data (weight, stride length, age, etc.) to estimate calorie burn.

If other statistical estimates of calorie goals/burns tend to be pretty close for you, these devices are likely to be pretty close for you, too. I'd go further, and say that the good devices are likely to be pretty close for most people, because that's the nature of sound statistical estimates. But they'll be further off for a few people, and quite far off for very, very few (the people who are quite different from the average person in some unknown way).

The Garmin model I have produces pretty good calorie estimates for quite a few people, based on what I've read on MFP. But it gives pretty inaccurate calorie estimates for me (just like MFP itself does), for complicated and partly unknowable reasons.

I like it anyway, because mostly I care about #1 and #3 on my list above. If I wanted to, I could calculate how far off from reality it is, on average (because I have 4 years of calorie/weight logging data), and use a percentage adjustment to get a decent-ish daily calorie burn estimate (because I am a data geek, after all). But I already know how I need to eat to maintain (or lose) weight, so I haven't bothered. I love the pace/distance data for monitoring my on-water rowing progress, though.

I use a Fitbit. I have used several different models over the years. I have also used Garmin, Polar and Apple Watch.

I find any of them to be “accurate” in the sense that they are consistent. If I have roughly the same kind of a day, doing the same kinds of things, they will produce roughly the same stats as all the other times I’ve had days like that day. The step counts, calories burned and whatever else are consistent-but not necessarily “accurate”.

However, for me, consistency matters the most. If I have consistently weighed & logged food, compared my actual weight change to what is predicted, I can determine what kind of adjustment I need to make to whatever numbers the device is tracker is spitting out. I’ve had some that seemed to be pretty dead on, some that read quite high (consistently) and some that read quite low (consistently).

I use trackers to encourage me to move (I work a desk job at home), friendly competitions, and because using the device (with the above consistency being established) takes the stress out of wondering how active I am-or how many calories to add to the 2 days a week I waitress-or what if I worked a double-or I did a lot of moving or gardening or whatever....

So...I would never assume that any of the numbers given to me by a tracker are lab-accurate. Step counts will be off. Sleep numbers will be kind of wild. Calorie counts could be high/low/normal. But they will be consistent. And I can work with that.