Why Calorie Trackers Don't Work



It's kind of amazing to me that we're getting to the stage now where people think that they need one of these fandangled heart rate monitors or activity trackers.

I mean, people were getting in shape just fine before they became available, just a few years ago.

(not knocking this guy, just the general state of affairs)

Fitness wearables are not without their uses of course; they can help people with motivation and provide valuable data on performance.

But when it comes to tracking the amount of calories you burn, they are pretty much useless.

Precision Nutrition (who I trust and recommend) estimate that the margin of error is up to 25%.

This is based on the margin of error for the tracker itself, the fact that individuals burn calories at different rates, plus what you eat and your weight history influencing how many calories you burn.


Given all that, a 25% margin of error might not sound too bad, but it's enough to completely sabotage your efforts to lose weight.

Say you need to consume 2000 calories to lose weight. But you eat 2300. So you do 30 minutes on the treadmill, which your tracker says burned 350 calories. Sweet, you're back down at 1950 for the day. Except, the margin of error is 25%, so you might only have burned 260 calories... Which means you're actually at 2040 calories for the day.

And if that's happening every day then you're not going to lose weight as quickly as you should... Or worse, you might even end up gaining weight.

So to answer the original question:

Figure out roughly how many calories you should be consuming to reach your goal. This isn't an exact science, either, so you'll need to stick with that number for a few weeks, and then step onto a scale to check if you've gained or lost weight. Depending on your goal, you can adjust from there.


Future reading