Why “Calories Burned” is a Terrible Way To Judge Your Workout

There isn’t a person who goes to a group fitness gym who hasn’t at some point graded the effectiveness of their workout via the amount of calories it burned, whether it be from a treadmill, a watch, a heart rate monitor, or witchcraft sorcery like “Splat Points”.

We get it. Totally.

The reality is that many folks, hell, the majority of us still use this measurement as the singular determinant of a workout’s “effectiveness.” That is a major mistake on many levels and it makes our heart sad and lonely.

Now, for those of us who like to wear and track our workouts, there are of course some excellent merits. First, it can be a fine way to baseline your efforts and gather biofeedback about what the appropriate effort level is for your workout. Second, when you wear something health focused, you tend to do more health focused things. Third, many of us like to have the workout data as part of an overall picture of how active we were that day. Steps, standing hours, etc. So the clear point we want to preface is not to trash the ideology of why you use fitness wearables.

What we do want to scream loudly from the mountaintop is the false logic in using ‘calories burned‘ to dictate the overall efficacy of your fitness program, and brainwash your decision making by only attending high “calorie burning” programs or workouts. After all, throw a dart at a fitness brand and chances are it boasts the amount of calories it will burn you in a workout as the reason to go there.

That is a hot trash approach that we want you to stop for the following reasons.

1. Burning Calories Doesn’t Always = Progress

The technology behind wrist heart rate monitors is pretty simple. Essentially, they are tracking your heart rate and making some assumptions about your height and weight to calculate what it thinks is a reasonable assumption for your energy expenditure, aka, your caloric burn.

Your heart rate monitor has absolutely zero idea what movement you are performing, what muscle group you are working, and what weight you have selected to lift. Does that sound like a technology that can paint a complete picture of whether or not a workout was good? All of those things are significantly more critical to your results than how close you can get your heart to explode in a workout. The reason is because your body and fitness only really improve when two things happen:

  1. You get stronger.
  2. You build muscle.

Strength training develops lean, athletic muscle and improves your overall endocrine profile, which leads to an improvement in fat burning efficiency. And building muscle will directly impact your physique, performance, life span, and ability to burn calories.

Both are lower heart rate intensive efforts than high cardio workouts, thus, would falsely appear to be not as effective to those who are calorie burning junkies.

Your heart rate is always going to be highest when you’re in a state of high aerobic output, like running. Doesn’t necessarily mean you made any actual physical progress.

2. Your Watch Hates Strength Training

What does strength training not do?

Elevate your heart rate to the same degree as cardio. Why? Because it is shorter work sets, more recovery, and greater efficiency. You don’t have to turn yourself in a hamster to get results, therefore your heart rate monitor is going to spit out a low “caloric burn” component of the training, despite it being the unquestioned best way to get results.

Your Basal Metabolic Rate (BMR) is the amount of calories your body burns at rest, daily. Metabolically, building muscle is very advantageous because the amount of muscle you have on your body is directly proportionate to how many calories you will burn during your day. This is scientific fact.

Meaning, a 155 pound woman comprised of 23% body fat will burn far more calories than a 155 pound woman with 30% body fat.

So, the woman who has more muscle on her body at the exact same weight will not only be leaner, but will maintain her leanness due to her improved metabolic activity. This is why it’s very “easy” to maintain your results in strength training once you get them.

Consider this from a 2012 NCBI study:

“Because evidence suggests that resistance training may promote a negative energy balance and may change body fat distribution, it is possible that an increase in muscle mass after resistance training may be a key mediator leading to a better metabolic control.”

If all you do is play slave to your calorie burning, you will NEVER allow yourself these scientifically proven benefits of strength training and building muscle. Both objectively do not burn as many calories as a cardio effort, yet both are vastly supreme in their ability to get you results.

3. Your Watch is a Dirty Little Liar

Do you think that in some crazy scheme to turn a profit, these manufacturers made their devices overestimate the amount of calories you burn so that you’re happy with the outcome and want to keep using them?

No way.

Stanford University studied the Apple Watch, Fitbit Surge, and five other popular brands of fitness watches back in 2017 and discovered that not a single one of them had below 20% rate of error when it came to measuring calories burned in its users. Not one.

While technology has improved since then, no doubt, they are still highly questionable when it comes to functional fitness. Consider this from the Cleveland Clinic: “Using your arms for exercise activities — like with an elliptical that has hand levers to work your arms — can cause inaccurate readings.”

Oh. Well. Good thing exercise doesn’t use your arms then.

Who knows if the intent behind the error is nefarious or if it’s a technology that’s still just developing, but does it matter? It’s not entirely correct.

4. Psychologically Damaging

This obsession with calories burned can also have a very damaging carryover effect to your food consumption, which can carryover to your pyschology. If the amount of calories you are burning is being misrepresented, it may lead you to make poor food choices because you think you burned a certain amount in your workout and in fact did not, or worse yet, that you didn’t burn enough to “earn” a particular meal.

This is a sneaky reason why a lot of calorie chasers don’t change their physiques much at all. Disordered eating around food that leads to an overstressed endocrine system and underfed metabolism.

Tread carefully here in that supposed 600 calorie workout you’re doing. And that one thousand calorie workout your boot camp gym says you did? Hate to tell you this, but total bullshit. Science does not substantiate that kind of output for the human body in forty five minutes, and even if a workout allows you to maintain that kind of pace, it’s a terrible workout physiologically that would utterly destroy your body long term.

What To Do Instead

If you are a calorie addict who needs a place to rehabilitate yourself, start with this: go heavier, and slow down a gear. The best plan is one that respects all aspects of a fitness program without overdosing any one of them. Continue to use your calorie tracking as you see fit, but instead make it one variable of how you judge your progress, not the be all end all of your workout self worth.

Focus on strength training 2-3 times per week, and performing shorter, more intense conditioning workouts 1-2 times per week that are always using resistance training in some form.