We can totally relate.
Almost everyone who has access to a smart watch or fitness tracker has at some point assessed the quality of a workout by the number of calories burned.
You’ve pushed yourself to finish a difficult workout and that number is just staring you in the face.
And you’re first thought is…that’s it?
Despite my best efforts, on a very regular basis I’ll hear someone comment with a disappointing tone about the number of calories they just burned.
Fitness wearables on the whole are positive. These devices provide valuable biofeedback and insights into our activity.
People wearing fitness tracking devices tend to focus on increasing their healthy activities. I’m a huge advocate for heart-rate training and my intention with this post isn’t to discourage the use of fitness-tracking devices.
I do however want to raise public awareness that Calories Burned is the worst metric you could track with your workouts.
Now that I’ve made my claim, here are the top 5 reasons why you should stop paying attention to the number of calories burned in your workout.
Fitness Trackers Don’t Accurately Measure Energy Expenditure
In 2017, Stanford University studied the seven most popular fitness devices.
While six out of the seven measured heart rate within 5% accuracy, none of the devices accurately measured energy expenditure (calories burned). The most accurate device was off by 27% and the least accurate was off by 93%.
These devices are based on a formula that doesn’t take into account your individual metabolic rate, the muscles you’re working or the weight you’re using.
In early 2024, we had someone wear two fitness trackers while working out on equipment that also calculated calories burned. The reported calories burned on the fitness trackers differed by more than 300 and the fitness equipment reported a number significantly lower than both wearables.
Burning More Calories Doesn’t Mean Better
A well-rounded fitness program will include both strength training and conditioning that incorporates both high and low intensities.
Focusing exclusively on maximum calorie burning would be the nutritional equivalent of only eating foods with higher amounts of Vitamin C. There are other vitamins, micronutrients and macronutrients needed for optimal nutrition.
Imagine driving your car in such a way that you maximized the RPMs of your engine. You wouldn’t expect the engine to last and you shouldn’t drive your body that way either.
Strength Training Matters Too
Focusing on calories burned usually leads to focusing on conditioning (commonly referred to as cardio).
For reasons mentioned earlier, fitness trackers don’t capture the entire picture when it comes to strength training.
Adding lean muscle to your frame with strength training will improve your metabolic rate which allows you to burn more calories on a daily basis.
While conditioning workouts tend to burn more calories in a given workout, this comparison doesn’t tell the entire story.
Conditioning workouts won’t help you increase your lean muscle tissue or the number of calories you burn when you aren’t training. This is one of the reasons strength training should be included in your fitness routine.
Improved Efficiency Results In Less Calories Burned
When you regularly perform a given exercise, you tend to improve your efficiency with that exercise. As your movement quality improves, your body requires less energy to perform the same amount of work.
If calories burned is the ultimate metric, you’re looking at continually increasing the amount of exercise you do just to burn the same number of calories.
Someone who has been exercising for less than one month will burn significantly more calories performing walking lunges (or any other exercise) than the person who has been exercising for 5 years.
The goal is to get better so you can improve your efficiency and movement quality.
The Constrained Model of Total Energy Expenditure
In his book Burn, Herman Pontzer describes his findings from research on the Hadza, a tribe of hunter gatherers. His research has blown the lid off everything the fitness industry THOUGHT it knew about burning calories.
It turns out that we burn calories in a very narrow range…regardless of our physical activity.
Hunter-gatherer tribes were only burning a few hundred calories per day more than a sedentary desk jockey.
When we burn additional calories with our training, the body takes away energy from other areas such as reproduction, digestion, recovery, etc.
You can’t burn a never-ending amount of calories in a day because it requires both time AND energy to turn your food into the ATP your body can use as fuel. This also explains why simply adding more exercise doesn’t equate to weight loss…even when caloric intake is controlled.
What To Focus On Instead of Calories Burned
As mentioned earlier, we are huge advocates of heart rate training, and we recommend using Morpheus.
These devices take several metrics into consideration in determining your daily recovery score which then impacts your heart rate zones for the day.
Morpheus also provides you with weekly targets for the 3 heart rate zones. This ensures you are building an aerobic base without compromising your recovery with too much higher intensity work.
Training at the right volume and intensity for you as an individual produces the best results with the Minimum Effective Dose.
