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 was 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 don’t workout. 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.