Are calorie counts on cardio machines accurate?
You just spent 30 minutes on the elliptical getting your sweat on and the digital readout says that you burned 350 calories. Could that be correct? Pretty satisfying, right?!?
Hold up! The unfortunate truth is that most machines overestimate calorie burn by at least 15 percent, with the elliptical being the worst of the worst and overestimating calorie burn by up to 40 percent! That means you may have only burned about half of what the readout says!
Why is this? A host of factors influences calorie burn. Your sex, age, weight, height, lean mass, and fitness level all play critical roles in the number of calories you burn during a workout. The average cardio machine only accounts for your age and weight, and that's only if you put your data in before starting the workout.
To bring this point home, let’s imagine the following five scenarios:
Scenario 1: A man and a woman of the same age, height, and weight exercise for 30 minutes on the same elliptical. Do they burn the same number of calories? No! The man will burn more calories because most men have more muscle mass than a woman.
Scenario 2: Two women of the same age, height, and weight, exercise for 30 minutes on the same bike, but one is 35% body fat and the other is 25% body fat. Will they burn the same number of calories? No! The woman with the lower body fat (25%) has more muscle on her body, so she will burn more calories!
Scenario 3: Two men, both the same age, height, weight, and body fat percent, work out at the same pace on the same treadmill for 30 minutes, but one has been working out for 8 weeks while the other has just started a workout routine. Will they burn the same number of calories? No! The man who has been training for 8 weeks will burn FEWER calories than the man who just began exercising! The body “learns” to become more efficient, especially doing low-intensity cardio exercise like steady state walking, jogging, or biking. The more trained you are, the more efficient your body becomes and will burn fewer calories doing the same exercise!
Scenario 4: Two women, both the same age, height, weight, and body fat percent work out at the same pace on the same stair stepper for 60 minutes, but one of them was leaning on the rails the entire time. Will they burn the same number of calories? No! The woman who did not support her body weight by leaning on the rails will have burned more calories!
Scenario 5: A 120 pound woman gets on a treadmill and uses the “manual” setting which doesn’t require her to input age or weight. The manual setting on the average treadmill is set for a 155 pound man. Did she burn the amount of calories that the machine says? No! A 155 pound man will burn many more calories than a petite woman!
As you can plainly see, calorie burn from one person to the next is extremely variable, so relying on a machine can skew your view!
If you’re looking for the most accurate calorie count, use machines that allow you to put in as much data as possible including height, weight, age, sex, and even body fat percentage. Personal heart rate monitors are also fairly accurate at estimating calorie burn because not only can you input all of the above information, but adding heart rate to the equation gives a much better estimate of how hard your body is actually working during exercise.
The bigger problem with all of this is that people often use “calories burned" through exercise to justify eating more food. If Debbie’s elliptical tells her that she burned 600 calories, and Debbie decides to treat herself to a 190-calorie latte and a 200-calorie donut, but she only actually burned about 350 calories…you can do the math...this is not going to work out in her favor.
So what’s the point?!? Why even exercise?!?
When I track and count food calories (which I only do very occasionally), I never subtract my exercise calories from my food calories because it either leads me to overeat or over-exercise to compensate for overeating. I pretend I didn't exercise at all...that way I'm not tempted to overcompensate at the dinner table!
Unless you are an athlete engaged in intense training for a race or competition, my opinion is that people need to stop associating calories burned through exercise with the amount of food they are "allowed" to eat. It leads to the counterproductive habit of exercising to eat, and it’s plain to see from the above example with Debbie and the donut, that it’s very easy to overestimate calories burned through exercise and underestimate calories consumed through eating.
Additionally, the value of exercise is so much more than just burning calories! Don't work out for the sole purpose of being able to eat more! I mean, really, is a 500-calorie slice of pizza really worth running for SIXTY minutes on a treadmill? You'd be much better off with an intelligent meal plan that makes room for your favorite treats rather than trying to burn them off through exercise! So don’t get into that habit!
(Side note and shameless plug: if you’re looking for a program that can help you incorporate your favorite treats into your nutrition plan without having to kill your body with massive amounts of exercise, I have a 10 week online course starting soon! Check that out here.)