A common reason people don’t do as well as they think they should be doing when following a calorie counting weight loss program is that they simplify the First Law of Thermodynamics (Calories In vs. Calories Out) far too much.
(Trust me – I’m an expert on Thermodynamics, having taken it three times at Duke. Got it right the third time, though – and that’s all that really matters, right?)
What most people do is accept the calorie reading on food labels. Really, what constitutes a “medium-sized” apple? What about Washington apples versus Maine. Or Fuji versus Macintosh? You get the point.
Then they look at the number on their treadmill or elliptical, pull out their calculator, and can’t understand why they’re not losing a mathematically predictable amount of weight per week.
Sorry, figuring out the science of calories in/calories out is not that simple (as I’m sure you’ve noticed in your mirror). (For starters, you’d have to burn your feces to figure out how many calories you’re flushing down the drain. No, thanks.)
A big part of the problem is that your exercise machine is dead wrong!
A research study at the Human Performance Center of the University of California at San Francisco tested the calorie readings on exercise machines (specifically the treadmill, stationary bike, stair climber, elliptical machine and special heart rate monitors) and compared them to what’s called VO2 testing.
(The V is for “volume” and the “O2″ is for oxygen as I’m sure you remember from high school chemistry. Sorry, chem geeks, but this blog won’t let me use a fancy subscript for the “2″ in O2.)
Although using VO2 test data to calculate caloric output introduces a degree of error – it entails taking human variables such as height, weight and body composition into account – it’s the still most accurate, affordable way to measure calories out during exercise.
Here’s how the machines stacked up compared to VO2 testing:
- Elliptical – overestimated calories burned by 42 percent
- Treadmill – overestimated by 13 percent
- Stair Climber – overestimated calories 12 percent
- Stationary Bike – overestimated by 7 percent
The watches overestimated by 28 percent.
To give you an idea of how far off your elliptical machine might be:
When it says: 150 cals
You’ve burned closer to: 106 cals
When it says: 250 cals
You’ve burned closer to: 172 cals. That’s a 78 calorie difference. About the same as that medium apple :-)
Hmm. (As someone who used to write an exercise machine review column for a national magazine) It’s curious that they all overestimated calories burned. Wouldn’t YOU love – and want to buy – a machine that magicallyburned more calories than other things you’ve tried?)
The best way to use the calorie counter function on a machine is to use it as a guideline only.
Instead of thinking, “I burned 127 calories on the elliptical machine today,” think “I did 127 UNITS [you can even make up your own name here] on the elliptical machine today. That’s 11 more UNITS than the other day, so I’m making progress.”