New devices measure your metabolism, but how accurate are they?
To maintain your weight, you need to match your calorie intake to your calorie usage. And if you're trying to lose weight, you need to make sure that you consistently take in fewer calories than you are using.
Most people simply estimate how many calories they can afford using tools such as our Daily Needs Calculator. But there are a bunch of new gadgets on the market that claim to give you an exact read on how many calories you're burning.
Just how accurate are they? Perhaps less precise than you might think The type of devices that are worn next to the skin--costing anywhere from $50 to $200--can be off by anywhere from 10% to 30%. If you're willing to fork out significantly more ($7000 to $10,000), you can buy a device that measures your resting metabolism when you breathe into a mask for several minutes. These calorimeters can reveal individual differences in basic metabolic rate but can't tell you how many calories you are burning through exercise and other activities.
Here are links to reviews of some of the latest gadgets:
Find out how many calories your body burns (Chicago Tribune)
How accurate are devices that track calories? (Wall Street Journal)
Or, you can keep doing it the low-tech, low-cost way. Use a standard formula such as the Daily Needs Calculator to put you in the right ball-park. Pay attention to how many calories you are actually eating. (Our tracking tools can help.) Adjust as necessary. If you're maintaining your weight, you've found your calorie balance. To lose weight, cut back on your intake or step up your output.
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Posted by: kristianna | Sep 28, 2009 11:02:40 PM
Hi...
I have read this article.It is great to know.My boyfriend and I were having this discussion tonight -- he is a cyclist and is training to race, and wanted to test his metabolism. I will forward your article to him! Thanks!
cd
Posted by: Dave Orrino | Jun 30, 2009 12:00:44 PM
I'm more of a fanatic than your average bear. I track every gram and ml of food and drink I take in. I use a program called Calorie King. I also use one of those body fat scales. I hear they are not that accurate but that the error is at least constant. I also use a heart rate monitor to estimate calories burned during exercise. I have an Excel spreadsheet set up that takes my total calories consumed for say a month, then adjusts for calories burned through exercise and weight gained or lost. This really worked for me because the total calories I consistently calculate is 400 - 500 calories less than the Daily Needs calculator here or other places like the American Heart Association. Yes, I know this sounds like overkill but I keep the data anyway so I just used it. Also, I have noticed that my calculations don't change that much whether I track my calories and exercise for a week or a month so if somebody wanted to do this you don't have to commit to a long period of time to get a good feel for your base metabolic rate. I used 3500 calories for each pound of fat gained or lost in my calculation.
Posted by: fat preacher | Jun 29, 2009 10:17:39 PM
"To lose weight, cut back on your intake or step up your output."
Or,better yet, do both!
Posted by: Bart | Jun 29, 2009 4:51:46 PM
Also, your body adapts to changes in diet and exercise level, so the number of calories you burn daily is never static. Accordingly, we have to be work with inexact estimates.
