Another weight myth bites the dust in today’s daily research fix. (Of COURSE you were jonesing for another study. There, there, now. Settle down. I’m a gonna take good care of you.) Right after “I’m big boned” the most common excuse for being overweight is “I just have a slow metabolism.” But is it true? What does the research say?
We can all cite a Jack Sprat & His Wife example (side note: why does she not have a name?? I vote for Sybill, I love a good alliteration) from real life. Doesn’t everyone have a friend like my old yoga buddy Kelly who can eat cheeseburgers and candy bars all day every day and not gain an ounce? [insert appropriate skinny-fat warning here] And we probably all know people who subsist on a meager 800 calories a day and yet still battle their weight. But does the research support the idea that obese people have slower metabolisms than lean people?
The Study
Nope. Sorry. According to this study from the Pennington Biomedical Research Center, obese women and lean women have almost the same resting metabolic rate (less than a 100 calorie difference). Your RMR is how many calories you burn just exisiting every day. Any activity on top of that, like exercise or work, requires additional energy and therefore more calories.
The study also examined the women’s activity levels and discovered that the obese women sat 2.5 hours more each day and spent half as much time in activity as lean women. This equaled out to about a 300 cal/day difference.
Caveats
Problem 1: This study was in no way comprehensive. The sample size was a whopping 20 women (10 in each group). Small sample sizes = less accurate results and less generalizabilty to the greater population.
Problem 2: It’s a chicken and egg thing – were the obese women less active because they were obese? Or were they obese because they were less active? Actually, I suppose it’s more of a vicious cycle with the obesity and the lack of activity feeding into each other. So forget the chickens and eggs. If you still need a mental picture go with cows. They’re much cuter. But still irrelevant. And now you’re hungry. You’re welcome.
Conclusions
Stuff you already pretty much knew: move more, eat less. Rocket science, people! But drop the old adage of a slow metabolism because, barring a health condition like hypothyroidism, chances are it isn’t your metabolism that’s slowing you down.
Photo Credit: Gallery One
I have heard the same thing before that obese people have the same metabolism and I found that very interesting.
I unfortunately am the type that has to subsist on the lower end of calories but I also know that I am not a saint at the eating right all the time.
I loved jack sprat and sybill is a great name!
Candice
I have really found the concept that we create our metabolisms, rather than being born with a set metabolism, to be very fascinating and motivational. It is one of the big reasons why I don’t diet because dieting pretty much wrecks metabolism. Instead I try to focus on consistency and slow but permanent changes.
It can be sooo easy to succumb to the many excuses that others give us as for why we are the way we are (I have to constantly remind myself NOT to use having 5 kids as a weight excuse). In truth it is the way we live our lives that make us who we are (and that goes WAY beyond just food and exercise).
I think you are assuming that what people mean by “metabolism” equals calories expended. Maybe it is the ability to extract calories from food.
I was once told by a doctor that I could eat only lettuce for a year, and I would still gain weight. His point was that I was basically storing every last gram of energy that entered my body. I was not obese, but wanted to lose 20 pounds and it was really hard.
And I have friends who eat absolutely everything, and are normal-to-thin, and some (many more) who don’t eat that much but eat more than I do, and are thin. And I could kick their butts in any fitness test, bc I exercise far more than they do.
Oh, well. I no longer feel bad about it.
Maria – Thanks for your comment! I totally get what you are saying. I had a roomie in college that could eat everything in sight and still not gain an ounce (how we didn’t stab her in her sleep, I’ll never know). What they study is saying, I believe, is that the difference in resting metabolic rate (how many calories are needed just for living) for the AVERAGE obese person and the AVERAGE lean person is small. The difference isn’t enough to make a significant difference in weight loss/gain, esp. compared to other factors like nutrition and exercise.
That said, there is a wide range of what in normal in human beings and I definitely agree with you that there are some people that gain weight very, very easily while others don’t. I think this research applies to the majority of people that fall around the statistical mean. And it sounds like you are an “outlier”.
You have a great, positive attitude – I love that you exercise like a fiend! Because exercise is about so MUCH MORE than weight loss. And health cannot be meaured by weight. Post more often – I’d love to hear more from you:)