Home Exercise 101Fat Loss Study Analyzes Calorie Management vs. Exercise For Weight Loss

Study Analyzes Calorie Management vs. Exercise For Weight Loss

by Erika Nicole Kendall

I was quite pleased to see this in the NYTimes (and shoutout to Somerset for sending it in!), what with all the talk about food and calories I do all day:

And in a just world, frequent physical activity should make us slim. But repeated studies have shown that many people who begin an exercise program lose little or no weight. Some gain.

To better understand why, anthropologists leading one of the new studies began with a research trip to Tanzania. There, they recruited volunteers from the Hadza tribe, whose members still live by hunting and gathering.

Providing these tribespeople with a crash course in modern field-study technology, the researchers fitted them with GPS units, to scrupulously measure how many miles each walked daily while searching for food. They also asked them to swallow so-called doubly labeled water, a liquid in which the normal hydrogen and oxygen molecules have been replaced with versions containing tracers. By studying these elements later in a person’s urine, researchers can precisely determine someone’s energy expenditure and metabolic rate.

The researchers gathered data for 11 days, then calculated the participants’ typical daily physical activity, energy expenditure and resting metabolic rates. They then compared those numbers with the same measures for an average male and female Westerner.

It’s long been believed that a hunter-gatherer lifestyle involves considerable physical activity and therefore burns many calories, far more than are incinerated by your average American office worker each day. And it was true, the scientists determined, that the Hadza people in general moved more than many Americans do, with the men walking about seven miles a day and the women about three.

But it was not true that they were burning far more calories. In fact, the scientists calculated, the Hadza’s average metabolic rate, or the number of calories that they were burning over the course of a day, was about the same as the average metabolic rate for Westerners.

The implication, the scientists concluded, is that “active, ‘traditional’ lifestyles may not protect against obesity if diets change to promote increased caloric consumption.” That is, even active people will pack on pounds if they eat like most of us in the West.

The underlying and rather disheartening message of that finding, of course, is that physical activity by itself is not going to make and keep you thin.

I’m curious about this part, here:

In fact, the scientists calculated, the Hadza’s average metabolic rate, or the number of calories that they were burning over the course of a day, was about the same as the average metabolic rate for Westerners.

…but… people with different body sizes burn different amounts of calories, so are we comparing the “slight” Hadza tribemembers (someoneplease tell me if that’s politically correct) with the “slight” Americans? If I were 5’9″ and 200lbs, and I run six miles in an hour, I’m going to burn way more calories than someone who is 5’9″ and 130lbs. The 130lb body doesn’t require as much energy to move the weight, because there’s not as much weight to move as there is in the 200lb body.

Dare I ask it, but are averages appropriate here?

And what about the body fat percentages of the Hadza tribemembers in comparison to the Americans?

And, what about the nutritional intake?

Do these variables still not matter in the minds of epidemiologists?

There is, however, one other part of the article that Ithought was very interesting:

“There’s this expectation that if you exercise, your metabolism won’t drop as you lose weight or will even speed up,” says Diana Thomas, a professor of mathematics at Montclair State University in New Jersey, who led the study.

But she says close mathematical scrutiny of past studies of exercise and weight loss shows that that happy prospect is, sad to say, unfounded. One of the few studies ever to have scrupulously monitored exercise, food intake and metabolic rates found that volunteers’ basal metabolic rates dropped as they lost weight, even though they exercised every day. As a result, although they were burning up to 500 calories during an exercise session, their total daily caloric burn was lower than it would have been had their metabolism remained unchanged, and they lost less weight than had been expected.

Now… I’ve said this twice – here, and here – but it bears repeating: your metabolism changes as you lose weight. Your ability to burn changes, as you lose. That’s why it’s so difficult to lose as you shrink in size.

What else did you spot in the coverage on this study? I know a few other places covered it and maybe they have different points they’ve highlighted… so let’s talk it out!

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Laurena August 2, 2012 - 12:01 PM

How does this match up with the news stories about how many thousands of calories Michael Phelps and other elite athletes need?

Erika Nicole Kendall August 2, 2012 - 1:46 PM

Ahhh, nice question.

This is also why I said I think body fat percentage also should make a difference, too. I’m pretty sure Phelps has like 4% body fat. ROFL

Kaycee August 2, 2012 - 12:30 PM

Good article and great analysis. I like your point about comparing apples to apples, I’m tempted to give them the benefit of the doubt that they made sure the groups were comparable in size. O) I just wish I could get this thyroid to work so some of this might apply to me and I’d be happy. I see my doc in 13 days and I’m so excited I don’t know what to do. lol

*trying to stay encouraged*

seynabou August 2, 2012 - 1:28 PM

Hi Erica,

first of all: keep up with the great work!!
My question about your post is: why are you calling these scientist “epidemiologists”?

Thanks 🙂

Erika Nicole Kendall August 2, 2012 - 1:43 PM

Do you object to the term, as if I might be denying them the right to be called scientists?

The World Health Organization defined epidemiology as, “Epidemiology is the study of the distribution and determinants of health-related states or events (including disease), and the application of this study to the control of diseases and other health problems. Various methods can be used to carry out epidemiological investigations: surveillance and descriptive studies can be used to study distribution; analytical studies are used to study determinants.”

I think a study like this is most valuable to epidemiologists, which is why im curious as to whether the variables are clear or if they even matter to them. It doesn’t disqualify them from being scientists, but epidemiologists focus specifically on obesity and obesity-linked illness, which is what this study is related to, IMO.

I mean, I’m more than willing to change the post if it’s setting off alarms I didn’t intend to set off.

Kaycee August 2, 2012 - 3:09 PM

I think seynabou is thinking that we usually refer to epidems as germ/bacteria/infectious disease docs. lol

Erika Nicole Kendall August 2, 2012 - 3:14 PM

Ahh, I see! Is it improper or confusing? I can change it if so.

marie August 2, 2012 - 3:53 PM

No don’t change it !
Then everyone who does not know this can learn a new word 🙂
I actually thought that it was disease related LOL… now I am clever 😉

NIKNICHOLE August 2, 2012 - 3:18 PM

This is a very interesting article and it really shows that calories burned versus calories eaten is the key. The important thing is to stay under the calories your body normally burns in a day at rest (BMR) if you are not working out.

Kaycee August 2, 2012 - 3:23 PM

I don’t think its that big a deal, you’re definition is correct. I think people are just used to seeing epiderms as the docs in Contagion, that’s all. :O)

Greg Kuhn August 2, 2012 - 4:56 PM

This is exactly why I exercise to feel good, rather than to lose weight. Quantum physics clearly shows us that we are holistic, rather than machine-like, and our bodies will never respond in predictable fashion to any exercise program. But if I’m interested in feeling good, I always win because I can almost always feel good (whether I’m “losing weight” or not).

Thanks for this awesome post, Erika!

kemi August 3, 2012 - 5:47 AM

i live in Nigeria and i don’t have a ready-made access to the calories in foods i consume e.g our local foods likewise an estimate of amount of calories i burn daily? what can i do?
presently i am 100.9kg @ 5ft7in…down from 106kg in 3mths….

Erika Nicole Kendall August 3, 2012 - 9:52 AM

Firstly, congrats!

Secondly, you can get a rough estimate of your daily caloric burn by using this formula here, after doing any necessary conversions from kg to lbs.

Lastly, if you stick to fruits and veggies, you can get a rough estimate of your caloric intake. If you have access to calorie counting apps like Lose It! or MyNetDiary (which I’ve grown to LOVE), then it gets much easier.

Best of luck to you, mama! 🙂

CurlsCoilsStef August 3, 2012 - 1:55 PM

Laurena you also have to take into account that Phelps is working out all day. Your daily calorie intake would be higher if you worked out 8-10 hours a day like Phelps. Think about it when your sitting down all day working (if you have a desk job) your not burning as many calories as a person who is running, swiming, and weightlifting all day. The reason Phelps can eat that way is because he is burining way many calories than what he is eating. Also don’t be fooled he is a world class athlete what he is eating for fuel not for fun.

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