Are we really that inactive?

Posted on May 1, 2011

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In my post about why portion control shouldn’t be your first concern when attempting to lose weight, but eating less often should, I mentioned I was going to delve into some other topics talked about in the paper Why have Americans become more obese?

The next topic of that paper I wanted to look at is our activity levels.

Invariably people will say the reason they are overweight or can’t lose weight is because they are so sedentary. If they only didn’t have to sit at a computer 8 hours a day.

Bill Gates, Steve Jobs, you have ruined us all!

It’s a fair point. When it comes down to it we all know to lose weight you eat less. Or you move more. Or both.

Compared to when we were cavemen running around all day hunting for food we are obviously a lot more sedentary. And yes, compared to farming all day, helping out in a steel factory, facebook stalking is less strenuous.

But our being overweight / obesity has really taken off in the last 40 years. Are we really that inactive now compared to then (40 years ago)?

According to the paper, in 1910 68 percent of people worked an active job. By 1970, only 49 percent did. Between this time period humans as a whole became heavier. So it appears to be true: As we continue to get more and more sedentary we get heavier and heavier.

There is a big issue with this though. That issue is apparent after 1970. While we have gotten a little more sedentary, we have become A LOT heavier. In other words, the degree to which we have become less active does not match the degree to which we have gotten heavier.

For example, in 1990 it was reported the amount of people who worked an active job decreased to 42 percent (from 49 in 1970), yet the percentage of people who were obese in 1990 was nearly double that of 1970!

So 7 percent of the population started to move less yet 16 percent more of the population became obese.

Looking further into the data gives more clues why this is. Here is a chart from the paper showing how we have allocated our time over the years:

Let’s compared 1975 to 1995. We can see we don’t spend as much time doing things such as work around the house but we spend MORE time when it comes to recreational activities such as walking/hiking, sports, etc. In other words, yes, we have become less active during the day in certain areas of our lives. Yet we have offset that by becoming more active in other areas.

Now the authors never give concrete calorie numbers. Despite the fact I was a math major for a couple of years, I’m not sure I am interpreting their data 100% correctly. As far as I can gather though this change in our activity level comes out to where a 155 lb. male in 1995 would burn about 4 calories per day less than he would in 1975. (Even if it’s not exactly 4 the authors go out of their way to point out the difference is very small.)

4 calories per day less…

Again, yes, we have become less active, but it’s not proportional to our weight gain. Nor is it significant enough (4 calories per day!) to warrant a decent argument as to why we’ve continued to get heavier.

Furthermore, interestingly enough if you look at 1985 relative to 1975, we actually became more active through those ten years. This is apparently due to the fact we slept less and played more. The authors don’t really talk about this, or why it occurred, but I chalk it up to the advent of Bon Jovi.

I bring this up because, as expected, we got heavier from 1975 to 1985. As not expected though, this is despite us being more active. This further helps illustrate how our activity levels over the past 35 years have not made much of an impact on how much we weigh.

I am NOT saying people wouldn’t be a hell of lot better off if they exercised more and got more active in their everyday lives. Exercise has been associated with benefits in about a bagillion various areas. And up until you do crazy amounts of it, the more you exercise, the greater the benefits.

What I am saying is on average it does not appear the reason we keep gaining weight as a society is because we move less than we used to. There is a good chance you can blame the fact you eat more often than you used to and probably too much overall.

As I mentioned in the post on portion control, use this information to your advantage. Because you now know that just because you’re an accountant, computer programmer, or some job where you are sedentary much of the day, you can’t use that as justification for why you have weight to lose. Plenty of people 35 years ago were just as sedentary –or just as active- yet weighed less.

In other news, why do we eat more than we used to and how do we avoid it? Another post for another day.

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Posted in: Losing weight