Being fat is just like carrying a heavy backpack, right?

I mean, everyone assumes it is, so it must be, right?  Nobody needs to research this because we know what they’d find, right?

Studies that simulate obesity in nonobese people suggest that putting on pounds substantially increases the metabolic cost of walking. When lean women walk with heavy, bulky gear strapped to their legs and bodies, [locomotion researcher Rodger] Kram says, “their energy costs skyrocket.”

But in recent experiments, Kram and his University of Colorado colleague Raymond C. Browning found that obese women1 somehow avoid paying most of the expected penalty. The heavy women seem to have learned to carry their bodies efficiently. […]

In the May Obesity Research, the researchers report that, compared with the other volunteers, the obese ones spent only 11 percent more calories per kilogram when moving at optimal speed over a given distance. Given the difference in size between the groups, the metabolic cost could have been more than 100 percent greater for the obese women, the researchers say.    […]

“That suggests [the obese volunteers] are changing their gait to conserve energy,” Browning says.

(From Science News, emphasis mine.)

Really?  Why, that’s as if the fat human body were still one human body that adapts to change over time, instead of a thin human body with extra padding!  That can’t be!  Why, next someone is going to claim that doing the same exercise repeatedly would increase efficiency! 

Note the original article assumes that this energy-efficiency is automatically bad because it reduces the number of calories a fat person burns while out for a walk, and thus thwarts the expectation that “exercise causes weight loss in all fatties (so if she’s fat she don’t exercise)”.  There’s not even a hint that fatties can exercise regularly, improve their health, and yet not lose weight, because, of course, if you don’t lose weight it’s completely irrelevant.

Well, the article does note that this energy-efficiency might be related to fat people putting less stress on their knees…..

[Researchers Paul] DeVita and Timor Hortobágyi found that a person who weighs twice as much as another experiences no greater torque in the knees when both walk at the same, reasonable speed. When the obese volunteers were allowed to walk at a slower speed, which they found more comfortable, they exerted even less force on their knees than people in the other group did at the faster pace. Greater force on the knee had previously been presumed to explain why obese people are susceptible to osteoarthritis in that joint.

Furthermore, DeVita and Hortobágyi reported in 2003, obese volunteers walked with shorter strides and straighter knees than did other people. Those behaviors reduce certain stresses on the joint, DeVita says.2

So:

  • When a fat person’s body adapts to use less energy to walk than a thin person in a fat suit3, it’s bad.
  • When the fat person’s body adapts to put less stress on their knees to walk than a thin person, it’s … a reason to be careful in changing a fat person’s gait to be less efficient.

In neither case is this seen as fat bodies taking care of themselves or doing something GOOD.  In neither case is this seen as evidence that being fat is at all natural for some people. No, these are problems to be solved. God forbid that fatties might be glad that their body can adapt to put less stress on their joints!

~ * ~ * ~

1Average BMI of 34 (abstract here) so probably “plus” sizes not extended sizes/supersize. Remember, I’m a BMI of 60; most obese people weigh significantly less than me!
2The abstract is here.
3Yes, I realize that fat suits weren’t used in this specific research. But there is a similarity between thin women walking “with heavy, bulky gear strapped to their legs and bodies” and a thin woman wearing a fat suit. Fat suits are commonly used in “fat like me” stories, complete with “OMG I was so tired walking around with all that weight, no wonder fat people never exercise!” observations.

3 thoughts on “Being fat is just like carrying a heavy backpack, right?

  1. Amen. The blind prejudice & the total resistance to seeing that fat is a normal, natural, genetic variation in body size & not a ‘problem’ to be solved & that it is not possible to explain differences in body size either by eating or exercise habits is mind-boggling. I have arthritis, & yes, it affects my knees, even one big toe, but my worst pain most of the time & my greatest limitation is in my hands…&, no, I don’t walk on my hands. I have walked, in 59 years, at least 50 thousand miles, over & above the walking we do just living & moving about our homes, stores, offices, etc., & have done other exercise as well, & I am still fat. Barring a serious, debilitating, long-term illness, I likely always will be.

  2. Oh yeah, I remember that article. It was released a few years ago and I thought I had blogged about it but I can’t find the post. I really hated a lot of the language. You quoted a lot of it but there was also this:

    obese people might force themselves to walk in ways that take more energy, which would help them lose weight but might also elevate their risk of developing osteoarthritis in their knees.

    Because surely everyone would rather be thin with bad knees than fat with good knees.

    By understanding how obese people conserve energy and by encouraging them to alter their walking motion to neutralize energy-saving adaptations, the researchers say they might be able to promote weight loss.

    Never mind using this understanding to improve joint health or efficiency (in everyone). Promoting weight loss is all that matters.

    “We may be able to get around their energy-conserving mechanism by making them walk uphill,” Browning says.

    Positively Sisyphean.

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