The problem with studying exercise for weight loss is that you can’t really disguise the exercise.
If exercise came in a pill you could do it.
You could get a big group of people and randomly give half the pill with exercise in it, and the other half a dummy, sugar pill that looks, smells, tastes etc just the same (aka a ‘placebo’.)
This is the scientific way to test whether pills works for weight loss.
But what about exercise?
It’s a bit hard to have a ‘dummy, sugar pill’ for physical activity. The sweating and heart-pumping bit sort of gives it away.
What this means is that for exercise for weight loss there is no way to do the gold-standard of a “double-blind, placebo-controlled” study.
Is this a problem?
Oh my wordy, YES!
Time after time it has been shown that the psychological power of medicines is a huge part of their overall effectiveness.
But is this specifically a problem for exercise and weight loss?
Well I only know of one good study that covers that question.
The researchers didn’t invent a dummy, sugar pill, but they did the next best thing as Ben Goldacre at Bad Science reports…
Alia Crum and Ellen Langer from Harvard psychology department took 84 female hotel attendants in 7 hotels. They were cleaning an average of 15 rooms a day, each requiring half an hour of walking, bending, pushing, lifting, and carrying.
These women were clearly getting a lot of good exercise, but they didn’t believe it: 66.6% of them reported not exercising regularly, and 36.8% said they didn’t get any exercise at all.
The study abstract reports that one group of the hotel attendants was…
…told that the work they do (cleaning hotel rooms) is good exercise and satisfies the Surgeon General’s recommendations for an active lifestyle. Examples of how their work was exercise were provided.
Subjects in the control group were not given this information.
Although actual behavior did not change, 4 weeks after the intervention, the informed group perceived themselves to be getting significantly more exercise than before.
As a result, compared with the control group, they [the hotel attendants who were told that their cleaning job was in fact ‘exercise’] showed a decrease in weight, blood pressure, body fat, waist-to-hip ratio, and body mass index.
These results support the hypothesis that exercise affects health in part or in whole via the placebo effect.
Now here is the really interesting bit.
HOW MUCH weight did people lose in 4 weeks merely by being thinking they were exercising?
These details are from PsyBlog…
The average weight of those in the intervention group reduced from 145.5 lbs to 143.72 lbs. Over the same period the control group showed no significant change. For those of you working metric-style that’s 66.14 kg down to 65.33 kg.
That’s weight loss of almost 2 pounds, just under 1 kilogram, in just 4 weeks.
Not bad huh, for doing nothing extra?
So here’s the kicker.
Doesn’t that sound scarily similar to the 1 kilogram or 2.5 pounds in 12+ weeks that is the ENTIRE benefit of exercise anyway?!!!
[If you didn’t know this was all exercise does, see my previous post with the scientific evidence.]
Exercise, if done for weight loss alone, has suddenly become not just a minor factor, but instead an utter waste of time!
Could this really be the final nail in the exercise / weight loss coffin?
Massive industries of gyms, fitness equipment manufacturers, personal trainers etc etc hope it’s not true.
But what is there left that could resurrect exercise as a real weight loss tool?
If any one knows, I’m all ears.
-Dr Martin Russell