This story on NPR reports on a recent study whose authors claim that it shows that the placebo effect can be effective in weight loss and fitness. (You can find the citation and abstract on PubMed here.) Ellen Langer, a psychologist at Harvard Medical School, worked with a sample of hotel maids--whose work is nothing if not physical--to reframe their thinking about their level of exercise. Though these women are on their feet and moving around all day, often hauling heavy carts and vacuums, they didn't consider themselves to be getting much exercise. More to the point, their physical health status didn't reflect the amount of exercise they were getting on the job.
The researchers divided the women into two groups. Women in the experimental group received information about exercise and encouragement/education intended to help them understand that they are already meeting national guidelines for daily activity. Women in the control group received no information. On follow-up, the women who had received the education showed weight loss, lower blood pressures, etc.
The researchers conclude that these changes can be attributed to the educational intervention--that is, that by understanding that they were getting enough exercise for it to improve their health, their health was improved.
Critics comment that because the study was based on self-report and not observation, there's no way of knowing whether the women in the experimental group made other changes--eg, improved their eating habits--perhaps as a result of having their awareness raised through the intervention. Without these missing data, it's impossible to make direct claims for the efficacy of the educational intervention, because other factors could account for the differences that were observed afterward.
This study raises interesting questions about the placebo effect and just how much our thoughts control our physical status. It also brings up some caveats and lessons for all of us who get our medical information from the media. News stories, after all, focus on the interesting finding--not on the validity of the methods employed to reach those findings. As more and more information becomes available to the public through relatively unmediated forums (ha! like this blog!), we all need to take a more critical stance.