Think yourself thinner

Within four weeks of learning that the physical demands of their daily tasks provided good exercise, the 44 room attendants lost an average of 2 pounds, lowered blood pressure by almost 10 per cent and logged statistically meaningful reductions in Body Mass Index, body-fat percentage and waist-to-hip ratio, compared with the 40 housekeepers in the uninformed group.

Members of the informed group also perceived themselves as getting significantly more exercise than before, even though their workload and recreational exercise levels, as well as diet, remained constant.

Not everyone is buying the results.

8220;My first thought was, 8216;When are they publishing it, April 1?8217; 8221; says Patrick O8217;Neil, director of the Weight Management Center at the Medical University of South Carolina. 8220;And I8217;m a clinical psychologist,8221; he adds. 8220;These are my people.8221;

Lead author Alia Crum, now a predoctoral student at Yale University, acknowledges the provocative nature of the study, which is one of very few to test a placebo effect in exercise. 8220;It8217;s funny,8221; she says of the report, published in this month8217;s issue of Psychological Science. 8220;Initially everyone was trying to discount it, saying, 8216;Well, they just exercised more,8217; because we have pretty firm notions of how to lose weight, and this is counter to those ideas.8221; But the results are not all that incongruent with studies on the placebo effect. 8220;We get stuck in the notion that you8217;ll lose a pound for every 3,500 calories 8212; that weight loss is just a matter of what goes in and what goes out 8212; and we forget about all the other components that might be involved, like our mind-sets,8221; she says.

O8217;Neil believes the findings can be chalked up to something much simpler. 8220;These results are more readily explained by the fact that the people in the informed group received more information related to health and exercise,8221; which led to undetected changes in activity level, he says.

Dr Harvey Simon, associate professor of medicine at Harvard Medical School and author of The No Sweat Exercise Plan, believes in the power of the mind and the strength of the placebo effect, but suggests that in this case the most likely culprit is a change in the women8217;s diet.

8220;It8217;s not a hard trick to lose 2 pounds in a month with a change in diet,8221; he says, pointing out that the study did not closely track what the women were eating.

Simon was more impressed by the drop in blood pressure. 8220;If people are mentally feeling better and healthier, there could well be a psychological effect.8221;

Crum acknowledges that there8217;s no way to know for certain whether the attendants, after hearing of the health benefits of the tasks they were doing, might have been unconsciously doing things a little differently, such as putting more 8220;oomph8221; into their work.

But co-author Ellen Langer, a psychology professor and Crum8217;s faculty adviser at Harvard, bristles at the notion that the results could be accounted for by changes in behavior that simply flew under the methodological radar. Research suggests that 8220;we have more control over our health and well-being than we realise,8221; she says, 8220;and the bottom line is that the way to achieve this is by increasing our mindfulness8221; to the tasks at hand.