Monday, November 02, 2009
Image by Dan Taylor.
I came across a very cool study last week which was published in the latest issue of the American Journal of Preventive Medicine. In this new paper, Dr Gabrielle Turner-McGrievy and colleagues at the University of North Carolina at Chapel Hill examined the impact of listening to a weight-loss podcast on body weight, physical activity, and fruit and vegetable consumption in overweight men and women. Subjects were randomly allocated to one of two groups; the control group which received a popular and freely available podcast focused on avoiding over-eating, and the experimental group, which received an "enhanced" podcast created by the study authors. This enhanced podcast was based on Social Cognitive Theory, and included specific information on what to expect when attempting to lose weight, specific goals to achieve, and knowledge about how to achieve these goals. Both groups received 2 podcasts each week for 12 weeks, and only met face-to-face with the researchers at the baseline and post-testing sessions.
So, what happened? In comparison to the control group, the group which received the "enhanced" podcast experienced significant increases in their knowledge of weight loss topics, fruit and vegetable consumption, and their level of vigorous physical activity. Finally, the enhanced group also experienced a 2.9 kg (~6.5 lb) reduction in body weight.
Now I find this study very interesting for several reasons. First and foremost, it was done in the real world. This was not a study where the authors strictly controlled the diet and physical activity levels of their participants. In fact, they purposely minimized contact with their participants! This is the opposite of many studies, which strictly control the lifestyle of their participants, effectively sequestering them from the day-to-day life. So while the weight loss and positive lifestyle changes in the experimental group were modest, there is good reason to think that they could persist over the long-term, since they have presumably been incorporated into normal daily life. And if any type of lifestyle change is to be maintained over the long-term, this is what has to occur. I also find the idea of podcasting interventions extremely appealing because they are cheap and easy to make as well as to download, making them incredibly accessible. And finally, in contrast to interventions which provide information in print, people don't need to sit down to listen to a podcast! I listen to podcasts all the time during my ride to work, during workouts, and when walking to school, and it really is an easy way to take-in information.
Now keep in mind, this study was only 12 weeks long, and the participants in the experimental group only lost about 6.5 lbs. Also, diet and physical activity measures were obtained through self-questionnaire, rather than being objectively measured, which introduces quite a bit of error. And finally, the control podcast - which the authors report is a very popular weight-loss podcast - had absolutely no impact on body weight or any other variable of interest. So to answer my own question in the title of this post, podcasts are probably not the cure for obesity. But evidence-based podcasts like the "enhanced" podcast in the present study may provide a useful tool for people looking to make a positive lifestyle change, and that's definitely a good thing.
A big hat tip to my girlfriend Daun for sending me the link to this study.
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Turner-McGrievy, G., Campbell, M., Tate, D., Truesdale, K., Bowling, J., & Crosby, L. (2009). Pounds Off Digitally StudyA Randomized Podcasting Weight-Loss Intervention American Journal of Preventive Medicine, 37 (4), 263-269 DOI: 10.1016/j.amepre.2009.06.010
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