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July 15, 2006

New thoughts on the causes of obesity

photo of obesity and food billboards, taken by ktheory, flickr.com

There's a very interesting article about obesity on slate.com. Sydney Spiesel, who's a professor of pediatrics at Yale and who's been looking at some recent scientific papers on the subject, explains why the simple "you eat too much and exercise too little" view may be missing some other significant factors:

Not enough sleep -- Inadequate sleep may change the levels of two hormones that induce feelings of hunger.

Heating and air conditioning -- Hot sleeping temperatures depress appetite, cold sleeping temperatures cause the body to burn more calories during sleep.

Chemical contamination -- There's growing evidence that a number of chemical pollutants in the environment mimic the behavior of female hormones, which can stimulate the body to accumulate fat.

But I thought the most interesting part of the article comes at the end, where Spiesel talks about a study by T.J. Wilken et al in Nature that examines attempts to get some obese schoolkids to lose weight. It turns out that increasing physical activity almost never helps these kids...they seem to have an amazing (and only semi-conscious or unconscious) ability to adjust their total amount of activity throughout the week. Make them go to gym class an hour a day, and they'll end up expending less energy the rest of the day.

This all may leave parents of an obese kid bit depressed, but then Spiesel talks about one thing that he has seen work in his patients...positive self image:

...adolescents who lose weight are more likely to have acquired a positive sense of themselves, because they've had some academic or athletic success, or some other notable accomplishment. Sometimes they have embarked on a successful romantic relationship. And often parents and other adults in their life focus on their strengths rather than harping on weight and appearance.

The article is a fine bit 'o science writing, worth reading. (The billboard photo is by ktheory on flickr.com)


Posted by Chris Spurgeon at July 15, 2006 04:20 AM