Sleep loss,air conditioning make us fat
Fast food meals and TV time shouldn't take all the blame for the U.S. obesity problem, according to a research review published Tuesday.
In fact, a group of researchers contend, a number of aspects of modern living -- from lack of sleep to exposure to living with air conditioning -- may be feeding Americans' weight woes.
Writing in the International Journal of Obesity, they argue that obesity research and prevention efforts need to look beyond the "Big Two" -- food industry practices, like beefed-up portion sizes and added sugar; and reduced physical activity from factors such as cuts in school gym classes.
That's not to say that diet and exercise aren't important. However, the evidence linking obesity to food industry marketing and lack of gym class is circumstantial.
Lack of sleep is one, they say. Research in animals and humans suggests that chronic sleep deprivation boosts appetite and eating, and studies also show that U.S. adults and children are sleeping less than they used to. In recent decades, adults have gone from sleeping for an average of 9 hours to about 7 hours, the researchers point out.
Another factor potentially weighing Americans down is air conditioning. The body burns calories when forced to regulate its own temperature, and people tend to eat less in hot, humid weather.
The report cites 10 potential obesity risk factors in all, including: increased rates of older mothers, whose children may be more prone to excess weight gain; a range of medications, such as antidepressants, which can promote weight gain; and a decrease in smoking rates, because people often gain weight when they quit and the absence of nicotine, an appetite suppressant.
No one is suggesting that people should stop taking their prescriptions, keep smoking or swelter in the July sun, according to the researcher Allison. When it comes to any one person's weight, he said, "what ultimately matters is calorie intake and calorie expenditure."