PHOENIX -- New studies that target Americans' expanding waistlines were presented this weekend at the annual meeting of the Obesity Society, an organization of researchers and weight-loss professionals. They include:
Teens' timing can be bad
Girls often become much less physically active during their teen years, but researchers say that is just when they should move into high gear if they want to control their weight.
Scientists at Harvard Medical School in Boston analyzed data on 3,914 females ages 14 to 22. The data were gathered in 2000 and 2001 and from 2003 to 2005. Some of the younger women were gaining weight because they were still growing and maturing. But most of the older women had reached full maturity, and their weight gain was more likely to be unhealthy.
In 2001, about 54% of the young women wanted to lose weight, and 24% were trying to maintain their weight.
About half reported exercising at least once a week, and 14% said they exercised five or more times a week. The duration and intensity varied dramatically, including short bouts of toning exercises, playing soccer, dancing and jogging.
Among the findings:
*The young women gained an average 7 pounds from 2001 to 2005.
*Those who exercised the most -- five or more days a week -- and limited portion sizes gained 3 pounds.
*Those who exercised at least once a week and ate a low-fat diet or limited portion sizes gained about 5 1/2 pounds.
Many girls tend to cut back on activity during puberty because they may not want to sweat or have their hair messed, and that is the worst possible time to stop being active, says Alison Field, associate professor of pediatrics. "The key is to find an activity you like," she says, adding that the habits young women form at this time of their lives may be with them for a lifetime.
Too much 'Joy of Cooking'?
Next time you whip up a classic recipe from Joy of Cooking, consider this: Your dish may have far more calories than the recipe your grandma made from an earlier edition.
Researchers at Cornell Food and Brand Lab reviewed the serving sizes and calorie content of seven editions of the cookbook from 1936 to 2006.
Only 18 recipes have been published continuously during that time, and the average calories per serving increased in 17 of them. Recipes included brownies, sugar cookies, apple pie, macaroni and cheese, beef stroganoff, Spanish rice and goulash.
In 1936, recipes averaged 2,124 calories, with 268 calories per serving. In 2006, the average recipe had 3,052 calories, with 436 calories a serving, researchers found. Increases in fat and sugar and larger servings were cited.
Restaurant and takeout food have increased portions, and they also have increased in recipes, says study co-author Collin Payne, an assistant professor of marketing at New Mexico State University-Las Cruces. The serving size and calorie composition of classic recipes may need to be reduced, he says.
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