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Carrying a little extra weight? That may not be a bad thing, study says

Published: Sunday, Sept. 22 2013 3:20 p.m. MDT

Krista Perkins takes her daily walk during her lunch break in Salt Lake City on Thursday, Sept. 19, 2013.

Laura Seitz, Deseret News

SALT LAKE CITY — Krista Perkins tries to eat clean, which includes eating raw or steamed vegetables, unprocessed meat and chicken and avoiding processed food.

She walks at least 10,000 steps every day.

"The biggest thing as far as healthy for me is eating right, making sure I exercise and am physically active," she said.

Her body mass index — calculated by dividing weight in kilograms by height in meters squared — hovers just above 35. In her youth she logged 15 hours of exercise a week while training for Karate, but her BMI stayed at about 27.

Perkins is among the approximately 70 percent of Americans older than 20 who are considered overweight or obese, according to data from the Centers for Disease Control and Prevention. But a recent study suggests a little extra weight may not be a bad thing.

A study published in the Journal of the American Medical Association indicated that those who are overweight (BMI range of 25 to 29.9) or mildly obese (BMI range of 30 to 34.9) live just as long or longer than those with an average BMI (18.5 to 24.9.)

"The article demonstrates that it is only at more extreme levels of obesity that weight is important. In the overweight range, shape matters more and the risk is on the apples (higher waist-to-height ratio,) and not the pears, (lower waist-to-height ratio)," Margaret Ashwell, who heads Ashwell Associates, a group that researches health and nutrition, among other things, said in an email.

This is counter to the perceptions that healthy bodies are slim bodies.

"Sometimes slim people aren't eating that well," Patrice Isabella, a registered dietitian with the Utah Department of Health, said.

One benefit to being overweight, she said, is if "they get sick and lose weight, they have some stored energy reserves that lean people do not have, and are less likely to lose lean body mass in the event of illness."

BMI study

The study analyzed 97 medical articles that used BMI to measure hazard ratios for deaths. This was a combined sample size of more than 2.88 million individuals and more than 270 000 deaths. It followed BMI standards set by the Heart, Lung and Blood Institute. Respondents were from United States, Canada, Europe, Australia, China or Taiwan, Japan, Brazil, Israel, India and Mexico.

The looked at 53 adequately adjusted studies separately from 34 studies that "overadjusted" for factors like hypertension and the 10 that had not yet adjusted for smoking or age.

The article "summarized information about mortality and standard categories of body mass index and was not intended to cover other topics, such as morbidity, specific causes of death, non-standard BMI categories or other measures," Katherine M. Flegal, one of the authors of the study, said.

The data from the study misses the mark in a few areas, Isabella points out. First, it is self-reported, which means some people may have reported inaccurate information. It also did not control for diet or physical activity or inactivity.

There also are limitations within the BMI measurement itself, she said.

"I think BMI isn't all it's cracked up to be," she said. "It's a screening tool and screening needs to be followed up with other measures."

Healthcare providers need consider more than BMI, but need to look at the distribution of fat instead, Isabella said.

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