A few extra pounds may tack on a few additional years to a person's lifespan, surprising new research suggests.
The study found people who were deemed slightly overweight were less likely to die a premature death than normal weight people. However, study participants who were obese were significantly more likely to die than their normal weight counterparts, which suggests being a bit overweight can be a good thing.
"Maybe heavier people present to the doctor earlier, or get screened more often," explained study author Katherine Flegal, a senior research scientist at the Centers for Disease Control and Prevention, to HealthDay. "Heavier people may be more likely to be treated according to guidelines, or fat itself may be cardioprotective, or someone who is heavier might be more resilient and better able to stand a shock to their system."
Obesity is often considered America's biggest public health crisis, with dramatic rises in rates over recent decades. More than two-thirds of U.S. adults are considered overweight or obese according to CDC estimates -- nearly 69 percent -- and more than one-third of children and adolescents between ages 2 and 19 are overweight or obese.
Those statistics are measured in terms of body mass index (BMI), a ratio calculated by a person's weight and height that's used as a measure of weight for the general population. According to the CDC, adults with a BMI between 18.5 and 24.9 are considered normal weight, those who have a BMI 25 to 29.9 are overweight, and adults with a BMI of 30 and above are considered obese.
The ballooning obesity epidemic has been linked to upticks in heart disease, Type 2 diabetes, strokes, certain types of cancer and other ailments linked to not maintaining a healthy weight. Some recent research even reports rising rates of chronic disease in overweight and obese young adults and teens.
The new study, published Jan. 1 in the Journal of the American Medical Association, found that obesity could contribute to an early death. Researchers analyzed almost 100 studies that included about 3 million adults to estimate all-cause mortality -- or chances of dying from any cause prematurely - in people who were normal weight, overweight or certain grades of obesity. Grade 1 obesity was defined as a BMI from 30 to less than 35, and grades 2 and 3 obesity were measures of obesity with a BMI greater than 35. Researchers found compared to overweight individuals, all obese groups combined were 18 percent more likely to die an early death than normal weight people, and individuals with grades 2 and 3 obesity were 29 percent more likely to die.
However, the big surprise came when overweight individuals were found to be 6 percent less likely to die prematurely than normal-weight ones, and people with grade 1 obesity were 5 percent less likely to die than normal weight folks.
In an accompanying editorial published in the same journal issue, Dr. Steven B. Heymsfield and Dr. William T. Cefalu of the Pennington Biomedical Research Center in Baton Rouge, La., wrote that small amounts of excess fat may provide needed energy reserves to fight off certain illnesses and offer beneficial effects for recovering from some types of traumatic injuries. They said these effects that should be examined for future studies.
Regardless of the conclusions reached, the study's authors won't advise normal weight individuals to pack on extra pounds.
"Our goal is really to summarize existing information and not conclude what people should do, other than follow good health practices, no matter what their weight," Flegal told the Los Angeles Times. Her team also published a study in 2005 that concluded overweight people had lower mortality.
Other researchers not involved in the study have slammed the implications that carrying a bit of extra weight can be protective.
"This is an even greater pile of rubbish" than the 2005 study, Dr. Walter Willett chair of the nutrition department at the Harvard School of Public Health, told The Associated Press.Other experts questioned the study's methodology, noting some of thin people included may have had serious diseases that took away their weight, such as cancer, or have been smokers.
Dr. David Katz, the director of the Yale University Medical School Prevention Research Center, told HealthDay the study presents complex messages but he notes that it only looked at death rates, not disease rates, so overweight people may be living sicker.
"It may well be being overweight does increase the risk of such conditions as Type 2 diabetes, or medication use for cardiac risk factors, without increasing mortality," he said.