A little bit of extra body weight may actually help us live longer, according to a study published Jan. 1 in The Journal of the American Medical Association.
The study, which looked at the link between Body Mass Index (BMI) and death, found that adults who were slightly overweight, within the BMI range of 25-30, had “[statistically] significantly lower all-cause mortality,” the study stated.
Specifically, those who fell into a BMI range of 25-30 had six per cent lower risk of death than that of people who fell within a “healthy” BMI range of 18.5-25. However, obese patients had a risk that was 20 percent higher than those in the healthy range.
The study didn’t specifically point to any single cause for their findings, nor did it measure the links between BMI and any specific disease, but stated that overweight people may receive earlier and better medical treatment for illness.
Researchers also added that a small amount of body fat could have some protective effects.
Similar results have been found in previous studies, which have been nicknamed the “obesity paradox” by medical researchers.
Jean-Marie Berthelot authored a similar study looking at the link between BMI and mortality among Canadians for the Obesity Journal. Berthelot also found a lower risk of death for those classified as overweight, however he added that this did not mean overweight people lead healthier lives.
“Obesity is very well documented to be associated with specific diseases and with morbidity,” Berthelot said.
“Maybe you won’t die sooner, but it doesn’t mean you will have an independent life . . . from a health perspective, too much weight is still not good.”
As well, people who have long-term diseases or illness may have a lower BMI if their affliction has caused them to lose weight. According to research by University of Guelph professor John Cranfield, smokers also tend to have a lower BMI.
Walter Willett, a professor from Harvard University’s nutrition school, told NPR the study was a “pile of rubbish.”
He said a proper study needed to include data on fitness and pre-existing disease instead of just BMI.
“We have a huge amount of other literature showing that people who gain weight or are overweight have increased risk of diabetes, heart disease, stroke, many cancers and many other conditions,” Willett said.
The American Medical Association study, however, claimed that adjusting past research to account for pre-existing illnesses produced little effect.
Despite the press, Berthelot says the findings aren’t as controversial as they may seem.
He said that while the studies “in some way challenge the medical knowledge and the common sense knowledge about weight and obesity,” they must be placed in their context.
“Obesity is more than mortality, and the message that obesity is bad for you is still not rejected by these articles.”
Berthelot added that the current classifications for healthy and overweight BMIs, as developed by the World Health Organization, are meant for global use and may not be representative of health in the Western world where access to food and nourishment is easier.
According to Statistics Canada, 34.2 per cent of Canadians are overweight by BMI measurements, and 18.1 per cent are obese.
The American Medical Association study compiled results of many different journal articles around the world and had a sample size of more than 2.8 million people.
