John Neumann for redOrbit.com – Your Universe Online
Two different studies by European and US researchers concluded that obese adults who are otherwise physically fit had no greater risk of dying prematurely than those with a normal body mass index (BMI), according to research partially funded by the US National Institutes of Health (NIH) and soft-drink maker Coca-Cola.
The findings show there is a subset of obese people who are metabolically healthy, with no symptoms of insulin resistance, diabetes and high cholesterol and who have a high level of fitness as measured by how well the heart and lungs perform, than other obese people, writes Kristen Hallam for Business Week.
This subset registers no detrimental health effects, and doctors should bear this in mind when considering what, if any, interventions are required, say the researchers.
The results reverse decades of public health messages, supported by research saying otherwise, that obesity can accelerate the development of heart disease, diabetes and cancer and shrink lifespans.
Three European researchers who weren´t involved in the two studies wrote in an editorial that accompanied the results in the European Heart Journal today.
“The prevailing wisdom holds that being slim must be generally good for you,” Stephan von Haehling, Oliver Hartmann and Stefan Anker wrote in the editorial. “Obesity may carry a benefit up to a certain degree, and it should be recognized that obesity is not necessarily associated with abnormal metabolic function.”
Amy Thompson, a senior cardiac nurse at the British Heart Foundation explains the studies should serve as reminders that carrying fat around the belly and how fat affects your fitness may be more important than the numbers on the scale.
“In the majority of cases, obesity is an undeniable risk factor for developing coronary heart disease,” Thompson said in a statement. “However, these studies remind us that it is not always your weight that´s important, but where you carry fat and also how it affects your health and fitness.”
More than 40,000 study participants were followed between 1979 and 2003, and completed a detailed questionnaire, including information on their medical and lifestyle history, along with a physical examination that included a treadmill test to assess cardio-respiratory fitness and measurements of height, weight, waist circumference, and their percentage of body fat. Blood pressure, cholesterol and fasting glucose levels were also measured.
Dr. Francisco Ortega (PhD) currently a research associate affiliated to the Department of Physical Activity and Sport, University of Granada (Spain), and at the Department of Biosciences and Nutrition, Karolinska Institutet (Stockholm, Sweden) headed the study. He and his colleagues found that 46 percent of the obese participants were metabolically healthy.
After adjusting for several confounding factors, including fitness, the metabolically healthy but obese people had a 38 percent lower risk of death from any cause than their metabolically unhealthy obese peers, while no significant difference was seen between the metabolically healthy but obese and the metabolically healthy, normal weight participants.
The risk of developing or dying from cardiovascular disease or cancer was reduced by between 30-50 percent for the metabolically healthy but obese people, and there were no significant differences observed between them and the metabolically healthy, normal weight participants.
A second study which analyzed data from 64,000 heart patients in Sweden provides new evidence supporting the ℠obesity paradox´, writes Jenny Hope for Daily Mail UK. The obesity paradox means fat patients with heart disease have ℠paradoxically´ better outcomes and survival than thinner patients. The greatest risk of dying was among the underweight and morbidly obese, who have the very highest levels of obesity.
William Zoghbi, president of the American College of Cardiology, responded that the results aren´t a complete surprise, because in real life, not all obese people have the same prognosis.
“This provides evidence that this is the case,” said Zoghbi. “Obesity is still a risk, but with gradation. Personally, I´d encourage fitness in all individuals, but it´s more important in a person who´s overweight or obese.”