A new study published on Jan. 3 in JAMA provides some additional insight on the actual risk of mortality based on body mass index (BMI). Contrary to public opinion, it appears that being overweight does not actually lead to higher mortality rates and instead, may actually reduce the risk of mortality.
Compared to normal weight individuals (BMI 18.5-25), those who were considered overweight based on their BMI were significantly less likely to die from a variety of causes. Individuals who met criteria for grade 1 obesity (BMI 30-35) were at no greater mortality risk than those who were normal weight. The only increased risk of mortality came for individuals with a BMI over 35, constituting grades 2 and 3 of obesity.
These results are in line with many other recent studies, providing support for the concept. Another article, published in November, looked at BMI in relation to 30 day post surgery mortality. Patients with lower BMIs were at a 40 percent increased risk of mortality compared to patients who were moderately overweight.
These findings of survival benefits for overweight and moderately obese individuals has become known as the "obesity paradox" since our society expects poorer outcomes to be linked with obesity. However, that is not always the case and one reason might be due to the benefits of having a higher metabolic reserve that can help fight disease and aid in survival.
Perhaps the most important concept, however, is that being overweight may not be the most critical health factor for patients and that in some cases, it may serve as a protective factor. Being overweight or moderately obese is pathologized, but sometimes it may not confer greater risk. The stigma attributed to having a higher body weight should be tempered with the understanding that it may not be unhealthy, especially if the person is eating healthfully and exercising regularly.