Severe obesity is associated with a loss of 8–10 years of life, and moderate obesity is associated with 2–4 lost years, according to a very large study.
“Excess weight shortens human life span. In countries like Britain and America, weighing a third more than the optimum shortens life span by about 3 years. For most people, a third more than the optimum means carrying 20–30 kg [50–60 pounds] of excess weight. If you are becoming overweight or obese, avoiding further weight gain could well add years to your life,” Dr. Gary Whitlock of the University of Oxford (England), study investigator, said in a statement.
The analysis combined prospectively collected data from 894,576 adults who participated in 57 separate studies, mostly in Europe, Israel, the United States, and Australia. Participants were 46 years old on average when recruited, and were followed for an average of 13 years. The investigators discarded the first 5 years of mortality data to limit the effects of preexisting disease on the analysis. Not counting that 5-year period, the participants were followed for 6.5 million person-years (Lancet 2009 March 18 [doi:10.1016/S0140–6736(09)60318–4]).
The mortality rate was lowest in participants with a body mass index between 22.5 and 25 kg/m
Low BMI also was associated with excess mortality. Men with a BMI between 15 and 17.5 kg/m
Higher BMI was associated with higher rates of virtually all causes of mortality including ischemic heart disease, stroke, other vascular disease, diabetes, kidney disease, liver disease, respiratory disease, and neoplastic disease.
The association between BMI and cancer was much weaker than that between BMI and vascular disease, however. Each 5-kg/m
The investigators emphasized that prevention of excess weight gain would likely be more effective than dieting to lose weight.
They wrote, “In adult life, it may be easier to avoid substantial weight gain than to lose that weight once it has been gained. By avoiding a further increase from 28 kg/m
The many coauthors of this study were part of the Prospective Studies Collaboration of the Clinical Trial Service Unit of the University of Oxford. The collaboration was supported by the UK Medical Research Council, the British Heart Foundation, Cancer Research UK, the EU BIOMED Program, and the National Institute on Aging.