We argue that despite inconsistencies in the definition , patterns across studies clearly show that healthy obesity is a state of intermediate disease risk .
Expert commentary : Given the current state of population -level evidence , we conclude that obesity and metabolic dysfunction are inseparable and that healthy obesity is best viewed only as a state of relative health but not of absolute health .
INTRODUCTION Obesity is a top public health priority but interventions to reverse the condition have had limited success .
About one-in-three obese adults are free of metabolic risk factor clustering and are considered ' healthy ' , and much attention has focused on the implication s of this state for obesity management .
Body-mass index and cause-specific mortality in 900 000 adults: collaborative analyses of 57 prospective studies
Summary Background The main associations of body-mass index ( BMI ) with overall and cause-specific mortality can best be assessed by long-term prospect i ve follow-up of large numbers of people . The Prospect i ve Studies Collaboration aim ed to investigate these associations by sharing data from many studies . Methods Collaborative analyses were undertaken of  baseline BMI versus mortality  in 57 prospect i ve studies with 894 576 participants , mostly in western Europe and North America ( 61 % [ n=541 452 ] male , mean recruitment age 46 [ SD 11 ] years , median recruitment year 1979 [ IQR 1975–85 ] , mean BMI 25 [ SD 4 ] kg/m2 ) . The analyses were adjusted for age , sex , smoking status , and study . To limit reverse causality , the first 5 years of follow-up were excluded , leaving 66 552 deaths of known cause during a mean of 8 ( SD 6 ) further years of follow-up ( mean age at death 67 [ SD 10 ] years ) : 30 416 vascular ; 2070 diabetic , renal or hepatic ; 22 592 neoplastic ; 3770 respiratory ; 7704 other . Findings In both sexes , mortality was lowest at about 22·5–25 kg/m2 . Above this range , positive associations were recorded for several specific causes and inverse associations for none , the absolute excess risks for higher BMI and smoking were roughly additive , and each 5 kg/m2 higher BMI was on average associated with about 30 % higher overall mortality ( hazard ratio per 5 kg/m2 [ HR ] 1·29 [ 95 % CI 1·27–1·32 ] ) : 40 % for vascular mortality ( HR 1·41 [ 1·37–1·45 ] ) ; 60–120 % for diabetic , renal , and hepatic mortality ( HRs 2·16 [ 1·89–2·46 ] , 1·59 [ 1·27–1·99 ] , and 1·82 [ 1·59–2·09 ] , respectively ) ; 10 % for neoplastic mortality ( HR 1·10 [ 1·06–1·15 ] ) ; and 20 % for respiratory and for all other mortality ( HRs 1·20 [ 1·07–1·34 ] and 1·20 [ 1·16–1·25 ] , respectively ) . Below the range 22·5–25 kg/m2 , BMI was associated inversely with overall mortality , mainly because of strong inverse associations with respiratory disease and lung cancer . These inverse associations were much stronger for smokers than for non-smokers , despite cigarette consumption per smoker varying little with BMI . Interpretation Although other anthropometric measures ( eg , waist circumference , waist-to-hip ratio ) could well add extra information to BMI , and BMI to them , BMI is in itself a strong predictor of overall mortality both above and below the apparent optimum of about 22·5–25 kg/m2 . The progressive excess mortality above this range is due mainly to vascular disease and is probably largely causal . At 30–35 kg/m2 , median survival is reduced by 2–4 years ; at 40–45 kg/m2 , it is reduced by 8–10 years ( which is comparable with the effects of smoking ) . The definite excess mortality below 22·5 kg/m2 is due mainly to smoking-related diseases , and is not fully explained . Funding UK Medical Research Council , British Heart Foundation , Cancer Research UK , EU BIOMED programme , US National Institute on Aging , and Clinical Trial Service Unit ( Oxford , UK )
We argue that despite inconsistencies in the definition , patterns across studies clearly show that healthy obesity is a state of intermediate disease risk .
Expert commentary : Given the current state of population -level evidence , we conclude that obesity and metabolic dysfunction are inseparable and that healthy obesity is best viewed only as a state of relative health but not of absolute health .
INTRODUCTION Obesity is a top public health priority but interventions to reverse the condition have had limited success .
About one-in-three obese adults are free of metabolic risk factor clustering and are considered ' healthy ' , and much attention has focused on the implication s of this state for obesity management .