Weight status misperceptions among UK adults: the use of self-reported vs. measured BMI

BACKGROUND: It has been suggested that a significant proportion of overweight and obese individuals underestimate their weight status and think of themselves as being a healthier weight status than they are. The present study examines the prevalence of weight status misperceptions in a recent sample of UK adults, and tests whether the use of self-reported BMI biases estimation of weight status misperceptions. METHODS: Data came from UK adults who took part in the 2013 Health Survey for England. We examined the proportion of overweight vs. normal weight (categorised using self-reported vs. measured BMI) males and females who perceived their weight as being 'about right', as well as how common this perception was among individuals whose waist circumference (WC) placed them at increased risk of ill health. RESULTS: A large proportion of overweight (according to measured BMI) women (31 %) and men (55 %) perceived their weight as being 'about right' and over half of participants with a WC that placed them at increased risk of future ill health believed their weight was 'about right'. The use of self-reported (vs. measured) BMI resulted in underestimation of the proportion of overweight individuals who identified their weight as 'about right' and overestimation of the number of normal weight individuals believing their weight was 'too heavy'. CONCLUSIONS: A large proportion of UK adults who are overweight misperceive their weight status. The use of self-reported BMI data is likely to produce biased estimates of weight status misperceptions. The use of objectively measured BMI is preferable as it will provide more accurate estimates of weight misperception.