Inaccurate recognition of weight status is a threat to healthy weight control. Until the mid-1990s, the emphasis was on young women’s tendency to identify themselves as overweight despite a healthy body size,1 2 3
and concern focused primarily on the risks of eating disorders. With rates of anorexia remaining stable4
but obesity rates rising inexorably,5 6
attention has now turned to awareness of weight status among those who are overweight or obese. A considerable proportion of overweight adults—men in particular—do not recognise that their body weight is too high,7 8 9
and many parents fail to recognise that their children are overweight.10 11 12
The clinical categories “overweight” and “obese,” defined by BMI (body mass index) thresholds of over 25 and over 30, respectively, are used universally by health professionals to evaluate risks associated with excess body weight. Lay definitions of these terms, however, might differ from those of clinicians, and such discrepancies can present a barrier to communication between the health profession and the public. The public’s weight perceptions are probably less rigidly defined and influenced by perceptions of acceptable weight related to specific cultural and social groups.13 14 15
Changes in the social environment over recent years could have affected weight perceptions in several ways. Increased attention to the “obesity epidemic” and publicity channelled through the media and health professionals to encourage appropriate action for weight control16 17
might be expected to promote recognition of overweight. There has also been an emphasis on positive body images for young women, which should have reduced inaccurate perceptions of overweight among normal weight women. On this basis, weight recognition should have become more accurate.
Media reports about body weight, however, often use images of severe obesity, which could give the impression that extremely high weights are required to meet medical criteria for overweight. In addition, increases in adiposity in the population might have “normalised” overweight, leading to increased acceptance of body fat and reduced recognition of excess weight. The social comparison effects might also mean that fewer normal weight individuals incorrectly perceive themselves to be overweight. On this basis, recognition of overweight might be expected to be worse in overweight and obese individuals.
Accuracy in self diagnosing overweight can be approached with the diagnostic concepts of sensitivity and specificity.18
Sensitivity is the proportion of truly overweight people who identify themselves as such, while specificity is the proportion of people who are not overweight who identify themselves correctly as not overweight. If the combined emphasis on public awareness of the risks of obesity and promotion of a healthy body image in young women has been successful, then both sensitivity and specificity of self diagnosed overweight should have increased. On the other hand, if social comparison processes have led to normalisation of overweight, any increase in specificity might have been accompanied by a decrease in sensitivity.
We investigated changes in public perception of overweight over an eight year period, and assessed effects on the self diagnostic abilities of overweight and normal weight British adults.