So What Is a Healthy Weight?

It may be just one more wave in the tsunami of the obesity epidemic. Two British psychologists recently reported that exposure to obesity can change one’s perception of overweight and obesity. The authors’ study results showed that with exposure, people come to view obese individuals as being at a healthier weight and less likely to need to change their weight (Int J Obesity. 2014; 38:663).

Drs. E. Robinson and T. C. Kirkham, of the University of Liverpool, used three experiments to see if exposure to photographs of either obese or healthy weight young men had an impact on visual judgments of “healthy weight.” The researchers wondered if social environment provided the definition of “normal,” and as obesity becomes more prevalent, would individuals change their perception of what is a healthy weight?

In what was advertised as “a perception study,” three groups of undergraduate males viewed 10 photographs and made non-weight-based rating of the photos of either obese (BMI >30 kg/m²) or healthy weight men (BMIs from18.5 to 24.9 kg/m²) or a set of neutral everyday objects (control condition). The participants then completed a questionnaire that involved rating non-weight-based items about 10 photos of either obese or healthy weight young males. Participants then rated a photo of an obese male and selected what they thought the average weight of a young male was from a range of body weight possibilities.

In the second experiment, using the same photographs, 11 male and 66 female undergraduates were tested with a paper-based questionnaire administered during a psychology lecture. The students rated the mood of the individual in each photo (happy, sad, or angry), and then rated the perceived health of the overweight model. As before, all participants were within healthy weight ranges. After exposure to photographs of obese males compared with photos of males of healthy weight, participants rated the overweight model as having a healthier weight.

In experiment 3, the authors attempted to find if obesity exposure changed perceptions about the need for an overweight person to lose weight. The study group included 50 females and 30 males recruited from a university campus. The authors used the same method as in experiment 2 but this time conducted the study in a laboratory setting. The body weight norm question was replaced with the following statement, “This person should consider losing weight.” After their exposure to obese photos, participants rated the overweight model as being at a healthier weight and were less apt to believe that the overweight model needed to lose weight..

The authors’ findings provide direct experimental evidence to support suggestions from epidemiological studies that changes to societal weight norms may influence perceptions about what is “normal weight.” These results have complex implications from an obesity perspective; they suggest that increasing BMI may lead to diminished urgency about weight management, which might carry public health implications. On the other hand, increased acceptance of higher body weight might lessen body dissatisfaction and could diminish risk for disordered eating.