Explaining a Health Problem — Obesity and Addiction

To show how the biopsychosocial model works in practice, health psychologists examine specific health problems and the risk factors that explain them. A clear example is obesity, defined medically as a body mass index of 30 or above, and closely related to disorders of eating and, more broadly, to models of addiction. No single cause explains why some people develop obesity; instead, biological, cognitive, and sociocultural risk factors combine, illustrating exactly why a multi-level explanation is needed.

Biological risk factors provide part of the story. Twin and adoption studies show that body weight is substantially heritable: adopted children tend to resemble their biological rather than their adoptive parents in weight, suggesting genes influence how efficiently the body stores fat a