Changes over time in the relationship between weight, body fat, motivation, impulsivity and eating behaviour

University students are at a greater risk of gaining weight compared to others. We explored associations between changes in weight and a set of dispositional constructs related to eating behaviour: motivation, impulsivity, social comparison, and eating styles. We predicted that increases in controlled motivation, impulsivity, uncontrolled eating, emotional eating, and physical appearance comparison would be related to increased weight and body fat.

First year students at a British university completed baseline (n = 196) and three-month (n = 163) measures of impulsivity, physical appearance comparison, motivation for following a healthy diet, eating styles, weight and body fat. Baseline-follow-up changes in these constructs were computed and subjected to cluster analysis.

Four participant groups were identified according to similarities in the way these constructs evolved over time. The Losing and Gaining groups tended to show opposing changes in key variables (physical appearance comparison, uncontrolled eating, motivation, weight, and percentage of body fat). Interestingly, two groups showed no change in weight and body fat but evidenced unique changes in key variables, indicating that individuals can have different psychological profiles but still maintain their weight.

The study highlighted how stable weight maintenance arises from sets of interdependent constructs rather than variables in isolation, as well as emphasizing a need to take a person-centred approach to examining those at risk of weight gain and in developing interventions.