Background

Behavioral obesity interventions see little success; few patients lose weight considerably. Being able to predict who would benefit from such programs can reduce stress and inform the development of more effective interventions. Though obesity is equally prevalent in men and women in the U.S., studies tend to include only women. The few studies of gender differences in this context suggest that obesity is associated with different psychological properties in women and men. Therefore, we can’t assume that men and women share the same predictors of weight-loss success. In this study we looked at reward-seeking and recency (tendency to neglect long-term implications when making decisions) as predictors of weight loss in men.

Methods

Male patients (N=30, mean age =58, BMI =39.9) participated in a behavioral weight-loss program offered by the VA for 8 weeks. They met weekly, got weighed, and received information and dietary guidance. Success was defined as losing at least 5% of initial weight. Subjects completed a battery of tasks and questionnaires assessing the aforementioned predictors when they program started. Reward-sensitivity and recency were assessed by the Expectancy-Valence Model, a mathematical model that is applied to the individual’s decision-making pattern, as measured by a laboratory task.

Results

About 15% of participants achieved weight-loss goal. The results suggest that successful male dieters are less affected by recency and reward-seeking in their decision making, compared to unsuccessful dieters. While past studies identified recency as a predictor of weight loss in women as well, reward-seeking appears to be a predictor unique to men.

Conclusions

Studies of obesity in men are scarce. Consistent with the need to increase diversity in obesity research, this study is the first to address predictors of weight loss that are unique to men. More research is needed in order to draw strong conclusions about the predictive power of recency and reward-seeking in this population.