Why do people want to lose weight? While this seems like an obvious question, it does merit answering. There are two major reasons: health concerns and appearance. Being obese increases the risk of suffering from many diseases (e.g.: diabetes). On the appearance side, individuals may experience social pressure to lose (or possibly gain) weight. Further, individuals may want to maintain a healthy body appearance to attract a mate.

Jeffery Sobal is an expert in obesity studies. According to his 2003 study, activities which directly affect weight are caloric intake, physical activity and smoking.

One of the more interesting questions is how an individual’s marriage status affects obesity. It is generally found that–even controlling for age and other covariates–married individuals are more likely to be overweight than non-married individuals. Why is this the case. Sobal cites some studies which attempt to explain this.

After citing all this evidence, Sobal and co-authors state 4 hyptotheses to test:

Marital trajectories that are stable are related to stable body weights, marital trajectories entering marriage are related to weight gain, marital trajectories dissolving marriage are related to weight loss, marital trajectories involving the death of a spouse are related to weight loss.

Sobal uses data from from the National Health and Nutritional Examination Survey (NHANES I). A 10 year follow up survey of the participants is collected in the National Health and Nutrition Epidemiological Followup Survey (NHEFS). The authors use an OLS specification with a lagged dependent variable (i.e., lagged BMI) in order to estimate the impact of marital status on weight. Sobal, Rauschenbach and Frongillo conclude the following:

Stable marital trajectories were not associated with significant weight changes, except for weight loss among men who remained separated/divorced.

Marital trajectories involving entry into marriage were associated with weight gain among women, but not among men.

Marital trajectories involving dissolving marriages were associated with weight loss among men, but not women.

Marital trajectories involving death of a spouse were associated with weight loss among men, but not women.

Marital and other demographic characteristics were better predictors of weight loss than weight gain.