Life satisfaction and body mass index: estimating the monetary value of achieving optimal body weight.

According to the World Health Organization, obesity is one of the greatest public-health challenges of the 21st century. Body weight is also known to affect individuals' self-esteem and interpersonal relationships, including romantic ones. We estimate the "utility-maximizing" Body Mass Index (BMI) and calculate the implied monetary value of changes in both individual and spousal BMI, using the compensating income variation method and data from the Swiss Household Panel. We employ the Oster's method (Oster, 2019) to estimate the degree of omitted variable bias in the effect of BMI on life satisfaction. Results suggest that the optimal own BMI is 27.1 and 20.1 for men and women, respectively. The annual value of reaching optimal weight ranges from $7069 for women with underweight to $88,709 for women with obesity and between $95,165 for men with underweight to $32,644 for men with obesity. On average, women value reduction in their own BMI about four times higher than reduction in their spouse's BMI. Men, on the other hand, value a reduction in their spouse's BMI almost twice as much compared to a reduction in their own BMI. This highlights important gender differences and relative effects based on spousal BMI.