Overweight Korean Adolescents and Academic Achievement
Cho, S., D. M. Lambert, Kim, H., and Kim, S. G..  2009.  Journal of Family and Economic Issues 30:126-136.

Abstract:
The relationship between academic achievement and being overweight among South Korean high school students was examined. Data used in the regression were from the Korean Education and Employment Panel Survey. The theoretical framework that poor school performance increases the risk of adolescentsí» being overweight, which, in turn, causes poor school performance, was supported. With no other direct or indirect association between weight and achievement, an overweight high school studentí»s poor performance in school was assumed to be a function of the psychosocial well-being variables and self-concern about weight. A simultaneous-equation regression model that endogenized the likelihood an individual is classified as overweight (a binary variable) and the performance of that individual on the College Scholastic Ability Test (CSAT) incorporates the unobserved psychosocial well-being correlated with both school grades and being overweight.