The connection between schooling and health is well documented. An importan
t empirical issue that needs to be examined, however, is whether schooling'
s effects are due to individual health knowledge differences. This empirica
l study examines this issue with an increasingly important health indicator
, obesity. Since provision of health knowledge is a major tool of public ag
encies promoting health, this empirical study uses a new direct measure of
health knowledge to test this hypothesis. The results show that knowledge i
s inversely related to the probability that an individual is obese. Schooli
ng's effects on relative weight and the probability of being obese are expl
ained by differences in knowledge. This result may imply that schooling's e
ffect on the allocative efficiency of the household production of health is
the main reason schooling is linked to health behaviour. The result also m
ay imply that the most effective method of health education is to highlight
the disease element of poor dietary habits and health. More importantly, t
he simulations conducted suggest positive returns to knowledge based on imp
rovements in the probability estimates.