When does dietary knowledge matter to obesity and overweight prevention?

► Expected food availability (EFA) underlies the effects of dietary knowledge (DK). ► DK affects mainly the quantity of diet among the overweight when EFA increases. ► DK affects mainly the quality of diet among the non-overweight when EFA decreases. ► Using conventional models, the estimated effects of DK tend to be smaller. ► When EFA increases dietary education may be more effective than indicated before.