Much previous research has shown the health belief model to be effective in explaining social-cognitive processes that lead to attitude-behavior consistency across a wide variety of health-related behaviors. The health belief model, like other social-cognitive models that rely upon
the hierarchy-of-effects principle, presumes rationality between beliefs and attitudes, attitudes and intentions, and intentions and behavior for volitional behavior. It was found, for food intake behavior, that rationality is not achieved unless respondents have a high threshold level of
“how-to” and “awareness” nutrition knowledge. Thus, as with ill-formed intentions, ill-formed knowledge (i.e., beliefs) can lead to nonrationality in volitional behavior.