Based on my understanding, deductive or called a "top-down" approach is most appropriate research approach for my PTA topic. This is because deductive approach works from the more general to the more specific, for example I want to know the main reason that young customers would more prefer on fast food in their eating habits. In this situation, I would like to know more specifically about the effects when consumed too much fast food.
Deductive approach has gone through theory, hypothesis, observation and confirmation. Apart from that, by using the deductive research I think I can starts with a model to forms a hypothesis in order to gather data or information to test the hypothesis whether accept the hypothesis or reject it. Therefore, deductive approach often linked to datasets, surveys or quantitative analysis to access the conclusions and recommendations.