This study uses feedback design to explore the relationship between cognitive effort, usability, and behavior intention. We developed a decision aid, FoodGlance, which help users in making healthy food selection. We created two feedback designs for decision aid. The first feedback design scans the nutrition fact label and displays the information in the form of a pop-up. The second feedback used audio augmented reality along with the pop-up. Our results showed that cognitive effort had an impact on behavior intention; this impact was mediated by usability. However, this relationship was significant only when the task condition required high cognitive effort and had low usability. The two feedback designs significantly reduced cognitive effort in the decision-making process and increased usability. When participants used the pop-up feedback design, the mediating role of usability vanished. When the participant used pop-up with audio feedback, usability was no longer a player in our proposed model.