The purpose of this thesis was to establish the importance of cognitive factors in the ability to follow therapeutic diets by examining participants’ reading behaviours when shown food labels. In two laboratory experiments, 64 undergraduate students were asked to repeatedly make decisions about the safety of foods that did or did not contain specified allergen targets. Mock food labels were presented in randomized and intermixed orders, with each of 30 products being presented 15 times. At each presentation students were able to make their safety judgement with or without consulting the food ingredient list on the label. With repetition of products, participants traded the certainty of verification for the facility of using memory. Mean target accuracy did not reach 100% implying limitations to people’s reading accuracy, learning, and judgements about that learning. The findings from this study suggest that people probably choose not to read food labels as often as they should and miss seeing target ingredients when they are consulting the label.