Self-Reported Perceptions and Practices of University Students Who Adhere to Special Restrictive Diets: A Pilot Study

Thesis (Master's)--University of Washington, 2017-03Background: The Dietary Guidelines for Americans recommends consuming a variety of foods from each of the major food groups to support a healthy diet. However, usage of special restrictive diets that exclude specific foods or food groups appears to be common. Some studies suggest restrictive diets may have negative nutritional, monetary, and psycho-social ramifications. Given these potential challenges, it is important to learn more about special restrictive diet usage and the perceptions and practices of individuals following these diets to understand how to more effectively engage with these individuals. Objective: This cross-sectional study assessed what types of special restrictive diets a sample of university students self-reported to follow. The study further investigated associations of different restrictive diet types with a) demographic characteristics; b) dietary perceptions; c) importance of food issues during food choice; and d) frequency of considering food issues during food purchase. This study also investigated associations between the perceived importance of food issues during food choice and the frequency of considering the same respective food issues during food purchase. Methods: An anonymous, web-based survey was conducted amongst 38 University of Washington students who self-reported to follow a special restrictive diet. Associations between variables were tested by using a Fisher’s exact test of proportions. Results: The most predominant self-reported special restrictive diets amongst this university student population were the dairy-free (50%) and vegan or vegetarian diets (39.5%), followed by the gluten-free (31.6%), “other”-type (31.6%), wheat-free (18.4%), and paleolithic-type (13.2%) diets. Half of respondents followed two or more types of restrictive diets. Over three-quarters of those on a dairy-free diet reported to be an undergraduate student, whereas 22.2% were graduate or professional students (p=0.02). No one on a paleolithic-type diet agreed that the nutrition recommendations of health/nutrition experts are sound and can be trusted compared to 80% who disagreed and 20% who felt neutral (p=0.01). The majority (75%) of gluten-free dieters agreed that the US food supply is safe (p=0.04). None of those on a vegan/vegetarian diet agreed that food manufacturers and the agricultural system are trustworthy and open about their practices (p=0.02). Genetic modification of food was rated as important during food choice by 53.3% of vegan/vegetarian diet followers compared to 26.7% who felt neutral, and the 20% who rated this as unimportant (p=0.03). More (66.7%) participants on an “other”-type diet reported to sometimes take food processing and preparation contamination into consideration during food purchase than they reported to frequently (33.3%) consider this issue (p=0.04). Across all issues, the reported importance of each food issue (i.e., food additives, agricultural contamination, and food processing and preparation contamination) during food choice was significantly associated with the frequency of considering the same respective food issue during food purchase (p < 0.05, each). Conclusion: This sample of university students engaged in a variety of special restrictive diets. Association testing showed specific diet types to be associated with demographic, dietary perception and dietary practice variables. Also, the associations found between the perceived importance of food issues during food choice and the frequency of considering the same food issues during food purchase imply a potential link between food issue perceptions and behavior. Clinicians and public health professionals could benefit from the results of this study in supporting patient and population nutritional health. These results could also be used to inform larger, well-designed studies that aim to further elucidate these associations and directionality between diet type and perception variables