Date of Award:


Document Type:


Degree Name:

Doctor of Philosophy (PhD)


Nutrition, Dietetics, and Food Sciences

Committee Chair(s)

Heidi J. Wengreen


Heidi J. Wengreen


Maryellen McClain-Verdoes


Mateja Savoie-Roskos


Tyler Renshaw


Julie Gast


Orthorexia Nervosa (ON) is a relatively new term used to describe individuals who place an excessive value on consuming a “pure” or healthful diet, so much so that their psychological, and potentially physical, health is negatively affected. ON is driven by a focus of consuming high-quality foods rather than limiting the quantity of food. This has sometimes been referred to as “clean eating”, or only consuming “clean” foods. A commonality between ON and other eating disorders (EDs) is that the behaviors are rooted in restriction, where an individual with ON would focus on restricting specific foods, or even entire food groups. The overall objective of the research studies included in this dissertation was to investigate the behaviors associated with ON in young adults and adolescents, and to implement and evaluate the effectiveness of a program for adolescents designed to decrease these behaviors.

The first study investigated the relationship between high or low amounts of nutrition knowledge, how interested an individual was in the subject of nutrition, and ON behaviors. Results of this study show that those who indicate they are more interested in the subject of nutrition may be at a higher risk for practicing behaviors associated with ON, while those who have greater amounts of nutrition knowledge tend to be at a lower risk. Next, given the scarcity of research of this disorder in adolescent populations, the second study evaluated a test originally designed to measure ON behaviors in adults to determine if it was appropriate for use in adolescents. A secondary aim of this study was to explore gender differences in how adolescents think and talk about food and nutrition. Results showed that with minor modifications to several words used in the tool, this tool would be appropriate for use within adolescents. Further, interesting differences between genders were found, with girls mentioning dieting and body image, and boys mentioning their eating decisions were based on participation in sports.

The final study in this dissertation investigated the effectiveness of an Intuitive Eating (IE) program on decreasing risky eating behaviors among ninth grade high school students, specifically ON behaviors. We tested two versions of the program (single session and multisession) and looked for differences in students’ scores between each program compared to a control group who did not receive either program. Our results showed neither program had a significant impact on decreasing either behaviors associated with ON or ED symptoms, or on increasing IE. However, our results showed interesting gender differences, where boys showed fewer ON behaviors and ED symptoms than girls at the follow up test, and greater IE behaviors than girls at the pretest and posttest. Results also showed those who were more interested in the subject of nutrition tended to demonstrate more ON behaviors. This study showed nutrition education may be beneficial in decreasing risky eating behaviors, though more research is needed to determine if IE is an effective approach.