Article Special diets in modern America: Analysis of the 2012 National Health Interview Survey data Brenda Leung 1 , Romy Lauche 2 , Matthew Leach 3 , Yan Zhang 4 , Holger Cramer 5 and David Sibbritt 2 Abstract Background: Special diets are frequently used by the public but reasons for use and characteristics of users remain unclear. Aim: To determine prevalence of the use of special diets, the individual characteristics associated with their use and reasons for use. Methods: The secondary analysis used data from the 2012 National Health Interview Survey (NHIS), a cross-sectional household interview survey of a nationally representative sample of non-hospitalized US adult popu- lations (n ¼ 34,525). The dependent variables in this secondary analysis were the use of a special diet (vegetarian, macrobiotic, Atkins, Pritikin, and Ornish) ever and during the past 12 months. Independent variables included socio- demographic, clinical and behavioral variables. Prevalence of special diet use and reasons for use were analyzed descriptively. Associations between independent and dependent variables were analyzed using Chi-square tests and logistic regression. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Results: Lifetime and 12-month prevalence of using special diets were 7.5% (weighted n ¼ 17.7 million) and 2.9% (weighted n ¼ 6.9 million), respectively. Individuals using special diets in the past 12 months were more likely female (OR ¼ 1.45; 95% CI ¼ 1.21– 1.74), not married (OR ¼ 0.76; 95% CI ¼ 0.63–0.91), college-educated (OR ¼ 1.98; 95% CI ¼ 1.25–3.11) and depressed (OR ¼ 1.50; 95% CI ¼ 1.14–1.98). They more likely also used herbal products (OR ¼ 2.35; 95%CI ¼ 1.84–2.99), non- vitamin (OR ¼ 1.82; 95% CI ¼ 1.45–2.27) and vitamin supplements (OR ¼ 1.57; 95% CI ¼ 1.24–1.99). Diets were mainly used to improve overall health (76.7%) or for general wellness/prevention (70.4%). Conclusions: Special diets are mainly used for unspecific health reasons by those who are females, have a college degree or with depression, and commonly used in conjunction with herbs and dietary supplements. Keywords Diet, survey, prevalence, population characteristics Introduction Diets focusing on the consumption or avoidance of specific food groups or types of foods have been in existence for centuries, and continue to gain popularity in the modern world (Foxcroft, 2011). The factors that influence a person’s decision to commence a spe- cial diet are many and varied. For some people, there may be clinical indications to initiate such a diet, such as overweight/obesity (e.g. Atkins, Zone, and Weight Watchers diets for weight loss) or the presence of modifiable disease risk factors (e.g. Dietary Approach to Stop Hypertension (DASH) diet to mitigate the risk of cardiovascular disease). Cultural, religious and socio- ethical reasons can also be important enablers of special diets (e.g. vegetarian or vegan diets), as can a desire to improve general health and wellbeing (e.g. detoxification diets) (Vainio et al., 2016). Data from the US National Health Interview Survey (NHIS) reveal a stable use of special diets over the 2002– 2012 period, with approximately 3% of American adults reporting the use of one or more special diets (i.e. vegetarian 1 Faculty of Health Sciences, University of Lethbridge, Canada 2 Australian Research Centre in Complementary and Integrative Medicine (ARCCIM), University of Technology Sydney, Australia 3 Department of Rural Health, University of South Australia, Australia 4 Department of Family and Community Medicine, Texas Tech University Health Sciences Center, USA 5 Department of Internal and Integrative Medicine, University of Duisburg- Essen, Germany Corresponding author: Brenda Leung, Faculty of Health Sciences, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta T1K 3M4, Canada. Email: Brenda.leung@uleth.ca Nutrition and Health 2018, Vol. 24(1) 11–18 ª The Author(s) 2017 Reprints and permission: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0260106017732719 journals.sagepub.com/home/nah