The Association Between Dietary Changes to Lose Weight and Mental Health Status in the National Health and Nutrition Examination Survey, 2005-2006

Background Weight loss is a common endeavor taken by millions of residents annually in the U.S.—a country with a 31% overweight and 42% obesity rate. Weight loss is associated with numerous physical health benefits, such as better cardiovascular health. However, unhealthy weight loss strategies can cause adverse mental health effects. Past research has focused on how weight loss strategies affect the mental health of a general population—rather than those who are trying to lose weight—or has investigated a diverse array of weight loss strategies. This paper explores how dietary changes for weight loss are associated with mental health, specifically through several variables used in the Patient Health Questionnaire-9 (PHQ9), which measures depression severity. We hypothesize that eating less and skipping meals will be associated with poorer mental health status, while eating fewer carbohydrates, eating less fat, and drinking more water will be associated with better mental health status. Methods and Findings This study uses the U.S. 2005-2006 National Health and Nutrition Examination Survey (NHANES) 2005. Univariate (descriptive statistics), bivariate (correlation coefficient), and multivariate (ordinal logistic regression) analyses were performed. The main results show that ‘skipped meals’ was positively associated with ‘feeling bad about yourself,’ ‘feeling down, depressed, or hopeless,’ and ‘little interest in doing things.’ ‘Ate fewer carbohydrates’ was negatively associated with the ‘little interest in doing things.’ Conclusion Differing dietary changes used for weight loss, particularly skipping meals and eating fewer carbohydrates, are associated with differences in mental health status. Health care professionals providing weight loss guidance should be cognizant of patients’ baseline mental health and the potential for changes in mental health with different dietary strategies. Future research employing a longitudinal approach to determine whether there is evidence of a causal relationship between these and other dietary strategies and subsequent mental health outcomes.