Food preferences and weight change during low-fat and low-carbohydrate diets.

UNLABELLED: Understanding associations between food preferences and weight loss during various effective diets could inform efforts to personalize dietary recommendations and provide insight into weight loss mechanisms. We conducted a secondary analysis of data from a clinical trial in which participants were randomized to either a 'choice' arm, in which they were allowed to select between a low-fat diet (n = 44) or low-carbohydrate diet (n = 61), or to a 'no choice' arm, in which they were randomly assigned to a low-fat diet (n = 49) or low-carbohydrate diet (n = 53). All participants were provided 48 weeks of lifestyle counseling. Food preferences were measured at baseline and every 12 weeks thereafter with the Geiselman Food Preference Questionnaire. Participants were 73% male and 51% African American, with a mean age of 55. Baseline food preferences, including congruency of food preferences with diet, were not associated with weight outcomes. In the low-fat diet group, no associations were found between changes in food preferences and weight over time. In the low-carbohydrate diet group, increased preference for low-carbohydrate diet congruent foods from baseline to 12 weeks was associated with weight loss from 12 to 24 weeks. Additionally, weight loss from baseline to 12 weeks was associated with increased preference for low-carbohydrate diet congruent foods from 12 to 24 weeks. Results suggest that basing selection of low-carbohydrate diet or low-fat diet on food preferences is unlikely to influence weight loss. Congruency of food preferences and weight loss may influence each other early during a low-carbohydrate diet but not low-fat diet, possibly due to different features of these diets. CLINICAL TRIAL REGISTRY: NCT01152359.

Obesity and Overweight among Black American Adolescent Females: The Role of Social Influences in Everyday Dietary Practices

Obesity and overweight disproportionately impact Black American adolescent females—placing them at a lifetime of elevated physical health risks. Despite this burden, the literature that explores the contributors to obesity and overweight among Black American adolescent females remains limited and unclear. This dissertation aims to develop knowledge related to obesity and overweight in Black American adolescent females, by appraising the current understanding of factors that contribute to their obesity and overweight, and explicating the everyday social influences on dietary practices. The primary study conducted for this dissertation used a mixed method, multiple case study design to examine the mother, daughter, and other household contributors to Black American adolescent daughters’ everyday practices of food consumption, acquisition, preparation, and planning. Findings reveal the importance of understanding the complex and dynamic ways mothers and other household members contribute to a holistic view of everyday dietary practices among adolescent daughters. By deeply examining the nuanced ways the multiple cases varied, context-dependent knowledge essential to understanding the complicated health challenge of obesity was produced. Subsequently, recommendations are provided for health providers and scholars to more holistically approach and examine obesity—particularly among populations who are disproportionately affected.