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Abstract
Food insecurity is defined as a lack of access to sufficient and nutritious food to meet one’s basic needs. Individuals in food-insecure households often consume a Western diet (high-fat and high-sugar foods) and experience unpredictable food access. Given the fact that 17.3% of households with children under 18 years of age experienced food insecurity in 2022, there is an urge to investigate the potential adverse effects of food insecurity during development later in life. Although current literature suggests the coexistence of food insecurity and obesity in both children and adults, the underlying mechanisms that drive this paradoxical association remain unclear due to the various constraints involved in human studies. Recently, several researchers have developed food insecurity models employing animals. However, there are some critical differences among these food insecurity models, such as different animal species (Aves vs. mammals), strain of rodents, age, sex, and severity, length of food insecurity. Thus, this dissertation aims to first establish a novel adolescent food insecurity model in rodents and then investigate the effects of unpredictable food access along with a Western diet during the development on eating behavior and susceptibility to diet-induced obesity in adulthood. I hypothesized that adolescent food insecurity alters eating behavior and increases susceptibility to diet-induced obesity in adulthood. Juvenile Wister rats, both males and females, were exposed to the adolescent food insecurity model for five weeks until they entered adulthood. Food-insecure rats had sufficient amounts of food but received it unpredictably during this paradigm. Various behavioral testing and obesogenic diet challenges during adulthood with ad libitum food access were conducted in females (Chapter 3), as well as body composition and energy expenditure analyses were performed in males (Chapter 4). Overall, female rodents with a history of unpredictable food access exhibited greater fat mass and liver lipid droplets when challenged with an obesogenic diet in adulthood. In contrast, adolescent food insecurity did not impact male rodents similarly. Collectively, these findings suggest that adolescent food insecurity may have sex-specific long-term consequences for metabolism later in life.