Background: The contemporary Western food environment has been implicated as a key driver of obesity and disorders of overeating, which have now reached pandemic status. This has been matched with burgeoning interest in the novel concept of food addiction (FA) and in bariatric weight loss surgeries, currently the most effective treatment for obesity. Patients who choose surgery typically exhibit relatively higher levels of obesity and maladaptive eating, struggle to control their intake of (hyper)palatable/refined foods, and have high rates of psychopathology and related health problems. Perplexingly, however, the reported rates of FA in the bariatric are relatively low or variable. Additionally, weight loss and other benefits of bariatric surgeries, although well-established, vary according to both the type of surgery and individual biopsychosocial factors. Consequently, there is a critical need for prospective research aimed at investigating interactions between these factors. Aim and Objectives: The research investigated the usefulness of the novel concept of FA in the bariatric weight loss surgery domain, with the aim of improving predictive capacity of postsurgical outcomes to ensure better patient to surgery fit and more adaptive postsurgical adjustment, including, and guiding patient education and pre and postsurgical care. Research Format: The study began with a comprehensive review of literature related to societal increases in obesity, homeostatic and hedonic mechanisms of appetite and satiety, and the novel construct of FA, together with an overview of bariatric surgery research, followed by two prospective empirical studies completed as elements of this research. Study 1 investigated the applicability and performance of Yale Food Addiction Scale (YFAS)-scored FA in a sample of presurgery candidates. Study 2 investigated outcomes of bariatric surgery over time and whether potential interactive effects between presurgical FA and type of surgery resulted in different biopsychosocial outcomes. Design: A prospective mixed design was employed to investigate presurgical characteristics and postsurgical outcomes on a range of relevant biopsychosocial variables, with individuals completing self-report questionnaires at pre and postsurgery psychological screening sessions at a university-affiliated weight management centre in the United States and a major metropolitan hospital in Australia. Study I Methods and Findings: Study 1 investigated prevalence of FA and applicability of conventionally used metrics for 166 presurgery candidates. Self-report measures assessed FA (YFAS), body mass index (BMI), disordered eating, addictive personality, psychopathology, and diet. Data were analysed using Statistical Package for Social Sciences (SPSS) version 20 via a series of between-groups analyses performed on presurgery data only. Results indicated a need for further research to establish the utility of FA and the applicability of YFAS in its existing form to the bariatric surgery domain. Study 2 Methods and Findings: Study 2 investigated main effect outcomes of bariatric surgery and mixed interaction effects for 193 weight loss surgery patients. A total of 70 participants were lost to attrition, with 123 three-month completers and 69 twelve-month completers. Between-subjects independent variables (IVs) were “pre-surgical food addiction” on two levels, those with (FA) or without (NFA); and “type of surgery” on two levels, sleeve gastrectomy (SG) versus bypass. The IV “time” varied on three levels, presurgery, 3 months postsurgery, and 12 months postsurgery. The same range of biopsychosocial dependent variables (DVs), as described in Study 1, was investigated. Data were analysed using SPSS version 20. Results indicated an overall beneficial effect of surgery for reducing body weight and improving quality of life, mood, and eating behaviour. There was partial support for the hypothesis that inferior outcomes in depression and alcohol use would be observed for those with presurgical FA who underwent SG. Although an addiction transfer effect was anticipated and observed, it was an unexpected finding that was specific to SG. Conclusions: The research offers support for the applicability of the FA construct in bariatric settings. Although bariatric weight loss surgeries were effective overall, interaction effects offer support for the concept that those with presurgical FA are at relatively increased risk of worse depression and eating related outcomes as well as increased alcohol intake following SG, compared to bypass surgeries. More research is required to investigate specific bariatric surgery-related factors and how they relate to the construct of FA. This would include further development of YFAS, investigation of cross-cultural differences, increased attention to eating behaviours, and their association with postsurgical complications and investigation of other substance or behavioural addictions.