The eating-related behaviours, expectations, and experiences of individuals before and after undergoing bariatric surgery

Abstract

While a variety of disordered eating behaviours can play significant roles in the development and maintenance of obesity, little is known about their prevalence and implications in individuals who undergo bariatric (weight loss) surgery. Patients’ expectations and experiences of eating behaviour change after surgery, and their reasons for undergoing one particular bariatric procedure rather than another, are also not well-understood. This thesis investigated these topics in two reviews and an original research study, with the results presented in four papers. Paper 1 reviewed the literature on eating-related behaviours, disorders, and expectations in pre-bariatric surgery candidates. A variety of disordered eating behaviours appear more common in bariatric candidates than in non-obese populations, with evidence that 4-45% of candidates have binge eating disorder (BED), 20-60% graze, 2-42% have night eating syndrome (NES), 38-59% emotionally eat, and 17-54% fit the criteria for food addiction. Expectations are high, with candidates believing their procedure will almost guarantee significantly improved eating behaviours. Paper 2 systematically reviewed the literature on pre- to post-surgery changes in eating disorders and disordered eating behaviours after Roux-en-Y gastric bypass (RYGB), adjustable gastric banding (AGB), or vertical sleeve gastrectomy (VSG). Short- to medium-term reductions in BED and related behaviours were common after RYGB. Short- to medium-term reductions in emotional eating and short to long-term reductions in bulimic symptoms were reported after RYGB. Reoccurrences and new occurrences of disordered eating, especially BED and binge episodes, were apparent after RYGB and AGB. Limited and low-quality evidence hindered conclusions and comparisons. The literature was unclear on whether any bariatric procedure leads to long-term improvement in disordered eating. Using content analysis and quantitative analyses, paper 3 examined patients’ reasons for undergoing their particular bariatric procedure rather than another procedure. RYGB was most often chosen because of its evidence base and success rate, VSG due to a medical practitioner’s recommendation, preference, or choice, and AGB because of characteristics of the procedure including its reversibility. A desire to avoid post-surgical complications and risks such as leaks or malabsorption was the most commonly cited reason against both RYGB and VSG, while information and evidence from failure rates and others’ unsuccessful experiences was most common against AGB. In Paper 4, content analysis and quantitative analyses were utilised to investigate patients’ expectations and experiences of eating-related behaviour change after bariatric procedures. The most common pre-surgical expectations were of eating less and feeling increased satiety (47.0%) and reduced hunger (30.4%). After surgery, patients more often reported positive (84.9%; most often eating less) than negative eating-related experiences (43.7%; most often continued or new problematic/disordered eating behaviours). Disordered eating behaviours persisted or emerged in 17.1% and improved or resolved in 18.1%. Negative experiences were more frequently reported at ≥ 18 months than ≤ 1 year. Reporting any negative eating-related experience was related to poorer outcomes after VSG and AGB, but not RYGB. Relationships between negative eating-related experiences and poorer outcomes, and positive experiences and improved outcomes, were significant almost exclusively from ≥ 18 months post-surgery. The findings of this thesis show that the prevalence and consequences of disordered eating behaviours, eating disorders, and negative eating-related experiences are substantial for pre- and post-surgical bariatric patients. These issues are not always cured or even improved by bariatric surgery, and can continue, worsen, or begin de novo after surgery. Eating-related difficulties may be especially likely to begin or re-emerge at one to two years post-surgery. Patients are likely to benefit from the incorporation of eating-related education, assessment, and provision of therapeutic strategies by bariatric practices from prior to surgery to well beyond two years post-surgery. It is also recommended that surgeons be aware of the different reasons why patients undergo one bariatric procedure rather than another, and ensure that patients receive accurate, unbiased, and individualised information regarding the different procedures.