REVIEW Weight Recidivism Post-Bariatric Surgery: A Systematic Review Shahzeer Karmali & Balpreet Brar & Xinzhe Shi & Arya M. Sharma & Christopher de Gara & Daniel W. Birch Published online: 1 September 2013 # Springer Science+Business Media New York 2013 Abstract Obesity is considered a worldwide health problem of epidemic proportions. Bariatric surgery remains the most effective treatment for patients with severe obesity, resulting in improved obesity-related co-morbidities and increased overall life expectancy. However, weight recidivism has been observed in a subset of patients post-bariatric surgery. Weight recidivism has significant medical, societal and economic ramifications. Unfortunately, there is a very limited under- standing of how to predict which bariatric surgical patients are more likely to regain weight following surgery and how to appropriately treat patients who have regained weight. The objective of this paper is to systematically review the existing literature to assess the incidence and causative factors associ- ated with weight regain following bariatric surgery. An elec- tronic literature search was performed of the Medline, Embase and Cochrane library databases along with the PubMed US national library from January 1950 to December 2012 to identify relevant articles. Following an initial screen of 2,204 titles, 1,437 abstracts were reviewed and 1,421 met exclusion criteria. Sixteen studies were included in this analysis: seven case series, five surveys and four non-randomized controlled trials, with a total of 4,864 patients for analysis. Weight regain in these patients appeared to be multi-factorial and overlapping. Aetiologies were categorized as patient specific (psychiatric, physical inactivity, endocrinopathies/metabolic and dietary non-compliance) and operation specific. Weight regain following bariatric surgery varies according to duration of follow-up and the bariatric surgical procedure performed. The underlying causes leading to weight regain are multi- factorial and related to patient- and procedure-specific factors. Addressing post-surgical weight regain requires a systematic approach to patient assessment focusing on contributory die- tary, psychologic, medical and surgical factors. Keywords Post-bariatric surgery . Obesity . Weight recidivism Introduction Currently, more than 20 % of the world's population is over- weight, and approximately 10 % are obese [1]. Severe obesity (BMI of over 35 kg/m 2 ) is associated with an increased incidence of chronic diseases including hypertension, type 2 diabetes mellitus, coronary artery disease, stroke and dyslipidaemia [1]. Furthermore, each five-point increase in BMI over 25 kg/m 2 is associated with a 30 % increase in all-cause mortality [2]. A number of meta-analyses have demonstrated the effec- tiveness of bariatric surgery in improving severe obesity and its associated co-morbidities [3–6]. As a result, it is not sur- prising that the number of bariatric surgeries performed has risen over 14-fold in the last 2 years [1]. Despite marked weight loss following bariatric surgery, long-term weight regain and failure of sustained weight loss is seen in a proportion of patients [7, 8]. Weight regain may occur with all three of the most commonly performed bariatric surgeries [Roux-en-Y gastric bypass (RYGB), adjustable gas- tric banding (AGB) and vertical sleeve gastrectomy (VSG)] [9]. Sugerman [8] reported that the magnitude of excess weight loss in gastric bypass patients diminishes over time with the percentage of excess body weight loss (EBWL) decreasing from 66 % at 1–2 years to 50 % at 10 years. It is estimated that approximately 10–20 % of patients regain a significant portion of their lost weight with long-term follow-up [7]. This weight S. Karmali (*) : B. Brar : X. Shi : A. M. Sharma : C. de Gara : D. W. Birch Center for the Advancement of Minimally Invasive Surgery (CAMIS), Royal Alexandra Hospital, Room 405 CSC, 10240 Kingsway Ave, Edmonton, AB T5H 3 V9, Canada e-mail: shahzeer@ualberta.ca OBES SURG (2013) 23:1922–1933 DOI 10.1007/s11695-013-1070-4