Obesity is a disease worldwide. Hence, many patients seek many different treatments for obesity. The methods for obesity include medical and surgical treatment. The medicine treatment indication for diabetes previously increased indication to weight loss for obese patients now. Recently, the four approved weight loss medicines by the Taiwan Food and Drug Administration (TFDA) include Orlistat, Liraglutide, Contrave, and Semaglutide. In addition to medications for weight loss, indications for more than 30 body mass index (BMI) and more than 27 BMI with uncontrol obesity-related comorbidities.

Another weight loss treatment was bariatric surgery. The surgical treatment focuses on morbidity obese patients. Decrease food intake and absorb calories by changing the structure of the stomach and intestine to weight loss and improve comorbidities. Moreover, three functions for bariatric surgery by different mechanisms to weight loss outcome, include (1) restriction, (2) malabsorption, (3) mixed function, and which indication for more than 37.5 BMI and more than 32.5 BMI with two or more uncontrol obesity-related comorbidities.

Since obesity is not a condition that can be cured by surgical removal of lesions forever, patients often experience weight loss failure after receiving both medical and surgical treatments. Particularly, the probability of weight loss failure after medical treatment is higher than that after surgical treatment. Complexed risk factors caused failure weight loss from behavioral dietary, quality of life, remission rate of comorbidities, genetic inheritance, physical Inactivity, and psychological status. Moreover, failure weight loss has two definitions (1) weight regain (WR) and (2) insufficient weight loss (IWL). The investigators searched many studies to organize failure weight loss definitions referenced by Surgery for Obesity and Related Disease (SORD) in the American Society for Metabolic and Bariatric Surgery (ASMBS). IWL is defined as less than 50 percent excess weight loss (%EWL) or less than 35 BMI after 18 months. WR is defined as (1) more than the nadir weight of 10 kg (2) more than the nadir weight of 25% EWL (3) more than the nadir weight of 5 BMI (4) successfully reduced to a BMI below 35, but after 1-year post-treatment, it exceeded BMI 35 (5) at any point within 1-year post-treatment, the weight is higher than the lowest weight achieved. (6) the weight regained is more than 15% of the lowest weight achieved. In contrast to weight gain after medicine which is defined by population proportion 5%, 10%, 15%, 20% statistical analysis.

The study was an observational cohort study. The investigators will use the six types of questionnaires (1) Demographic parameters and exercise frequency (2) WHOQOL-BREF scale (3) Bariatric Quality of Life Questionnaire (BQL) (4) Three-Factor Eating Questionnaire (TFEQ-R18) (5) Yale Food Addiction Scale (YFAS)2.0 (6) Depression Anxiety Stress Scales-21 (DASS-21). The investigators hypothesize that the above risk factors are significantly related to each other and failure to weight loss after bariatric surgery. The aims are to analyze the risk rate of weight regain by different weight loss treatments that can promote quality of weight management.