Effect of meal patterns on weight loss after Sleeve Gastrectomy in patients undergoing surgery at Padova University Hospital.

Introduction: Nowadays, obesity and being overweight are a major global concern. The choice of obesity treatment varies according to the individual and the cause of obesity. Among these, bariatric surgery is a well-known and effective treatment option for obesity treatment. As obesity is a multi-caused disease, in its treatment also, different methods are usually used together and affect each other. As a result, studying in the field of understanding these interactions can also be very useful. Goal and scope: Evaluation the effect of meal patterns of patients undergoing bariatric surgery on weight loss after surgery. The results of this study can be useful in more accurate prediction of the results of bariatric surgery and giving a better perspective of the result of weight loss after surgery based on the patient's meal pattern. Material and method: In this observational study, 124 obese patients underwent bariatric surgery of Sleeve gastrectomy from 2019 to 2021 at Padua University Hospital and were followed up with available data up to 1 year after surgery. All evaluations before and after surgery have been done and patients were clustered in 5 different clusters (cluster I: consumption of three main meals of breakfast, lunch and dinner, cluster II: varied meal patterns and not following a particular pattern, cluster III: eating three main meals of breakfast, lunch and dinner and two snacks in the morning and evening, cluster IV: overeating during the day hours and cluster V overeating during the day and night hours) data have been recorded in the electronic data system of Padova hospital (E-health). Then descriptive statistics parameters were calculated for all variables (numerical and nominal) using the SPSS statistics program version 24.0. Results were expressed as the mean ± standard deviation or percentage of total. Results: After Sleeve gastrectomy, our 124 patients, all of whom were severely obese and also had obesity-related comorbidities, experienced favorable weight loss so that the mean body weight in all study population from 119.8± 22.58 kg pre-operation body weight decreased to 82.2±18.65 kg (p-value <0.00001) one year after surgery (31% weight loss). Regarding the meal pattern, although the results of weight loss were approximately close to each other for all meal pattern clusters, but it can be said that clusters I and III were in the best conditions of weight loss and experienced the greatest change (approximately 33% weight loss), while cluster V experienced the least amount of weight loss (27% weight loss and the maximum rate of stopping weight loss). In addition to the positive effect of bariatric surgery on weight loss in study population, the comorbidity status of patients also improved on average by 70% after surgery. Conclusion: Our study confirmed the positive effect of bariatric surgery on weight loss and improving obesity-related comorbidities. The effect of bariatric surgery on short-term weight loss is very significant and evident, but there may not any certainty in its durability in the long term. Although in our study, a decisive result of the effect of meal pattern on weight loss after surgery was not adopted, but the observations weakly supported this consequence that probably patients who are in cluster I and III will probably get a better result from bariatric surgery than people who are in cluster V. On the other hand, our study strongly confirmed that having a special wrong eating habits such as overeating at night, or it can be called night eating disorder (NES), which is a distinctive feature of Cluster V, is more relevant than other meal patterns on weight loss after bariatric surgery. Overall, examining the effect of a behavioral pattern (meal pattern) on the result of a clinical practice is not simple. So, further multidisciplinary studies needed to clarify the possible relationships between meal patterns and weight loss after bariatric surgery.