LAUSR

The increasing demand for the surgical treatment of obesity is in line with the increasing prevalence of obesity worldwide, particularly class III obesity. Nobody will challenge today the well-known beneficial effect of bariatric surgery in obesity treatment, notably the main effect on weight loss and weight-related co-morbidities. Incidentally, these positive effects are not due to the surgery per se but to the weight loss achieved (1), including type 2 diabetic patients who present with obesity (2). There are, in parallel, wellknown risk of complications as well as risk related to the voluntary malabsorption procedure which have been described decades ago. The latter progressively leads to a deficit in both macronutrients (protein in borderline supply) as well micronutrients (vitamins, minerals, and trace elements). The degree of deficit of nutrients and the degree of potential nutrient imbalance can vary enormously among patients. The inter-individual variability appears to range from 20 to 100% (3). The nature of surgery intervention as well as endogenous individual factors undoubtedly plays a role. The topics of the present Frontiers in Endocrinology issue gather various contributions highlighting the actual research activities in bariatric surgery. On the first sight, this may appear rather heterogeneous. In order to demonstrate the complementarity of these various bariatric surgery topics, their articulation is depicted in a synthetic global scheme (Figure 1), which attempts to show the interrelated field of the research domain presented. As shown in Figure 1, the different topics can be tentatively classified into several headlines which shall be discussed below.