THE BODY MASS INDEX (BMI) of Japanese patients with type 2 diabetes mellitus (T2DM) has been progressively increasing, with recent reports indicating that the current average BMI is now 25.0 kg/m 2 [1]. Although the average BMI of Asian patients with T2DM is apparently low, these patients characteristically tend to possess a large amount of visceral adipose tissue (VAT) [2], presumably leading to the increase of metabolic complications associated with their T2DM.Sodium-glucose co-transporter 2 (SGLT2) inhibitors improve glycaemia and reduce body weight in patients with T2DM by enhancing urinary glucose excre- Abstract. To investigate if ipragliflozin, a novel sodium-glucose co-transporter 2 inhibitor, alters body composition and to identify variables associated with reductions in visceral adipose tissue in Japanese patients with type 2 diabetes mellitus. This prospective observational study enrolled Japanese participants with type 2 diabetes mellitus. Subjects were administered ipragliflozin (50 mg/day) once daily for 16 weeks. Body composition, visceral adipose tissue volume and plasma variables were measured at 0, 8, and 16-weeks. The subjects' lifestyle habits including diet and exercise were evaluated at baseline and 16 weeks. The primary endpoint was defined as the decrease of visceral adipose tissue mass. Twenty-four of 26 enrolled participants completed the study. The visceral adipose tissue decreased significantly (110 ± 33 to 101 ± 36 cm 2 , p = 0.005) as well as other parameters for metabolic insufficiency including hemoglobin A1c. Seventyone % of the total body weight reduction (-2.49 kg) was estimated by a decrease in fat mass (-1.77 kg), and the remaining reduction (22%) by water volume (-0.55 kg). A minor but significant reduction in the skeletal muscle index was also observed. Correlation analyses were performed to identify variables associated with changes in visceral adipose tissue and the only significant variable identified was diet therapy (Spearman's r = -0.416, p = 0.043). Ipragliflozin significantly decreased visceral adipose tissue, and improved parametres for metabolic dysfunction. Adequate diet therapy would be necessary to induce and enhance the therapeutic merit.Key words: Diet therapy, Ipragliflozin, Visceral adipose tissue tion [3][4][5]. These characteristics are suitable for treatment strategy for obese patients. While the SGLT2-associated weight loss is mainly caused by a reduction of fat mass, reduced lean muscle mass due to an increase in compensatory gluconeogenesis has been assumed in response to increased glucose excretion. Accordingly, sarcopenia related with SGLT2 inhibitor administration has been one of the major concerns in daily clinical practice [6][7][8], as well as compensatory hyperphagia associated with increased glucose excretion [9][10][11].Given the significantly lower average BMI of Asian patients with T2DM as compared to that found in Western populations, it is important to evaluate potential changes in body composition (VAT and lean mass) associated with SGL...