Aim A very‐low‐calorie diet (VLCD) can reverse the underlying defects of type 2 diabetes mellitus (DM) in obese subjects. We determined the efficacy, safety, and durability of VLCD in Thai patients with DM and obesity. Methods Twenty Thai patients with DM and obesity were enrolled. After a 2‐week trial, VLCD (600 kcal/day) was continued for 8 weeks, followed by a 4‐week transition period. Data on diabetes remission (fasting plasma glucose level <126 mg/dl and HbA 1c <6.5% without the use of glucose‐lowering medications), glycemic control, metabolic parameters, and quality of life (QOL) were collected along with indices of insulin resistance (IR) and beta cell function. Glycemic control 12 months after discontinuation of VLCD was also examined. Results Among 19 patients (age 48 ± 2 years, BMI 27.7 kg/m 2 ) who completed the study, rapid improvement in glycemic control was observed in the first 2 weeks of VLCD. At both 8 and 12 weeks, diabetes remission was achieved in 79%. Significant weight loss was accompanied by a significant reduction in IR and an increase in beta cell function, starting at 4 weeks of VLCD. QOL also significantly increased. At 12 months after VLCD, however, DM remission was achieved in approximately 30%. Conclusion Very‐low‐calorie diet was effective and safe in inducing short‐term diabetes remission in Thai subjects by ameliorating beta cell function and IR. Optimal long‐term glycemic control was potentially durable as one‐third of subjects remained without diabetes medication 12 months after VLCD.

Background: The aim of the present study was to evaluate the efficacy of Roux-en-Y gastric bypass (RYGB) vs. sleeve gastrectomy (SG) on glycemic control and blood lipid profile at preoperative (baseline), three and six months after surgery. Methods: In a prospective non-randomized design, 32 participants, SG (n = 11) and RYGB (n = 21) completed the study. Results: Results showed that fasting blood glucose (FBG) and Hemoglobin A1C (HbA1C) were significantly reduced from 113.55±30.18 mg/dL at baseline to 93.6±14.81 mg/dL at three months post operation following SG (p = 0.006). In addition, HbA1C decreased significantly in both groups at baseline, three- and six-months post operation (SG 6.41± 0.96, 5.4±0.36 and 5.28±0.57 % (p = 0.022) and RYGB 5.91± 0.94, 5.11± 0.57 and 4.96± 0.55% (p<0.001) respectively). Levels of high-density lipoprotein (HDL) were restored significantly in both groups at 6 months compared to three months post-surgery (SG 41.2± 9.99, 38.67±4.85 and 45.36± 6.22 (p = 0.023) and RYGB 42.67± 9.97, 36.58± 6.06 and 43.03± 6.66 (p =0.003) respectively), whereas there is no significant different in low-density lipoprotein and total cholesterol. Conclusions: Both bariatric surgery (SG and RYGB) improved glycemic control and blood lipid profile. Trial registration: The trial is registered with Thai Clinical Trials Registry (TCTR20210429004) April 29, 2021.