Effects of Very Low-Calorie Diet versus Roux-en-Y Gastric Bypass Surgery on Body Composition in Patients with Obesity.

Roux-en-Y gastric bypass (RYGB) is the most effective treatment for severe obesity. A very low-calorie diet (VLCD) is another effective dietary intervention to treat obesity. This study evaluated the effect of a VLCD versus RYGB on weight reduction, changes in body composition and the resolution of comorbidities during a 12-week period. Individuals with obesity at the obesity clinic, Ramathibodi Hospital, Mahidol University, Thailand with a body mass index (BMI) ≥ 37.5 kg/m2 or ≥32.5 kg/m2 with obesity-related complications were recruited. Treatment options, either RYGB or VLCD, were assigned depending on patients' preferences and physicians' judgment. The analysis included 16 participants in the RYGB group and 15 participants in the VLCD group. Baseline characteristics were similar between groups; nevertheless, the participants in the VLCD group were significantly younger than those in the RYGB group. The number of patients with type 2 diabetes (T2D) was slightly higher in the RYGB group (43.8% vs. 33.3%, p = 0.552). Additionally, patients in the RYGB group had a longer duration of T2D and were treated with anti-diabetic agents, while VLCD patients received only lifestyle modifications. At 12 weeks, total and percentage weight loss in the RYGB and VLCD groups, respectively, were as follows: -17.6 ± 6.0 kg vs. -15.6 ± 5.1 kg (p = 0.335) and -16.2% ± 4.3% vs. -14.1% ± 3.6% (p = 0.147). Changes in biochemical data and the resolution of comorbidities were similar between the groups at 12 weeks. A 12-week VLCD resulted in similar weight loss and metabolic improvement compared with RYGB. Large-scale studies with long follow-up periods are needed to elucidate whether VLCD is a viable alternative treatment to bariatric surgery.

Correlation between magnetic resonance imaging proton density fat fraction (MRI-PDFF) and liver biopsy to assess hepatic steatosis in obesity.

Obesity is highly associated with Non-alcoholic fatty liver disease (NAFLD) and increased risk of liver cirrhosis and liver cancer-related death. We determined the diagnostic performance of the complex-based chemical shift technique MRI-PDFF for quantifying liver fat and its correlation with histopathologic findings in an obese population within 24 h before bariatric surgery. This was a prospective, cross-sectional, Institutional Review Board-approved study of PDFF-MRI of the liver and MRI-DIXON image volume before bariatric surgery. Liver tissues were obtained during bariatric surgery. The prevalence of NAFLD in the investigated cohort was as high as 94%. Histologic hepatic steatosis grades 0, 1, 2, and 3 were observed in 3 (6%), 25 (50%), 14 (28%), and 8 (16%) of 50 obese patients, respectively. The mean percentages of MRI-PDFF from the anterior and posterior right hepatic lobe and left lobe vs. isolate left hepatic lobe were 15.6% (standard deviation [SD], 9.28%) vs. 16.29% (SD, 9.25%). There was a strong correlation between the percentage of steatotic hepatocytes and MRI-PDFF in the left hepatic lobe (r = 0.82, p < 0.001) and the mean value (r = 0.78, p < 0.001). There was a strong correlation between MRI-derived subcutaneous adipose tissue volume and total body fat mass by dual-energy X-ray absorptiometry, especially at the L2-3 and L4 level (r = 0.85, p < 0.001). MRI-PDFF showed good performance in assessing hepatic steatosis and was an excellent noninvasive technique for monitoring hepatic steatosis in an obese population.