Visceral Fat-Reducing Effect of Novel Dietary Intervention Program: A Randomized Controlled Trial in Japanese Males.

Reducing visceral fat is a critical factor in preventing obesity-related health complications. In this study, we evaluated the effectiveness of our previously reported novel dietary intervention program, "Optimized Nutri-Dense Meals", designed according to the Dietary Reference Intakes (DRIs) in Japan in reducing visceral fat. This open-label, randomized controlled trial included 100 Japanese males with obesity or overweight. In total, 50 participants were assigned to a control group that continued their usual diets, and the other 50 consumed test meals twice per week for four weeks (test group). The primary outcome, visceral fat area, significantly decreased in the test group compared to that in the control group (-7.5 cm, confidence interval [CI]: -14.3 to -0.6). In addition, we measured the changes in gut flora and work productivity. The abundance of (+1.5%, CI: 0.3-2.7) and (+0.4%, CI: 0.01-0.8) increased significantly in the test group compared with those in the control group. Work Limitation Questionnaire Japanese version scores representing presenteeism also significantly increased in the test group (+1.2 points, CI: 0.2-2.3) compared with the control group. These findings suggest that dietary interventions based on Japanese DRIs can effectively decrease visceral fat and improve health outcomes over the short term without the need for a complete dietary overhaul.