Barley-Based Cereals Enhance Metabolic Health and Satiety in Overweight Korean Adults: A Randomized Trial

Background/Objectives: Recent shifts in dietary patterns have led to reduced fiber consumption, corresponding with increasing rates of obesity and metabolic disorders. Barley-based cereals with high fiber content, particularly β-glucan, may provide superior metabolic and satiety benefits compared to corn-based alternatives. This study investigated whether barley-based cereals provide superior metabolic and satiety benefits compared to corn-based alternatives in overweight Korean adults. Methods: After selecting the most optimal cereal in the phase 1 study (acute postprandial research), a 6-week randomized controlled trial (RCT) was conducted in phase 2. In the phase 2 trial, overweight adults (n = 30; mean age of 43 ± 10.89 years; 36.7% female) were randomly assigned to consume either barley (n = 15) or corn cereal (n = 15) daily for 6 weeks. Participants consumed approximately 50 g of available carbohydrates (either barley or corn cereal) in 190 mL milk. Outcome measures included anthropometric parameters, fasting blood glucose, homeostasis model assessment of insulin resistance (HOMA-IR), postprandial glucose, subjective satiety, and gut health. Results: After 6 weeks, between-group comparisons revealed significant differences favoring the barley group in body weight (barley: -0.33 kg vs. corn: +0.85 kg; difference: -1.18 kg, p = 0.027), BMI (barley: -0.14 kg/m² vs. corn: +0.03 kg/m²; difference: -0.17 kg/m², p = 0.014), and glycated albumin (barley: -0.78% vs. corn: +0.09%; difference: -0.87%, p = 0.032). Within-group analyses showed that the barley group exhibited significant reductions in percent body fat (-1.03%, p = 0.004), waist circumference (-3.64 cm, p = 0.003), waist-to-hip ratio (-0.02, p = 0.012), glycated albumin (-0.78%, p = 0.029), and LDL cholesterol (-10.57 mg/dL, p = 0.033). Conversely, the corn group showed significant increases in body weight (+0.85 kg, p = 0.026) and percent body fat (+0.84%, p = 0.020), with a significant decrease in HDL cholesterol (-2.84 mg/dL, p = 0.020). Conclusions: Barley-based cereals offer significant metabolic and satiety benefits for overweight adults compared to corn-based alternatives. These findings suggest that barley-based cereals may be an effective dietary intervention for managing obesity and metabolic disorders.