High-protein vs. standard-protein diets in overweight and obese patients with heart failure and diabetes mellitus: findings of the Pro-HEART trial

Aims: The intermediate-term effects of dietary protein on cardiometabolic risk factors in overweight and obese patients with heart failure and diabetes mellitus are unknown. We compared the effect of two calorie-restricted diets on cardiometabolic risk factors in this population. Methods and results: In this randomized controlled study, 76 overweight and obese (mean weight, 107.8 ± 20.8 kg) patients aged 57.7 ± 9.7 years, 72.4% male, were randomized to a high-protein (30% protein, 40% carbohydrates, and 30% fat) or standard-protein diet (15% protein, 55% carbohydrates, and 30% fat) for 3 months. Reductions in weight and cardiometabolic risks were evaluated at 3 months. Both diets were equally effective in reducing weight (3.6 vs. 2.9 kg) and waist circumference (1.9 vs. 1.3 cm), but the high-protein diet decreased to a greater extent glycosylated haemoglobin levels (0.7% vs. 0.1%, P = 0.002), cholesterol (16.8 vs. 0.9 mg/dL, P = 0.031), and triglyceride (25.7 vs. 5.7 mg/dL, P = 0.032), when compared with the standard-protein diet. The high-protein diet also significantly improved both systolic and diastolic blood pressure than the standard-protein diet (P < 0.001 and P = 0.040, respectively). Conclusions: Both energy-restricted diets reduced weight and visceral fat. However, the high-protein diet resulted in greater reductions in cardiometabolic risks relative to a standard-protein diet. These results suggest that a high-protein diet may be more effective in reducing cardiometabolic risk in this population, but further trials of longer duration are needed.