Establishing a proof of concept for the effects of low-carbohydrate, high-fat diet (LCHFD) and physical activity on body composition in type 2 diabetes.

Overweight and obesity are both a risk factor for developing and exacerbating type 2 diabetes (T2D). While the most common diet used to treat overweight and obesity focus on high-carbohydrate, low-fat, energy deficit diets, recently, low-carbohydrate, high-fat diets (LCHFD) have become popular in targeting obesity. This proof-of-concept study attempted to determine if an LCHFD could improve body composition variables, or if a concurrent treatment of LCHFD and physical activity would create an interference effect in individuals with T2D. Overweight and obese with T2D (n = 39) were assigned into either a 16-week combined physical activity and LCHFD group (ConG), LCHFD-only group (DieG) or control group (NonG). No statistically significant (p > 0.01) changes were found in body mass in the ConG (2.0%, F = 0.039, P = 0.846) and DieG (2.5%, F = 0.188, P = 0.669); for body mass index in the ConG (2.2%, F = 0.046, P = 0.832) and DieG (2.3%, F = 0.098, P = 0.758.); and waist-to-hip ratio in the ConG (0%, F = 0.002, P = 0.968) and DieG (0%, F = 0.023, P = 0.882). However, clinically significant changes were observed in HbA1c in the ConG male group (23% decrease); percentage body fat for the ConG (16.7%, F = 1.682, P = 0.208, g = 0.534) and DieG (13.0%, F = 0.638, P = 0435, g = 0.361); for waist circumferences in the ConG (5.4%, F = 0.686, P = 0.416, g = 0.341) and DieG (6.3%, F = 1.327, P = 0.264, g = 0.520); and for hip circumference in the ConG (5.8%, F = 0.993, P = 0.329, g = 0.410) and DieG (7.0%, F = 2.668, P = 0.119, g = 0.737). Results indicate that moderate clinically significant changes in body composition are achievable with LCHFD and/or daily walking in obese adults living with T2D. However, more robust research is required to determine the effects of LCHFD, with or without concurrent physical activity, on obesity and other diabetic complication markers.