Caloric restriction improves glucose metabolism, body-fat composition
Reduced caloric intake results in a significant improvement in glucose metabolism and body-fat composition, including liver-fat content, according to a study. Changes in ferritin levels appear to mediate the striking reduction in liver fat.
However, in the context of caloric restriction, reduced red meat intake and increased fibre intake do not seem to confer additional beneficial impact on the improvement in cardiometabolic risk parameters.
In this prospective, randomized and controlled dietary intervention study performed over 6 months, all groups reduced their daily intake of calories by 400 kcal. The “control” group (n=40) only had this requirement. The “no red meat” group (n=48) also aimed to avoid eating red meat, and the “fibre” group (n=44) increased fibre intake to 40 g/d.
The investigators performed anthropometric parameters and frequently sampled oral glucose tolerance tests before and after intervention. Magnetic resonance imaging and single voxel proton magnetic resonance spectroscopy were used to assess body fat mass and distribution, liver fat, and liver iron content.
Weight loss was successful in all groups (mean 3.3±o.5 kg; p<0.0001). Participants in all groups also had improved glucose tolerance and insulin sensitivity (p<0.001) and reduced body and visceral fat mass (p<0.001). These changes did not differ between groups.
In addition, liver fat content significantly decreased (p<0.001) with no between-group differences. This decrease was associated with the reduction in ferritin during intervention (r2, 0.08; p=0.0021). An independent lifestyle intervention study (Tuebingen Lifestyle Intervention Program; n=229; p=0.0084) confirmed this association.
“Epidemiological studies suggest that an increased red meat intake is associated with a higher risk of type 2 diabetes, whereas an increased fibre intake is associated with a lower risk,” the investigators noted.