Methionine restriction plus overload improves skeletal muscle and metabolic health in old mice on a high fat diet.

Methionine restriction (MR) has been shown to reduce the age-induced inflammation. We examined the effect of MR (0.17% methionine, 10% kCal fat) and MR + high fat diet (HFD) (0.17% methionine, 45% kCal fat) on body mass, food intake, glucose tolerance, resting energy expenditure, hind limb muscle mass, denervation-induced atrophy and overload-induced hypertrophy in young and old mice. In old mice, MR and MR + HFD induced a decrease in body mass. Muscle mass per body mass was lower in old compared to young mice. MR restored some of the HFD-induced reduction in muscle oxidative capacity. The denervation-induced atrophy of the m. gastrocnemius was larger in animals on MR than on a control diet, irrespective of age. Old mice on MR had larger hypertrophy of m. plantaris. Irrespective of age, MR and MR + HFD had better glucose tolerance compared to the other groups. Young and old mice on MR + HFD had a higher resting VO per body mass than HFD group. Mice on MR and MR + HFD had a resting respiratory quotient closer to 0.70, irrespective of age, indicating an increased utilization of lipids. In conclusion, MR in combination with resistance training may improve skeletal muscle and metabolic health in old age even in the face of obesity.