Objective:The present study was aimed to verify the correlation between muscle mass index(MMI)and body mass index(BMI)in aging population and to verify the effects of a diet rich in proteins on muscle mass loss.Methods:747 patients(533 females,62-75years old)were studied.Nutritional status was assessed.Muscle mass(MM)was estimated.MMI was calculated as:MM/height2 in normal weight(NW)and obese(OB)aging groups.149 OB peoples(106 females)were treated with a hypocaloric diet moderately rich in proteins(1,2 g/Kg/die)for six months.Results:MMI was significantly different in males and females,comparing OB and NW groups.In OB males BMI was 33,8±4,3Kg/m2 and MMI was 10,3±1,2Kg/m2;in OB females BMI was 35,1±5,3 Kg/m2 and MMI was 8,5±1,1 Kg/m2.In NW males BMI was 26,3±2,6Kg/m2 and MMI was 9,6±0,8 Kg/m2;in NW females BMI was 26,4±2,2Kg/m2 and MMI was 7,4±0,6Kg/m2.At the end of dieting,BMI was significantly reduced in OB groups(Males:30,2±3,3vs33,6±4,2 kg/m2;females:32,9±4,5vs35,7±5,4kg/m2,baseline).MMI was 9,9±1,1vs10,1±1,1 kg/m2,in OB males,while 8,4±1,1vs8,5±1,1 kg/m2 in OB females.The arm muscular area(AMA)did not show a significant decrease in OB groups(Males:62,8±9,8vs63,9±12,9kg/m2;females:52,4±13,1vs53,1±12,4kg/m2,baseline).

Conclusions:MMI was significantly different in males and females,comparing OB and NW groups.In particular,MMI in our OB patients was higher than in NW peoples.A diet rich in proteins for six months was able to prevent muscle mass loss in OB aging peoples.