In young subjects , a dose-responsive suppression ( SEM ) of energy intake was found at the buffet meal by protein ( suppression at 30 kcal : 7 8 % , P = 0.189 ; 90 kcal : 17 8 % , P = 0.054 ; 180 kcal : 33 7 % , P = 0.002 ) , whereas suppression was observed only after the 180-kcal load in older subjects ( 30 kcal : 7 4 % increase , P = 0.126 ; 90 kcal : 6 7 % increase , P = 0.291 ; 180 kcal : 17 6 % suppression , P = 0.016 ) .