Twenty-four healthy young ( aged @ @ y , body mass index @ @ kg/m ( @ ) ) and @ older ( aged @ @ y , body mass index @ @ kg/m ( @ ) ) men received a primed continuous L - -LSB- ring - ( @ ) H@ -RSB- - phenylalanine and L - -LSB- ring-@ ,@ - ( @ ) H@ -RSB- - tyrosine infusion and ingested @ g intrinsically L - -LSB- @ - ( @ ) C -RSB- - phenylalanine-labeled protein with ( Pro + CHO ) or without ( Pro ) @ g carbohydrate .