Effect of habitual dietary-protein intake on appetite and satiety

To investigate whether appetite response to a high-protein test meal varies inversely with habitual protein intake, the satiating influence of dietary protein was investigated in 14 subjects. Subjects were divided into two gr oups on the basis of habitual protein intake: means of 1.0 g/kg/day (LP) an d 1.4 g/kg/day (HP). Appetite was assessed in each group following high pro tein meals (test a). A 13-day period of dietary manipulation increased diff erences in protein intake between groups to a mean of 0.75 g/kg/day (LP) an d 1.96 g/kg/day (HP) and a second satiety test (b) was performed. A third l est (c) was performed in the HP group after protein intakes were reduced fo r 2 days to a mean of 0.85 g/kg/day. Differences in satiety were most marke d, with significant correlations between satiety after the three meals and daily protein intake (r = -0.36). LP satiety was significantly greater than HP after test b (p = 0.025), and approached significance when satiety resp onse during LPb was compared with HPc (p = 0.07). Results support the hypot hesis that the satiating effect of dietary protein varies inversely with ha bitual protein intake. (C) 2000 Academic Press.