OBJECTIVE: @entity750 mediates satiety in the central nervous system. Brain @entity750 content depends on the plasma ratio of @entity2340 (Trp) to large neutral @entity1522 (LNAA) and may be affected by diet composition. We examined whether high- @entity1735 or high-protein diets induce satiety and @entity353 by altering plasma concentrations of these @entity1522 . METHODS: In study 1 (n = 16, BMI = 27.0 +/- 2.3), we compared plasma Trp and LNAA concentrations averaged over 24 h after 2 weeks of consuming isocaloric diets containing either 45 or 65% of total energy as @entity1735 . In study 2 (n = 19, BMI = 26.2 +/- 2.1), we made the same measurements following diets containing either 15 or 30% of total energy as protein. To assess satiety in both studies, we recorded caloric intake and weight changes during a subsequent 12-week period of ad libitum consumption of the experimental diets. RESULTS: Ad libitum caloric intake fell by 222 +/- 81 kcal/day with a 3.7 +/- 0.6 kg @entity353 at 12 weeks in study 1. Ad libitum caloric intake fell by 441 +/- 63 kcal/ day with a 4.9 +/- 0.5 kg @entity353 at 12 weeks in study 2. The 24-hour averaged plasma concentration of Trp and the Trp:LNAA ratio were unaffected by the isocaloric increase in @entity1735 or protein consumption that preceded the ad libitum administration of the 2 diets. CONCLUSION: An increase in either @entity1735 or protein intake increases satiety and leads to significant @entity353 , however, these effects are not mediated by an increase in plasma concentration of Trp or the Trp:LNAA ratio.

Changes in plasma amino Acid levels do not predict satiety and XXXX on diets with modified macronutrient composition.

@entity1522 :: ('CHEBI:33709', 'Chemical') :: ['amino acids'] @entity353 :: ('MESH:D015431', 'Disease') :: ['weight loss'] @entity1735 :: ('CHEBI:16646', 'Chemical') :: ['carbohydrate'] @entity2340 :: ('CHEBI:27897', 'Chemical') :: ['tryptophan'] @entity750 :: ('MESH:D012701', 'Chemical') :: ['serotonin', 'Serotonin']
@entity353 :: (MESH:D015431,Disease) :: ['weight loss']
