Abstract | OBJECTIVE: 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 carbohydrate. 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 weight loss at 12 weeks in study 1. Ad libitum caloric intake fell by 441 +/- 63 kcal/ day with a 4.9 +/- 0.5 kg weight loss 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 carbohydrate or protein consumption that preceded the ad libitum administration of the 2 diets. CONCLUSION: An increase in either carbohydrate or protein intake increases satiety and leads to significant weight loss, however, these effects are not mediated by an increase in plasma concentration of Trp or the Trp:LNAA ratio.
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Authors | Mikhail S Koren, Jonathan Q Purnell, Patricia A Breen, Colleen C Matthys, Holly S Callahan, Kaatje E Meeuws, Verna R Burden, David S Weigle |
Journal | Annals of nutrition & metabolism
(Ann Nutr Metab)
Vol. 51
Issue 2
Pg. 182-7
( 2007)
ISSN: 1421-9697 [Electronic] Switzerland |
PMID | 17541265
(Publication Type: Journal Article, Research Support, N.I.H., Extramural)
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Copyright | Copyright 2007 S. Karger AG, Basel. |
Chemical References |
- Amino Acids
- Dietary Carbohydrates
- Dietary Fats
- Dietary Proteins
- Tryptophan
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Topics |
- Adult
- Amino Acids
(blood)
- Appetite
(drug effects)
- Diet, Reducing
- Dietary Carbohydrates
(administration & dosage)
- Dietary Fats
(administration & dosage)
- Dietary Proteins
(administration & dosage)
- Energy Intake
- Female
- Humans
- Male
- Middle Aged
- Obesity
(blood, diet therapy)
- Satiation
(drug effects, physiology)
- Treatment Outcome
- Tryptophan
(blood)
- Weight Loss
(drug effects, physiology)
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