QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Theall, C. L. Articles by Wurtman, R. J. Search for Related Content PubMed PubMed Citation Articles by Theall, C. L. Articles by Wurtman, R. J.

Self-Selection and Regulation of Protein:Carbohydrate Ratio in Foods Adult Rats Eat¹

Laboratory of Neuroendocrine Regulation, Massachusetts Institute of Technology, Bldg. E25-604, Cambridge, MA 02139

When adult rats were offered isocaloric diet pairs, which differed in carbohydrate contents and which contained the same or differing protein contents, the animals chose between the two foods nonrandomly. The overall ratio of protein to carbohydrate consumed was maintained between 0.20 and 0.43, while the range of possible protein:carbohydrate ratios that the animals could have eaten was much broader, i.e., 0.07–3.60. If diet choice was restricted to pairs containing very large proportions of carbohydrate (average wt/wt % of pair greater than 57%), the regulation of the dietary carbohydrate intake was disturbed: much more carbohydrate was eaten, and the protein:carbohydrate ratio was decreased. These observations suggest that there may be an intrinsic requirement for dietary carbohydrate, and that this requirement may be related to the amount of protein concurrently being consumed. The protein:carbohydrate ratio that the animals choose, when allowed the choice, is also the proportion previously shown to produce neither a decrease nor an increase in brain serotonin levels. It is thus possible that the mechanism by which the brain controls nutrient choice involves alterations in serotonin synthesis, causing foods to be selected that will maintain the release of this transmitter at "optimal" levels.

KEY WORDS: • protein:carbohydrate ratio • food selection • serotonin • carbohydrate

¹ These studies were supported in part by grants from the National Aeronautics and Space Administration and the Center for Brain Sciences and Metabolism Charitable Trust. Ms. Theall was supported by a training grant (MH-13449) from the National Institutes of Health.

² To whom reprint requests should be sent at M.I.T. address.

Manuscript received 3 August 1983.

This article has been cited by other articles:

				P. J. Morris, E. L. Calvert, K. L. Holmes, R. M. Hackett, and J. M. Rawlings Energy Intake in Cats as Affected by Alterations in Diet Energy Density J. Nutr., July 1, 2006; 136(7): 2072S - 2074S. [Full Text] [PDF]