Publication Date


Document Type


First Advisor

Parham, Ellen S.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Human and Family Resources


Snack foods; Carbohydrates; Nutrition--Psychological aspects; Tryptophan


It has been postulated that the brain neurotransmit- ter serotonin may be involved in the regulation of appetite for carbohydrate and may influence other brain functions such as sleep and mood state. This study investigated the effects of meals known to increase and inhibit the synthesis of brain serotonin, on carbohydrate snacking and ratings of alertness, hunger and food preference. Twelve women who were evaluated to be carbohydrate cravers participated in the study. Two treatment meals, CHO + TRP (high-carbohydrate + 1 gm tryptophan) and PRO + Placebo (high-protein + 1 gm fructose), were administered at least 28 days apart. Prior to the treatment meal (pre-test) and at one, two and three hours after the treatment meal (post-tests), subjects completed a series of questionnaires designed to measure subjective alertness, hunger and food preference (desire for chocolate, sweets and starch). A snack tray consisting of sweet and starchy carbohydrate snack foods was presented for taste evaluation one and one-half hours after the treatment meal. Outcome effects of the treatment meals were measured by 1) snack consumption (the percent of total calories consumed and the percent of sugar and starch calories consumed) and 2) hourly ratings of alertness, hunger and food preference. An analysis of variance revealed no significant effect of the treatment meals on snack consumption in the group as a whole; however, four subjects did reduce their snack intake after the CHO + TRP meal. An analysis of covariance for repeated measures revealed no effect of the treatment meal, time or their interaction on ratings of alertness or the desire for starch. An effect of time (p < 0.01) was observed on the rating of hunger and the desire for chocolate and sweets; however, no effect of the treatment meal or the interaction of treatment meal and time were observed for these variables. During the PRO + Placebo meal, greater differences between the 1-hour and 2-hour post-treatment mean scores were observed in the desire for chocolate, sweets and starch than during the CHO + TRP meal. These observations provided no evidence that a CHO + TRP meal, and the subsequent rise in brain serotonin, reduces subjective preference for carbohydrates.


Includes bibliographical references (pages [94]-100)


viii, 147 pages




Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type