All Volumes (2001-2008)


Volume I, 2001

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The role of dietary carbohydrates, dietary fat, and body fat in the regulation of sleep and tiredness was determined by studying sleep and tiredness in nineteen female subjects of different body compositions. It was hypothesized that dietary fat and body fat interact to cause an increase in sleep and tiredness. Subjects were healthy college students between the ages of 18 and 25 years old. This study was dual-phased. Phase I involved a 21 day record of normal hours slept per day and self-reported tiredness. In Phase II, the subjects consumed both a high-fat and high-carbohydrate diet for five days (for a total of 10 days). Phase I found no correlation between body fat percentage and sleep during the control (mixed carbohydrates, fat, and protein) diet. An insignificant negative correlation was found between body fat percentage and tiredness ratings, but this was likely due to psychological factors or chance. The results from Phase II suggest that both dietary fat and carbohydrates consistently decrease sleep and increase tiredness in high-fat individuals. The primary effect of dietary fat and carbohydrates appears to be a decrease in the hours of sleep. The effect on tiredness may be a secondary response to sleep deprivation, or may be independently effected by diet. The data cannot support or contradict that tiredness differences exist for high body fat subjects who obtain similar hours of sleep during different meal composition diets, because sleep varied for each diet. The results suggest that dietary fat interacts with body fat to increase tiredness, while at the same time decreasing sleep. Surprisingly, carbohydrates also appear to interact with body fat to decrease sleep and increase tiredness. Dietary fat, however, increased tiredness to a much larger extent than dietary carbohydrates. High body fat subjects invariably obtained less sleep and higher tiredness ratings on high-fat low-carbohydrate and high-carbohydrate low-fat diets, but lower body fat individuals were not consistently effected to a great extent. In comparison to carbohydrates, dietary fat had a greater sleep depriving effect and tiredness was dramatically increased in high body fat subjects. The conclusion of this study is that high body fat individuals can decrease their tiredness and increase sleep by avoiding high-fat and high carbohydrate diets.