Doctor of Philosophy (PhD)


School of Nutrition and Food Sciences

Document Type



The objective of these studies was to examine the effects of oat-based cereals and a spinach extract, on eating behavior. The cereals compared included instant oatmeal (IO), old fashioned oatmeal (SO), and a ready to eat cereal (RTEC), each containing the soluble fiber beta-glucan. The spinach extract containing thylakoids, the internal photosynthetic membrane of plants, was compared with a placebo. The first study, a randomized crossover trial compared the effect of IO and SO on subjective ratings of satiety, with the RTEC. Subjects consumed isocaloric 150kcal servings of the cereals in random order. Visual analogue scale ratings evaluating satiety were completed before breakfast and throughout the morning. IO increased satiety compared to the RTEC (p<0.05); however, SO was not as effective. The second study using a similar design compared the effect of isocaloric 250kcal servings of IO and the RTEC, on subjective ratings of satiety and food intake. IO increased subjective satiety (p<0.01) and decreased energy intake at lunch compared to the RTEC (p=0.012). The content and physicochemical properties of beta-glucan were determined in both studies. IO and SO had higher meal viscosities than the RTEC. IO also displayed higher initial meal viscosity than the RTEC. In the third randomized cross-over trial, subjects consumed the spinach extract or placebo in random order. Subjective ratings of satiety, liking and wanting (reward components of eating behavior), and food intake were evaluated. Compared to the placebo, consumption of the spinach extract increased satiety over a two hour period (p < 0.05); however, there were no differences in measures of liking or wanting, and energy intake measured at four hours. Although not significant, males reduced their energy intake by 126 kcals (p=0.08) after consuming the spinach extract, compared to the placebo. In conclusion, instant oatmeal in 150kcal and 250kcal portion sizes increases subjective satiety over four hours, compared to the RTEC; whereas, the 250kcal serving also reduces energy intake. Initial meal viscosity of oatmeal may be an important factor influencing satiety. While 5g of thylakoids increase subjective satiety over two hours compared to a placebo, the reward components, or energy intake are not different.



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Committee Chair

Greenway, Frank

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Life Sciences Commons