Pre-ingestive influences on feeding

Joshua B Jones, Purdue University

Abstract

Feeding is recognized to be a multifaceted process, involving cognitive and physiological processes, as well as food properties. This dissertation examines the effects of food form, flavor, and variety as well as the effects of personality and learning on feeding. These effects were studied utilizing two separate randomized trials: the first a peanut consumption trial and the second a study utilizing a preload design and a learning intervention with chocolate-flavored snacks. The peanut intervention involved 151 participants consuming peanuts daily for 12 weeks, given as 42 grams of one flavor or as 14-gram servings of three different flavors. Participants maintained high levels of compliance to the protocol and liking of the peanuts, whether receiving the monotony or variety treatments, yet variety did not significantly improve either. Personality traits showed few relationships to eating behaviors in this study. Participants at greater risk of cardiovascular disease had significantly greater reductions of diastolic blood pressure, cholesterol, and triglycerides than those at lower risk. No single flavor differentially altered body composition, heart rate, or blood indices in the total sample. With peanuts, food variety, food flavor, and consumer attributes had little impact on consumption and health effects. During the second study, 107 participants participated in baseline preload testing, consuming chocolate beverages and snacks differing in food form and energy content, consuming a challenge meal, and recording eating events and ingestive behaviors on the days of consumption. After this, participants consumed one of these preloads daily for two weeks, and the initial testing was repeated to determine whether the intervention led to dietary learning in the form of adjusted eating behaviors. Learning was not evidenced as neither lean nor obese participants were able to adjust dietary compensation after repeated exposure to a test load. Lean participants were able to better compensate for energy in solid foods than obese participants at the study onset, but beverages were problematic for all individuals. This suggests that energy-containing beverages may be problematic for energy balance. Obese participants displayed greater stress and disordered eating attitudes, suggesting that these factors may account for the differential responses to energy in solid foods between lean and obese consumers. Food form was demonstrated to be an important determinant of ingestive behavior in this study, and although dietary learning was not evidenced, future interventions may elucidate the impact of learning on improvements in energy compensation. Overall, flavor, variety, and learning effects were not significant in the current studies, but they have proven important in the literature. Flavor and variety were likely ineffective at improving peanut liking and intake because the levels of both were quite high at the onset of the study. Learning gained from repeated exposures to solid and beverage forms of foods was not effective at modulating appetitive responses; compensation to the energy from the test loads did not improve; and either a longer conditioning period or a different learning paradigm is necessary to develop appropriate responses to beverage energy. Future work should continue to focus on appetitive responses subsequent to consumption of beverages.

Degree

Ph.D.

Advisors

Mattes, Purdue University.

Subject Area

Food Science|Behavioral psychology|Nutrition

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