Year of Publication


Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation


Public Health



First Advisor

Dr. John F. Watkins


The impact of diet and exercise on overall health and chronic disease risk has been well examined. Multiple studies show that Americans eat more now than they did fifty years ago. What isn’t known is how much of an impact time has on food intake patterns of individuals in terms of different age groups, historic periods of structural influences, and birth cohorts.

In order to identify the impact of time on food intake this study examined time from multiple perspectives. The first aim of this study was to determine food intake patterns among age groups across five time periods using a cross-sectional approach. The second aim of this study was to use a cohort perspective to measure food intake patterns among three birth cohorts across five time periods. The third aim of this study was to break down observed food patterns by group characteristics such as ethnicity, gender, income, education level, and marital status. The final aim of this study was to analyze the findings from the first three aims through a time context using historic information to connect individuals with socioecological factors that influence age and period-specific food knowledge, perceptions, decisions, and behaviors.

Using data from five NHANES survey analyses confirms that total calorie and macronutrient intake has increased over the past fifty years. In addition, this study found that increased consumption occurred in all age groups. Within all five time periods, macronutrient intake declined with advancing age. When comparing birth cohorts over time, all cohorts in this study hit their peak intake of macronutrients and total calories in the years 2001 and 2011. Protein and fat intake was higher in those under the age of 50 while carbohydrate intake was highest in those over the age of 50. Using the life course framework, these factors were examined simultaneously. Results of this study are unique among food intake research because they incorporate not only socioecological influences but also life span and life course perspectives. This holistic approach will provide significant insight into food choice and behavior which has previously been absent from food intake studies.

Digital Object Identifier (DOI)