Theses and Dissertations
This collection includes both ASU Theses and Dissertations, submitted by graduate students, and the Barrett, Honors College theses submitted by undergraduate students.
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- All Subjects: Fasting
- Creators: Johnston, Carol
Description
Ketone bodies are produced in the liver from the acetyl CoA derived from fatty acids that cannot enter the Krebs cycle. This is a sub-analysis of a larger study which had numerous outcome markers. This analysis focuses on the relationship between ketone blood levels and cognition. The study looked at the relationship between Time Restricted Feeding (TRF), a method of intermittent fasting. TRF is something that can be easily adapted into an individual’s lifestyle and has been shown to have multiple advantages. This 8-week study began with 23 enrolled participants, but due to COVID-19 only 11 participants could be tested for cognition and blood ketone levels after week 4. All participants had similar ranges of weight, height, age, BMI, hip, and waist measurements at baseline. Moreover, these demographic variables were not related to ketone levels or cognition. The data indicate that ketone bodies increased in participants practicing TRF and that the increase in ketone bodies in the blood, specifically β-hydroxybutyrate was strongly correlated to increased cognitive function. This is consistent with theories that elevated ketone levels allowed for early hunter-gather communities and other mammals to survive prolonged periods of nutrient deprivation while keeping high cognitive function.
ContributorsTaha, Basel Mahmoud (Author) / Johnston, Carol (Thesis director) / Karen, Sweazea (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Background: College students face a particularly high prevalence of body dissatisfaction and weight instability increasing the risk of being unhappy and having a poor quality of life. Time-restricted feeding, a type of intermittent fasting, has gained popularity recently for sustainable weight loss without the characteristic dietary restrictions of most fad diets. A limited number of randomized control trials have looked at the effects of time-restricted feeding in humans, but none have looked at how this dietary regimen impacts happiness and quality of life. Objective: The goal was to examine the effects of an 18-hour daily fasting regimen compared to an 8-hour daily fasting regimen on happiness and quality of life in college students in Arizona.
Methods: Participants included 29 healthy, non-smoking, non-vaping students attending college in Arizona between October 2020 to March 2021. Of the 16 participants allocated to the time-restricted feeding intervention, 8 completed the trial. Of the 13 participants allocated to the control group, 10 completed the trial. The eating window began within one hour of waking up with a 6-hour eating window for the intervention group and 16-hour window for the control group. They could do one cheat day per week. No dietary restrictions were enforced. Participants completed the Oxford Happiness Questionnaire and the WHOQOL-BREF quality of life questionnaire at baseline, week 4, and week 8. Week 8 data were not reported due to data collection changes and cancellations related to the new safety protocols for the COVID-19 pandemic.
Results: Quality of life related to social relationships improved significantly in the intervention group (p=0.026). There was a trend favoring the intervention group as well showing a possible improvement in happiness related to perceived energy levels (p=0.088). No other significant data were reported.
Conclusion: Adherence to an 18-hour time-restricted feeding regimen for 8 weeks may improve quality of life related to social relationships in college students in Arizona. The results of this trial do not suggest a significant impact on overall quality of life or happiness in this population.
ContributorsDe León, Anateresa (Author) / Johnston, Carol (Thesis advisor) / Shepard, Christina (Committee member) / Grant, Shauna (Committee member) / Arizona State University (Publisher)
Created2021
Description
ABSTRACT
Background. College students’ modifiable health behaviors, including unhealthful eating patterns, predispose them to risk for future cardiometabolic conditions.
Purpose. This novel 8-week randomized control parallel-arm study compared the effects of a daily 18-hour Time-Restricted Feeding protocol vs. an 8-hour fast on diet quality in college students. Secondary outcomes were resting morning blood pressure, biomarkers of glucose regulation, biomarkers of lipid metabolism, and anthropometric measures.
Methods. Eighteen healthy college students (age = 23 ± 4 years; BMI = 23.2 ± 2.3 kg/m2; MET = 58.8 ± 32.9 min/wk) completed this study. Participants were randomized to a daily 18-hour fasting protocol (Intervention; n = 8) or a daily 8-hour fasting protocol (Control; n = 10) for eight weeks. One ‘cheat’ day was permitted each week. Outcomes were measured at weeks 0 (baseline), 4, and 8. A non-parametric Mann Whitney U test was used to compare the week 4 change from baseline between groups. Statistical significance was set at p≤0.05.
Results. Diet quality (p = 0.030) and body weight (p = 0.016) improved from baseline to week 4 for the INV group in comparison to the CON group. The data suggest these improvements may be related to reductions in snacking frequency and increased breakfast consumption. Fasting blood glucose and hip circumference tended to improve for the INV group in comparison to the CON group (p = 0.091 and p = 0.100). However, saturated fat intake tended to increase in the INV group in comparison to the CON group (p = 0.064). Finally, there were no treatment differences between groups (p>0.05) for the 4-week change in total calories, dietary vitamin C, added sugars, resting systolic blood pressure, resting diastolic blood pressure, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), low-density lipoprotein (LDL) cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, waist circumference, or MET.
Conclusion. These data, although preliminary, suggest that the 18-hour fasting protocol was effective for improving diet quality and reducing weight in comparison to the 8-hour fasting protocol in healthy college students. Future intervention trials will need to confirm these findings and determine the long-term relevance of these improvements for health outcomes.
Background. College students’ modifiable health behaviors, including unhealthful eating patterns, predispose them to risk for future cardiometabolic conditions.
Purpose. This novel 8-week randomized control parallel-arm study compared the effects of a daily 18-hour Time-Restricted Feeding protocol vs. an 8-hour fast on diet quality in college students. Secondary outcomes were resting morning blood pressure, biomarkers of glucose regulation, biomarkers of lipid metabolism, and anthropometric measures.
Methods. Eighteen healthy college students (age = 23 ± 4 years; BMI = 23.2 ± 2.3 kg/m2; MET = 58.8 ± 32.9 min/wk) completed this study. Participants were randomized to a daily 18-hour fasting protocol (Intervention; n = 8) or a daily 8-hour fasting protocol (Control; n = 10) for eight weeks. One ‘cheat’ day was permitted each week. Outcomes were measured at weeks 0 (baseline), 4, and 8. A non-parametric Mann Whitney U test was used to compare the week 4 change from baseline between groups. Statistical significance was set at p≤0.05.
Results. Diet quality (p = 0.030) and body weight (p = 0.016) improved from baseline to week 4 for the INV group in comparison to the CON group. The data suggest these improvements may be related to reductions in snacking frequency and increased breakfast consumption. Fasting blood glucose and hip circumference tended to improve for the INV group in comparison to the CON group (p = 0.091 and p = 0.100). However, saturated fat intake tended to increase in the INV group in comparison to the CON group (p = 0.064). Finally, there were no treatment differences between groups (p>0.05) for the 4-week change in total calories, dietary vitamin C, added sugars, resting systolic blood pressure, resting diastolic blood pressure, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), low-density lipoprotein (LDL) cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, waist circumference, or MET.
Conclusion. These data, although preliminary, suggest that the 18-hour fasting protocol was effective for improving diet quality and reducing weight in comparison to the 8-hour fasting protocol in healthy college students. Future intervention trials will need to confirm these findings and determine the long-term relevance of these improvements for health outcomes.
ContributorsMayra, Selicia (Author) / Johnston, Carol (Thesis advisor) / Sears, Dorothy (Committee member) / Swan, Pamela (Committee member) / Sweazea, Karen (Committee member) / Wharton, Christopher (Christopher Mack), 1977- (Committee member) / Arizona State University (Publisher)
Created2020
Description
The popularity of intermittent fasting has grown in recent years and is a commonly discussed diet topic on the internet and social media. Time-restricted feeding (TRF) is one particular intermittent fasting regime that allows participants to pick windows of time per day in which they can eat or fast. While current randomized controlled trials show positive effects of TRF on weight loss, body composition, glucose, insulin, and blood pressure, there is a gap in the literature of the its effect on cognition although animal studies suggest a positive effect. The purpose of this 8-week randomized controlled trial was to investigate the effect of 18-hour time-restricted feeding on healthy, Arizona State university students. Students (n= 29) were recruited by the research team and were randomized to either an 18-hour intervention (INV) group or an 8-hour control (CON) group. INV participants were instructed to consume food within the first hour of waking and cease their eating period after 6 hours to begin their 18-hour fast. Participants were not given any other dietary restrictions and were allowed to eat ad libitum during their eating periods. Cognitive tests (Stroop Test and Trail Making Test) and blood draws were taken at baseline, week 4, and week 8. The present study demonstrated high attrition, with 7 participants dropping out of the study after their baseline visit. Interruption of the COVID-19 pandemic also impacted the data analysis, with the removal of week 8 data. Despite limitations, statistically significant differences between the INV group and CON group were seen in the Trail Making Test B at week 4 (p= 0.031). Statistically significant differences were not seen in any of the other cognitive outcomes measured (Stroop Test, Trail Making Test A, serum BDNF, serum ketones). However, a significant inverse relationship was seen between serum ketones and Trail Making Test B. In conclusion, this study suggests that TRF may have a favorable effect on cognitive acuity among university students.
ContributorsKravat, Natalie (Author) / Johnston, Carol (Thesis advisor) / Gu, Haiwei (Committee member) / Sears, Dorothy (Committee member) / Arizona State University (Publisher)
Created2021