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- All Subjects: Intermittent Fasting
- Creators: Johnston, Carol
- Resource Type: Text
Circadian misalignments in terms of eat and sleep cycles, common occurrences among college students, are linked to adverse health outcomes. Time-restricted feeding, a form of intermittent fasting, may offer an exciting, non-pharmacologic approach to improve the health of this population by restricting eating to feeding windows that align with circadian biology. This study aims to fill a gap in the literature regarding the effect of early time-restricted feeding (eTRF) on college students, particularly in regard to diet quality, diet self-efficacy, and sleep quality. To test the hypothesis that eTRF would lead to an increase in all three variables, a 4-wk randomized-controlled, parallel arm trial was conducted. Thirty-five healthy college students were randomly assigned to one of two groups: the intervention group (TRF) was instructed to adhere to an 8-h feeding window aligned with the light cycle (9 am to 5 pm), and the control group (CON) was instructed to adhere to a 12-h feeding window typical of college students (10 am to 10pm). The eTRF diet was consumed ad libitum, and the participants were not instructed to avoid compensatory hyperphagia. The results showed a strong, reverse effect of eTRF on diet quality: fasting had a highly significant association with decreased diet quality. The results suggest that, under free-living conditions, college students practicing eTRF are more likely to compensate for prolonged fasting with unhealthy eating and snacking.
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.