. 2021 Jul 23;13(8):2525. doi: 10.3390/nu13082525

Table 2.

Study Characteristics of Included Papers on Day-time Time Restricted Eating.

Citation	Study Conditions	N	Population Characteristics	Cortisol Response
Jamshed et al. 2019 [40]	Eleven overweight adults participated in a 4-day randomized crossover study where they ate between 8 a.m. and 2 p.m. (early TRF (eTRF)) and between 8 a.m. and 8 p.m. (control schedule). Blood samples were collected in the fasting state at 20:00 on day 3 (evening, p.m.) and immediately after exiting the chamber at ~07:30 on day 5 (morning, a.m.). The evening blood draws were taken immediately before dinner in the control arm.	11	4 females, 7 males Average age (years): 32 ± 7 years. Average BMI (kg/m²): 30.1 ± 2.7	Increased morning cortisol levels but was not significant (p = 0.10), significantly decreased evening cortisol levels (p = 0.03).
McAllister et al. 2020 [41]	8 h feeding window. No restrictions on what time of day this was to be performed. Pre and Post TRE results were recorded, groups separated into isocaloric and no caloric restriction. Blood samples were collected between 05:00 and 09:00 following at least an 8 hr fast via venipuncture and finger prick. 28-day protocol.	22	22 adult males. Average age (years): 22 ± 2.5 Average BMI (kg/m²): 28.5 ± 8.3.	TRE + No Caloric Restriction led to reduction in Cortisol (39.8 to 37.3 ug/dL, not T-tested). Isocaloric TRE led to rise in cortisol (31.8 to 35.2 ug/dL, not T-tested).
Stratton et al. 2020 [42]	Results for Pre and Post TRE (breakfast skipping) + 25% Caloric restriction + regular resistance training vs. No time restriction +25% caloric restriction + resistance training. Cortisol assessments were taken at the same approximate time pre- and post-intervention (±2 h), time from the waking hour was not quantified, which may have also affected the measurement	26	26 Males Average age (years): 22.9 ± 3.6 Average BMI (kg/m²): not provided	TRE + Caloric restriction + reg. resistance training led to reduction in cortisol (118.3 to 106.1 ng/mL). No time restriction led to increase in cortisol (119.2 to 150.7 ng/ML). Both p = <0.05
Witbracht et al. 2015 [29]	Observational Study acquired those already performing TRE (breakfast skippers). Salivary cortisol taken 6 times throughout the day + waking and bedtime for one day for both case and control.	65	65 Females Age range: 18–45 (mean not provided) Average BMI (kg/m²): 24.8 ± 6.7	TRE (breakfast skippers) demonstrated decreased morning (waking) cortisol, elevated midday mid-day cortisol, and no significant evening differences compared to the control group.