Time Restricted Eating With Physical Activity for Weight Management
Phase: NA
Conditions: Pre Diabetes, Overweight and Obesity
Sponsor: University of Illinois at Chicago

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Time restricted eating with physical activity for weight management 
 
 
 
Principal investigator: 
Kelsey Gabel, Ph.D., RD 
Clinical Assistant Professor and Postdoctoral Researcher 
Department of Kinesiology and Nutrition 
University of Illinois, Chicago 
1919 West Taylor Street, Room 532 
Chicago, Illinois, 60612 
Tel: 312.413.8911 
Email: kdipma2@uic.edu 
 
Study location: 
Human Nutrition Research Unit 
1919 West Taylor Street, Room 121C 
Chicago, Illinois, 60612 
 
Coalition Strength and Conditioning 
2051 W Carroll Ave 
Chicago, IL 60612 
Sponsor: 
No sponsor. 
 
Version 4 
 
July 19, 2021 

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1.0 Eligibility 
Older adults with overweight or obesity will be recruited by flyers posted around the University of Illinois at 
Chicago (UIC) campus and on social media. Subject eligibility will be assessed and determined by Kelsey 
Gabel Ph.D., R.D. Screening will be conducted in-person at the Human Nutrition Research Unit (HNRU) 
located in the Applied Health Sciences Building (1919 West Taylor St, Room 121C). 
1.1 Inclusion criteria: 
• 
Age between 50 to 70 years old 
• 
BMI between 25 and 50 kg/m2 
• 
Pre-diabetic (fasting glucose: 100-125 mg/dl or HBA1c 5.7%-6.4%) 
• 
Sedentary or lightly active 24 
• 
Are post menopausal (absence of menstural cycle for 1 year) 
1.2 Exclusion criteria: 
• 
Diabetic (fasting glucose: >126 mg/dl or HBA1c >6.5%) 
• 
Have a history of eating disorders (anorexia, bulimia, or binge eating disorder) 
• 
Have uncontrolled hypertension, any other cardiovascular disease, or history of aneurysm 
• 
History of alcohol dependance (score >20 from Alcohol and Health Questionnaire)25 
• 
Are not weight stable for 3 months prior to the beginning of study (weight gain or loss > 4 kg) 
• 
Are not able to keep a food diary or activity log for 7 consecutive days during screening 
• 
Are taking drugs that influence study outcomes (weight loss, glucose-lowering medications) 
• 
Are premenopausal, perimenopausal or have an irregular menstrual cycle (menses that does not 
appear every 27-32 days) 
• 
Mobility disability (unable to exercise for 40-60 minutes 3-5 days/week) 
• 
Diagnosed comorbidities including systemic diseases (Parkinson’s cirrhosis, renal disease or systemic 
rheumatic conditions), cancer, or cognitive impairment 
• 
Are night shift workers 
• 
Are smokers 
2.0 Subject enrollment 
Independently living subjects from the Chicago area will be recruited by flyers posted around the University 
of Illinois at Chicago (UIC) campus. The flyer will also be posted to social media outlets including: Instagram, 
Facebook, and Twitter. All study procedures will be conducted at the Human Nutrition Research Unit 
(HNRU) located in the Applied Health Sciences Building (1919 West Taylor St, Room 121C) . 
Each subject will attend 1 screening visit. During Visit 1 subjects will be screened by the Study Manager, 
Kelsey Gabel Ph.D., RD, via questionnaire, which will assess eligibility based on the requirements listed 
above. The following parameters will also be assessed: body weight and height (for BMI), a blood draw (for 
fasting glucose/diabetic status). Alcohol and Health Screening questionnaire will be administered to 
determine history of alcohol dependence (questionnaire is attached to submission). The Study Manager 
will also distribute a 7-day food record and provide detailed instructions on how to complete the records. 
Follow-up with participants virtually will be scheduled 10 days after the first screening. The food record will 
be assessed for adequacy (to evaluate each participant's motivation to participate in the study) and fasting 
blood glucose (via glucometer) will be taken. Consent will be obtained prior to the administration of the 
screening questionnaire by a member of the study team (key research personnel identified in Appendix P). 
 
3.0 Study design and procedures 
A 10-week non-randomized, controlled, parallel-arm trial, divided into a 2-week baseline and an 8-week 
intervention will be implemented. Older subjects with overweight or obesity (n = 20) will be assigned to 1 

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of 4 groups: (1) TRE (n = 5) ad libitum food intake from 12 pm to 8 pm, fasting (with zero-calorie 
beverages) from 8 pm to 12 pm daily, (2) TRE + EN (n = 5), TRE diet as stated in group 1 plus 3-4 days of 40-
60 minutes of endurance exercise per week; or 3) TRE + RT (n = 5), TRE diet as stated in group 1 plus 3- 
4 days of 40-60 minutes of resistance training per week 4) control (n = 5), ad libitum food intake daily with 
no meal timing restrictions. In-person study activities will be carried out at the Human Nutrition Research 
Unit (HNRU) located in the Applied Health Sciences Building (1919 West Taylor St, Room 121C) or at 
Coalition Strength and Conditioning (2051 West Carroll Ave, Chicago IL 60612). 
Diet and exercise interventions 
 
Group 
Diet protocol 
Exercise protocol 
TRE 
(n = 50) 
8-h eating window 
Ad libitum food intake from 12-8 pm every day 
Fasting from 8-12 pm every day (16-h fast) 
None 
TRE + EN 
(n = 50) 
8-h eating window 
Ad libitum food intake from 12-8 pm every day 
Fasting from 8-12 pm every day (16-h fast) 
4 days/week, supervised 
60 minutes, Intensity: 85% HRmax 
TRE + RT 
(n = 50) 
8-h eating window 
Ad libitum food intake from 12-8 pm every day 
Fasting from 8-12 pm every day (16-h fast) 
4 days/week, supervised 
60 minutes, Intensity: 85% RPE 
Control 
(n = 50) 
Every day: Ad libitum fed 
No exercise 
Diet protocol 
TRE group and combination groups (8-h eating window): During the weight loss period, the TRE 
groups will be instructed to eat ad libitum from 12-8pm daily, and fast from 8-12 pm (16-h fast). During 
the 8-h eating window, there will be no restrictions on types or quantities of foods consumed. 
Moreover, participants will not be required to monitor caloric intake during this ad libitum feeding 
period. During the fasting period, participants will be encouraged to drink plenty of water and will be 
permitted to consume energy-free drinks, such as black tea, coffee, and diet sodas (limit 2 diet sodas/d, 
since these beverages may increase sugar craving 26). TRE participants will meet with the dietitian every 
week (by phone or zoom) throughout the weight loss period to review their diet adherence. Subjects 
will also be taught how to make healthy food choices that conform to ADA nutrition guidelines.27 

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Exercise protocol 
 
Study week 
Week 1-2 
Weeks 3-4 
Exercise bouts/week 
3 
4 
Endurance Training 
Time: 40-50min 
Intensity: 65-75% HRmax 
Time: 60 min 
Intensity: 85% HRmax 
Resistance Training 
Time: 40-50 min 
Intensity: 65-75% 1rm 
Protocol: 3x10-12reps 
Time: 60 min 
Intensity: 75-85% 1rm 
Protocol: 3x8-12reps 
Increase intensity by 5-10% of 1RM when needed 
Endurance exercise combination group: Only the TRE + EN combination group will partake in the 
endurance exercise training. Participants will be given two supervised endurance exercise options due 
to COVID-19, one in-person and one remote. Option 1 (in-person): All training sessions will be 
conducted at the HNRU. Subjects will participate in a supervised aerobic exercise program 3-4 times 
per week, 40-60 min/d, for 8 weeks.16,28 Exercise will be performed on an elliptical, stationary bike or 
rowing erg. Participants will be masked, exercise equipment will be placed ≥6ft apart and cleaned 
between use. During the week 1 sessions, subjects will exercise for 40 minutes at a moderate intensity 
(65% heart rate max (HRmax)). During the week 2 sessions, subjects will train for 50 minutes at a higher 
intensity (75% HRmax). For weeks 3-8, subjects will train for 60 minutes at an even higher intensity 
(85% HRmax). The participants will wear heart rate monitors (Fitbit Alta HR, Boston, MA) during each 
training session to provide visual feedback of their individualized target heart rate. Fitbit monitors will 
be distributed to subjects at each training session. Compliance with the training: A research assistant 
will be present to supervise all the training sessions. Exercise will be carefully documented through 
attendance at the training sessions. Subjects will be permitted to choose the day and time slot that 
works best for them. If a subject misses their session, they will be required to make up for it that same 
week. Subjects will be permitted to miss 4 sessions total during the 8-week intervention. 
 
Option 2 (remote): All training sessions will be conducted at the subject’s home. Subjects will 
participate in a supervised aerobic exercise program 3-4 times per week, 40-60 min/d, for 8 weeks.16,28 
Exercise will be performed by watching YouTube aerobic exercise (Zumba) videos at home. The video 
links will be provided by the study coordinator prior the exercise session. The coordinator conducting 
the study session on Zoom will have immediate knowledge of the subject's location so that they can 
relay this information to emergency personnel if needed. During the week 1 sessions, subjects will 
exercise for 40 minutes at a moderate intensity (65% heart rate max (HRmax)). During the week 2 
sessions, subjects will train for 50 minutes at a higher intensity (75% HRmax). For weeks 3-8, subjects 
will train for 60 minutes at an even higher intensity (85% HRmax). The participants will wear heart rate 
monitors (Fitbit Alta HR, Boston, MA) during each training session to provide visual feedback of their 
individualized target heart rate. Fitbit monitors will be distributed to subjects so that they can monitor 
their heart rate at home. Compliance with the training: A research assistant will be present to 
supervise all the training sessions over Zoom. All sessions will be pre-scheduled with the research 
assistant, so the participant knows when to enter the Zoom meeting to perform the activity. Exercise 
will be carefully documented through regular online attendance at the training sessions. Subjects will 
be permitted to choose the day and time slot that works best for them. If a subject misses their session, 
they will be required to make up for it that same week. Subjects will be permitted to miss 5 sessions 
total during the 24-week trial. 
Resistance training combination group (in-person): Only the TRE + RT combination group will partake 
in the resistance training exercise. All training sessions will be conducted in-person at the Coalition 

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Strength and Conditioning by Cole Cruz, MS, ACSM, CSCS. During the baseline period participants will 
attend two session prior to the intervention for familiarization and testing. The first session will be a 
familiarization session where the participant will be instructed on how to do the movements correctly 
and safely. The second session will test the participants’ 5rm of deadlift, box squat, overhead press, 
and bench press. 1RM estimates will be based off of the 5rm (80% of 1rm)29. Subjects will participate in 
a supervised resistance training program beginning with 3 times per week progressing to 4 times per 
week in weeks 3-8 16,30. Each session will be 40-60 min in duration and will continue for 8-weeks28,30,31. 
During RT session participants will perform a progressive periodized whole-body resistance exercise 
(exercise program attached to submission). During the first 2 weeks of the RT program, the participants 
will complete three sets of 10–15 repetitions of 65% of their 1 rep max. For the following 6 weeks, the 
training volume will be set at three sets of 8–12 repetitions at an intensity of 75-85% of 1 rep max. Each 
week, weight will progressively increase by 5–10% as needed due to training adaptation. For all 
exercises, the participants will be instructed to perform each repetition in a slow, controlled manner, 
with a rest of 1-2 min between sets. The participants will wear heart rate monitors (Fitbit Alta HR, 
Boston, MA) during each training session to provide visual feedback of their individualized target heart 
rate. Fitbit monitors will be distributed to subjects at each training session. Compliance with the 
training: A research assistant will be present to supervise all the training sessions for compliance and 
correct technique execution. Exercise will be carefully documented through attendance at the training 
sessions. Subjects will be permitted to choose the day and time slot that works best for them. If a 
subject misses their session, they will be required to make up for it that same week. Subjects will be 
permitted to miss 4 sessions total during the 8-week intervention. (see COVID protocols in Subject 
Safety) 
Control group protocol: Controls will be instructed to maintain their weight throughout the trial, and not to 
change eating or physical activity habits. Controls will visit the research center at the same frequency as the 
treatment groups (for outcome measurements) to control for investigator-interaction bias between groups. 
Controls will be offered free weight loss diet counseling (4 sessions) at the conclusion of the study by Kelsey 
Gabel, PhD., RD. 
 
Weekly check-in: Weekly check-in calls will be done with all participants regardless of group at a 
prespecified time weekly via either zoom or telephone based on the participant preference. This 
appointment time will remain the same throughout the 10 weeks. During this call the study coordinator will 
address possible issues with compliance, difficulty with the intervention, and complete the adverse events 
questionnaire verbally. Time stamped weigh in photos and adherence logs will also be requested at this 
appointment. Further, dietary counseling to support the participant will be included in each call by a 
registered dietitian (Kelsey Gabel, PhD, RD). Diet counseling will not include weight loss counseling, but 
general lifestyle improvement so as can be also given to the control group for weight maintenance. All 
counseling will be based off of recommendations from the Academy of Nutrition and Dietetics, The 
American Heart Association, and Healthy People 2020. Topics will include: 
 
• 
Increasing fruit and vegetable intake 
• 
Reading food labels 
• 
Water intake 
• 
Lean protein 
• 
Healthy fats 
• 
Whole grains 
• 
A balanced plate 
Choices for eating out 

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Subject compensation. No compensation or parking reimbursement is offered for trial completion. 
Participants will be able to have access to all data received from the study. In addition, controls will receive 
4 free diet counseling sessions at the conclusion of the study. 
Summary of intervention groups and key outcome measures 
 

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Study activities 
 
Study activities 
Baseline 
Intervention (8 weeks) 
Screen 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Informed consent 
• 
Screening/ Alcohol 
questionnaire 
• 

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Body weight 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
Waist circumference 
• 
• 
• 
Diet adherence 
• 
• 
• 
• 
• 
• 
• 
• 
• 
Fat mass (BIA) 
• 
• 
• 
• 
• 
• 
• 
• 
• 
Blood pressure/heart rate 
• 
• 
• 
• 
• 
• 
• 
• 
• 
DXA 
• 
Blood draw 
• 
• 
• 
• 
Activity monitor (7-d) 
• 
• 
Food record 
• 
• 
• 
Sleep questionnaires 
• 
• 
• 
Adverse events survey 
• 
• 
• 
• 
• 
• 
• 
• 
• 
NeuroTrax Cognition 
• 
• 
• 
Quality of life/mood 
• 
• 
• 
 
4.0 Data analysis 
Data will be analyzed by SPSS software (SPSS v24).  
5.0 Statistical considerations 
All continuous variables will be examined for distributions and the presence of outliers. Variables that are 
not normally distributed will be transformed and if normality cannot be achieved, will be analyzed using 
non-parametric tests. Standardized descriptive statistics including measures of means, median, standard 
deviations, ranges, and standard errors for continuous variables within each group will be calculated to 
describe the groups at fixed time points. Differences between groups at baseline will be assessed by a one- 
way ANOVA. A linear mixed model will be used to assess time, diet, and time × diet effects for each 
outcome. This model will provide unbiased estimates of time and treatment effects under a missing- at- 
random assumption. Time will not be assumed to be linear in the model. This strategy will allow for 
estimation of time and diet effects (and their interaction) without imposing a linear time trend. Relations 
between continuous variables will be assessed by Pearson’s or Spearman’s correlation coefficients as 
appropriate. Data will be analyzed using SPSS software (SPSS, Chicago, IL). 
 
6.0 References 
 
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3. 
Willmann C, Brockmann K, Wagner R, et al. Insulin sensitivity predicts cognitive decline in individuals with 
prediabetes. BMJ Open Diabetes Res Care 2020;8(2). DOI: 10.1136/bmjdrc-2020-001741. 
4. 
Ekblad LL, Rinne JO, Puukka P, et al. Insulin Resistance Predicts Cognitive Decline: An 11-Year Follow-up 
of a Nationally Representative Adult Population Sample. Diabetes Care 2017;40(6):751-758. DOI: 
10.2337/dc16-2001. 
5. 
United Nations DoEaSA, Population Division. World Population Ageing 2019. Highlights 
2019;(ST/ESA/SER.A/430). 
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de Cabo R, Mattson MP. Effects of Intermittent Fasting on Health, Aging, and Disease. N Engl J Med 
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8. 
Harvard University Health Blog. Intermittent fasting - Surprising update. 
(https://www.health.harvard.edu/blog/intermittent-fasting-surprising-update-2018062914156). 
9. 
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Associated Press. In a 24/7 food culture, periodic fasting gains followers. 
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