Time Restricted Eating for Weight Management

A 12-month randomized, controlled, parallel-arm trial, divided into 2 consecutive periods: (1) 6-month weight loss period; and (2) 6-month weight maintenance, will be implemented. Adults with obesity will be randomized to 1 of 3 groups: (1) 8h-TRE, ad libitum food intake from 12pm to 8 pm, fasting from 8 pm to 12 pm daily, (2) CR, 25% energy restriction every day; or 3) control, ad libitum food intake daily, eating within more than 10 hours per day.

Study Overview

• Status: Completed
• Conditions: Obesity
• Intervention / Treatment: Other: 8-hour Time restricted eating; Other: Calorie restriction

Detailed Description

Time restricted eating (TRE) has become a popular weight loss regimen. The sudden rise in popularity of TRE is mostly likely due to is its sheer simplicity, and the fact that it does not require individuals to count calories in order to lose weight. Participants are simply asked to consume all food within a specified time frame and fast with energy free beverages for the remaining hours of the day. Evidence shows that when people with obesity limit their eating window to 6 to 8 hours per day, they naturally reduce energy intake by 350-500 calories. From a clinical standpoint, these findings are paramount. One of the main reasons for subject attrition with traditional dieting, i.e. daily calorie restriction (CR), is frustration with having to count calories every day. TRE regimens are able to side-step this requirement by allowing participants to simply "watch the clock" instead of monitoring calories, while still producing significant weight loss and metabolic health improvements. This feature of TRE has the potential to improve long-term adherence to the diet, and in turn produce lasting weight control in adults with obesity.

Accordingly, we conducted a one-year, randomized, controlled trial to compare the effects of late TRE (eating all food between 12:00 pm to 8:00 pm, without calorie counting), versus CR (25% energy restriction daily), and a control group eating over a period of 10 or more hours, on body weight and metabolic risk factors in a diverse group of American adults with obesity. We hypothesized that the TRE group would achieve greater weight loss, and experience more pronounced improvements in insulin sensitivity during the 6-month weight loss phase, compared to CR and control participants. We also hypothesized that the TRE group would better maintain their weight loss and sustain their improvements in insulin sensitivity during the 6-month weight maintenance phase, when compared to the CR and control participants.

• Study Type: Interventional
• Enrollment (Actual): 90
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Illinois
    • Chicago, Illinois, United States, 60612
      • University of Illinois Chicago

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion criteria:

• Age between 18 to 65 years old
• BMI between 30 and 50 kg/m2
• Sedentary or lightly active (<60 minutes/week of light activity for the 3 months prior to the study)

Exclusion criteria:

• • Type 1 DM or Type 2 DM
• History of eating disorders (anorexia, bulimia, or binge eating disorder)
• 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 perimenopausal or have an irregular menstrual cycle (menses that does not appear every 27-32 days)
• Are eating within less than a 10-hour window at baseline
• Are pregnant, or trying to become pregnant
• Are night shift workers
• Are smokers

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 8-hour Time restricted eating; Ad libitum food intake from 12-8 pm every day Fasting from 8-12 pm every day (16-h fast)	Other: 8-hour Time restricted eating; Ad libitum food intake from 12-8 pm every day Fasting from 8-12 pm every day (16-h fast)
Experimental: Calorie restriction; 25% energy restriction every day	Other: Calorie restriction; 25% energy restriction every day
No Intervention: Control; Usual diet, Ad libitum intake, eating within >10 hours per day

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in body weight	Measured by an electronic scale	Measured at month 0, 6 and 12

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in fat mass, lean mass, visceral fat mass	Measured by DXA	Measured at month 0, 6 and 12
Change in bone mineral density	Measured by DXA	Measured at month 0, 6 and 12
Change in waist circumference	Measured by a measuring tape	Measured at month 0, 6 and 12
Change in Insulin resistance	Measured by HOMA-IR	Measured at month 0, 6 and 12
Change in Insulin sensitivity	Measured by QUICKI	Measured at month 0, 6 and 12
Change in Fasting glucose	Measured by a commercial lab (Medstar, IL)	Measured at month 0, 6 and 12
Change in HbA1c	Measured by a commercial lab (Medstar, IL)	Measured at month 0, 6 and 12
Change in Fasting insulin	Measured by a commercial lab (Medstar, IL)	Measured at month 0, 6 and 12
Change in Blood pressure	Measured by a blood pressure cuff	Measured at month 0, 6 and 12
Change in Heart rate	Measured by a blood pressure cuff	Measured at month 0, 6 and 12
Change in Plasma lipids (LDL cholesterol, HDL cholesterol, triglycerides)	Measured by a commercial lab (Medstar, IL)	Measured at month 0, 6 and 12
Change in inflammatory markers (TNF-apha, IL-6, IL-10, IL-B, hs-CRP)	Measured by ELISA	Measured at month 0, 6 and 12
Change in oxidative stress	Measured by ELISA	Measured at month 0, 6 and 12
Change in energy and nutrient intake	Measured by 7-day food record	Measured at month 0, 6 and 12
Change in physical activity (steps/d)	Measured by pedometer	Measured at month 0, 6 and 12
Change in the daily eating window	Measured by questionnaire (assesses the time the participant started and stopped eating each day)	Measured at month 0, 6 and 12
Change in sleep quality	Measured by Pittsburgh Sleep Quality Index (PSQI), total score of 0-21. A PSQI total score greater than 5 indicates poor sleep quality.	Measured at month 0, 6 and 12
Change in insomnia severity	Measured by Insomnia Severity Index (ISI), total score of 0-28. The total score for the ISI is interpreted as follows: no clinically significant insomnia (0-7), sub-threshold insomnia (8-14), moderate severity insomnia (15-21), and severe insomnia (22-28).	Measured at month 0, 6 and 12
Change in risk of sleep apnea	Measured by Berlin Questionnaire, measures the presence or absence of sleep apnea	Measured at month 0, 6 and 12
Adverse events	Measured by questionnaire	Measured at month 0, 6 and 12
Change in appetite	Measured by Visual analog scale (VAS). Scored from 0-100. Higher score means higher appetite.	Measured at month 0, 6 and 12
Change in eating disorder symptoms	Measured by Multifactorial Assessment of Eating Disorders Symptoms (MAEDS), total score of 0-100, Higher scores mean worse outcome.	Measured at month 0, 6 and 12
Change in mood	Measured by Beck Depression Inventory II (BDI-II) 25: total score 0-100. Higher scores mean worse outcome. Also measured by the Profile of Mood States (POMS)total score 0-100. Higher scores mean worse outcome.	Measured at month 0, 6 and 12
Change in quality of life	Measured by the Short Form Survey (SF-36): total score 0-100. Higher scores mean worse outcome.	Measured at month 0, 6 and 12
Change in estradiol levels (ng/ml)	Measured by ELISA	Measured at month 0, 6 and 12
Change in testosterone levels (ng/ml)	Measured by ELISA	Measured at month 0, 6 and 12
Change in dehydroepiandrosterone (DHEA) levels (ng/ml)	Measured by ELISA	Measured at month 0, 6 and 12
Change in sex hormone binding globulin (SHBG) levels (ng/ml)	Measured by ELISA	Measured at month 0, 6 and 12
Change in progesterone levels (ng/ml)	Measured by ELISA	Measured at month 0, 6 and 12

Collaborators and Investigators

• Sponsor: University of Illinois at Chicago
• Investigators: Principal Investigator: Krista Varady, PhD, University of Illinois Chicago

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2021
• Primary Completion (Actual): February 1, 2025
• Study Completion (Actual): February 1, 2025

Study Registration Dates

• First Submitted: December 28, 2020
• First Submitted That Met QC Criteria: December 30, 2020
• First Posted (Actual): January 5, 2021

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: February 21, 2025
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: 2020-1512

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No