Diabetes, Obesity
Conditions
Brief summary
The aims of this proposal are to compare the effects of 4-h versus 6-h time restricted feeding (TRF) on body weight and metabolic disease risk factors in adults with obesity. To test the study objectives, a 10-week randomized, controlled, parallel-arm trial, divided into 2 consecutive periods: (1) 2-week baseline period; and (2) 8-week TRF weight loss period, will be implemented. Obese subjects will be randomized to 1 of 3 groups: (1) 4-h TRF, (2) 6-h TRF, or a no-intervention control group. This study will be the first randomized controlled trial to compare 4-h versus 6-h TRF.
Detailed description
Modest weight loss of 5-10% is sufficient to reduce metabolic disease risk in obese individuals. The first line of therapy prescribed for weight loss is daily calorie restriction (CR; 25% restriction every day). However, adherence to CR greatly diminishes after 4-6 weeks, due to subject frustration with constantly having to count calories and never being able to eat freely. In light of these issues with CR, another approach that limits timing of food intake, instead of number of calories consumed, has been developed. This strategy is termed time restricted feeding (TRF), and involves confining the period of food intake to 8 h/d (10 am to 6 pm) without calorie counting. Preliminary findings of 8-h TRF demonstrate modest weight loss and blood pressure reductions after 12 weeks. What remains unknown however, is whether shorter feeding windows during TRF (such as 4-h or 6-h feeding windows) can produce even greater weight loss in obese adults. Also of interest, is the impact of these shorter feeding windows on metabolic disease risk indicators (such as plasma lipids, blood pressure, and insulin resistance, inflammation and oxidative stress). Accordingly, the aims of this proposal are: AIM 1: To compare the effects of 4-h versus 6-h time restricted feeding (TRF) on body weight in adults with obesity; AIM 2: To compare the effects of 4-h versus 6-h TRF on metabolic disease risk factors in adults with obesity. To test the study objectives, a 10-week randomized, controlled, parallel-arm trial, divided into 2 consecutive periods: (1) 2-week baseline period; and (2) 8-week TRF weight loss period, will be implemented. Obese subjects will be randomized to 1 of 3 groups: (1) 4-h TRF, (2) 6-h TRF, or a no-intervention control group. This study will be the first randomized controlled trial to compare 4-h versus 6-h TRF on body weight and metabolic disease risk markers.
Interventions
BEHAVIORALTime restricted feeding
TRF subjects will consume food ad libitum during the feeding window (4-h or 6-h window), and refrain from eating during the fasting window (20-h or 18-h window)
Sponsors
University of Illinois at Chicago
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
* Male or female; * body mass index (BMI) between 30.0 and 49.9 kg/m2; * age between 18 and 65 years; sedentary (light exercise less than 1 h per week) or moderately active (moderate exercise 1 to 2 h per week); * weight stable for \>3 months prior to the beginning of the study (gain or loss \<4 kg); * able to give written informed consent
Exclusion criteria
* Smoker; diabetic; * taking weight loss medications; * taking medication that requires eating food before (or with) the medication; history of eating disorders; * night-shift workers; * perimenopausal; * pregnant women
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change from baseline to week 8 in body weight | Measured at week 1 and 8 | Measured by an electronic scale |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change from baseline to week 8 in Insulin resistance | Measured at week 1 and 8 | Measured as HOMA-IR |
| Change from baseline to week 8 in Fasting glucose | Measured at week 1 and 8 | Measured with a hexokinase reagent kit |
| Change from baseline to week 8 in Fasting insulin | Measured at week 1 and 8 | Measured as total immunoreactive insulin |
| Change from baseline to week 8 in Blood pressure | Measured at week 1 and 8 | Measured by a blood pressure cuff |
| Change from baseline to week 8 in adverse events | Measured weekly from baseline to week 8 | Measured by questionnaire |
| Change from baseline to week 8 in plasma lipids | Measured at week 1 and 8 | Measured by outside lab (Medstart, IN) |
| Change from baseline to week 8 in heart rate | Measured at week 1 and 8 | Measured by a blood pressure cuff |
| Change from baseline to week 8 in inflammatory markers (TNF-a, IL-6) | Measured at week 1 and 8 | Measured by ELISA |
| Change from baseline to week 8 in body composition | Measured at week 1 and 8 | Measured by DXA |
| Change from baseline to week 8 in calorie and macronutrient intake | Measured at week 1 and 8 | Measured by food record |
| Change from baseline to week 8 in physical activity (steps/d) | Measured at week 1 and 8 | Measured by activity monitor |
| Change from baseline to week 8 in diet adherence | Measured weekly from baseline to week 8 | Measured by a questionnaire |
| Change from baseline to week 8 in sleep quality | Measured at week 1 and 8 | Measured by a questionnaire |
| Change from baseline to week 8 in insomnia severity | Measured at week 1 and 8 | Measured by a questionnaire |
| Change from baseline to week 8 in risk of sleep apnea | Measured at week 1 and 8 | Measured by a questionnaire |
| Change from baseline to week 8 in sex steroid levels (estrogen, androgens, sex hormone binding globulin) | Measured at week 1 and 8 | Measured by a ELISA |
| Change from baseline to week 8 in oxidative stress (8-isoprostane) | Measured at week 1 and 8 | Measured by ELISA |
Countries
United States
Outcome results
None listed