TIMED EATING: Comparison of Time-Restricted Feeding Versus Grazing

Sponsor

Pennington Biomedical Research Center (Other)

Overall Status

Completed

CT.gov ID

NCT01895179

Collaborator

(none)

Enrollment

Location

Arms

Duration (Months)

0.2

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

The purpose of this pilot study is to find out what eating meals in a short time period early in the day (time-restricted feeding) versus eating meals spread out during the day (grazing) does to the body's ability to control blood sugar and to the health of its blood vessels.

The investigators hypothesize that time-restricted feeding will be more effective at improving glucose tolerance and vascular condition (inflammation and micro- and macro-vascular function) than grazing.

Condition or Disease	Intervention/Treatment	Phase
Prediabetes Insulin Resistance Vascular Diseases	Other: Time-Restricted Feeding Other: Grazing	N/A

Detailed Description

Each participant will eat according to one of the two eating schedules (grazing or time-restricted feeding) for 5 weeks, have a 7-week washout period, and then eat according to the other eating schedule for 5 weeks. Measurements of glucose homeostasis and vascular condition will be performed before and after a participant follows each eating schedule.

Study Design

Study Type:

Interventional

Actual Enrollment :

8 participants

Allocation:

Randomized

Intervention Model:

Crossover Assignment

Masking:

None (Open Label)

Primary Purpose:

Prevention

Official Title:

Time-Restricted Feeding to Improve Glucose Tolerance and Vascular Condition

Study Start Date :

Jul 1, 2013

Actual Primary Completion Date :

Nov 1, 2017

Actual Study Completion Date :

Nov 1, 2017

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Time-Restricted Feeding (early in the day eating) Participants will consume all meals early in the day and within a 6-hour window.	Other: Time-Restricted Feeding Time-restricted feeding is a variant of intermittent fasting that involves eating all of one's calories within a few hours each day (typically 4-9 hours), followed by a daily fast of 15-20 hours.
Placebo Comparator: Grazing Participants will eat meals spread out over the course of the day.	Other: Grazing Grazing involves eating meals spread out over the course of the day.

Arm

Intervention/Treatment

Experimental: Time-Restricted Feeding (early in the day eating)

Participants will consume all meals early in the day and within a 6-hour window.

Other: Time-Restricted Feeding

Time-restricted feeding is a variant of intermittent fasting that involves eating all of one's calories within a few hours each day (typically 4-9 hours), followed by a daily fast of 15-20 hours.

Placebo Comparator: Grazing

Participants will eat meals spread out over the course of the day.

Other: Grazing

Grazing involves eating meals spread out over the course of the day.

Outcome Measures

Primary Outcome Measures

Change in Glucose Tolerance [Before and after 5 weeks on each feeding schedule]
Glucose tolerance and indices of glucose homeostasis will be determined using an Oral Glucose Tolerance Test (OGTT).

Secondary Outcome Measures

Change in Vascular Function [Before and after 5 weeks on each feeding schedule]
Macro- and micro-vascular function will be assessed by Radial Artery Applanation Tonometry and by Orthogonal Polarization Spectroscopy. The endpoints measured by these two tests include aortic blood pressure, arterial stiffness, capillary density, and red blood cell velocity.
Change in Inflammation and Metabolic Markers [Before and after 5 weeks on each feeding schedule]
Serum markers of inflammation, such as C-Reactive Protein (CRP) and inflammatory cytokines, and of metabolic processes will be measured (composite measure).

Eligibility Criteria

Criteria

Ages Eligible for Study:

35 Years to 70 Years

Sexes Eligible for Study:

Male

Accepts Healthy Volunteers:

Yes

Inclusion Criteria:

Are male
Overweight: Have a body mass index between 25 and 50 kg/m^2 inclusive (a number calculated from height and weight)
Are 35-70 years of age
Have a hemoglobin A1C between 5.5 - 6.4% or prior medical indication of prediabetes
Have a blood sugar level between 140 and 199 mg/dL two hours after drinking a sugary solution (OGTT)
Have been eating dinner at least 8.5 hours after eating breakfast at least 90% of the time during the past year
Have not fasted (go for a day without any food) more than 12 days total during the past year
Be willing to eat most meals at Pennington Biomedical and/or under supervision
Not eat any food other than that served by Pennington Biomedical
Not drink any alcohol, juice, or other beverages that have calories other than what is served by Pennington Biomedical
Keep water and no-calorie drinks like tea or diet soda the same during both of the timed eating periods
Be willing to eat your meals according to the fixed schedules

Exclusion Criteria:

Have diabetes or are on anti-diabetes medication
Have evidence of cardiovascular disease
Suffer from significant cardiovascular, renal (kidney), cardiac (heart), liver, lung or nervous system disease
Evidence of significant gastrointestinal issues or surgery that impacts nutrient absorption
Regularly use medications such as steroids, beta blockers, and adrenergic-stimulating agents
Are on any regular medicine that has not had the same dose for 1 month or longer
Have a clinically significant abnormality as measured by a blood test
Regularly drink alcohol (more than 2 servings per day)
Have to do any kind of heavy physical activity
Currently perform overnight shift work more than one day a week
Are not able to eat only the food served to you by Pennington Biomedical, while in the study
Are not able to stop drinking alcohol or other drinks with calories (e.g., soda, juice) other than what is served to you by Pennington Biomedical, while in the study