An interventional study of Early dinner and Late Dinner in Healthy, sponsored by Johns Hopkins University. Completed at 1 site in United States. Open to participants aged 18 Years to 30 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-02-04.
Sponsored by Johns Hopkins University · Not applicable, Interventional, and Basic science
This study examines the acute impact of eating an "early" versus "late" dinner. "Early" and "late" will be customized to individuals based on the individuals' own circadian rhythms. Healthy adults will have the adults' circadian rhythm assessed by measuring the adults' dim light melatonin onset (DLMO). Based on the timing of DLMO, participants will be randomized to eating dinner before DLMO or after DLMO. The investigators will also compare the effects of delaying sleep relative to dinner time. Participants will eat meals in the laboratory and have serial plasma samples collected to examine profiles of free fatty acids, glucose, insulin, triglycerides, and oxidation of dietary fat.
Obesity is a worldwide health problem. Recent studies suggest that the timing of meals may be critically important for weight control and cardiovascular health. Consuming calories later in the day is associated with greater risks of obesity, metabolic syndrome, and cardiovascular disease. Interventional diet studies also show more effective weight loss with early, rather than later eating. The investigators conducted a randomized crossover study comparing the metabolic effect of a "routine" dinner (RD,18:00) with that of an isocaloric "late" dinner (LD, 22:00) in 20 healthy volunteers. The investigators recently published results of this study, which the investigators now refer to as "Dinner Time 1". Relative to RD, LD increased post-dinner glucose peak by \~18% and lowered palmitate oxidation by \~10%. However, it is still unclear whether LD-induced impaired metabolic dysfunction is caused by eating at the "wrong" time relative to the body's central circadian clock, or it is caused by eating too close to bedtime, when sleep reduces metabolic demands.
To address this question, the investigators are now enlarging the scope of the present study, which the investigators now refer to as "Dinner Time 2". In Dinner Time 2, the investigators will examine the impacts of early dinner, late dinner, and the impact of delaying sleep after late dinner. The investigators will compare (1) the impact of early dinner time with later dinner time relative to DLMO with a routine sleep time; and (2) the impact of routine bedtime with late bedtime with a fixed late dinner time.
The investigators will examine the nocturnal and next-morning metabolic profile in a 3-arm randomized crossover study of healthy volunteers:
Arm 1: Early Dinner (dinner at DLMO-3, sleep at DLMO+2) Arm 2: Late Dinner (dinner at DLMO+1, sleep at DLMO+2) Arm 3: Late Dinner/Late Sleep (dinner at DLMO+1, sleep at DLMO+6)
The investigators will use serial blood sampling to assess the metabolic response to meals, and use an ingested stable isotope [(2H31)palmitate] tracer to calculate the oxidation of dietary lipid eaten at the different times.
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Participants will be served dinner and a stable isotope of palmitate to measure fat oxidation, at an early dinner time (DLMO-3h) followed by a sleep study (DLMO+2h). This arm will cross-over to the other 2 arms in random order.
Behavioral: Early dinner · Behavioral: Late Dinner · Behavioral: Late Dinner + Late Sleep
Participants will be served dinner and a stable isotope of palmitate to measure fat oxidation, at a late dinner time (DLMO+1h) followed by a sleep study (DLMO+2h). This arm will cross-over to the other 2 arms in random order.
Behavioral: Early dinner · Behavioral: Late Dinner · Behavioral: Late Dinner + Late Sleep
Participants will be served dinner and a stable isotope of palmitate to measure fat oxidation, at a late dinner time (DLMO+1h) followed by delayed bedtime (DLMO+6h). This arm will cross-over to the other 2 arms in random order.
Behavioral: Early dinner · Behavioral: Late Dinner · Behavioral: Late Dinner + Late Sleep
Dinner at DLMO-3, sleep at DLMO+2
Dinner at DLMO+1, sleep at DLMO+2
Dinner at DLMO+1, sleep at DLMO+6
Change in Glucose (mg/dl)
Serial blood samples taken during visit, 25 samples taken over 25 hours (One every hour) per visit.
Time frame: Baseline, 4 weeks and 8 weeks
Change in Free Fatty Acids (FFA, mmol/L)
Serial blood samples taken during visit, 25 samples taken over 25 hours (One every hour) per visit.
Time frame: Baseline, 4 weeks and 8 weeks
Change in Insulin (mcU/ml)
Serial blood samples taken during visit, 25 samples taken over 25 hours (One every hour) per visit.
Time frame: Baseline, 4 weeks and 8 weeks
Change in Triglycerides (mg/dl)
Serial blood samples taken during visit, 25 samples taken over 25 hours (One every hour) per visit.
Time frame: Baseline, 4 weeks and 8 weeks
Change in Oxidation of palmitate (percent of isotope enrichment)
Serial blood samples taken during visit (14 samples per visit).
Time frame: Baseline, 4 weeks and 8 weeks
Change in melatonin [Dim light melatonin onset (DLMO)]
Serial saliva samples taken during visit, 14 samples taken over 7 hours (one sample every 30 minutes) to access change in melatonin levels (pg/ml) over 7 hours.
Time frame: At 2 weeks prior to baseline (samples drawn every 30 minutes, up to 7 hours)
Sleep architecture
Sleep stage distribution by EEG during each of the 3 sleep studies.
Time frame: Baseline, 4 weeks and 8 weeks
Plan to share: Yes — We will provide raw data (without identifying information) to journals or other researchers upon request.
Supporting information: Study protocol, Sap, Icf
This study is completed, as verified in Feb 2026. You cannot join it, but the record below documents what was studied.
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