Early vs Late Dinner for Obesity

(DTOP Trial)

Recruiting at 1 trial location

Overseen By Jonathan Jun, MD

Age: 18 - 65

Sex: Any

Trial Phase: Academic

Sponsor: Johns Hopkins University

Must not be taking: Diabetes medications, Psychiatric medications

Disqualifiers: Sleep disorders, Diabetes, Cardiovascular disease, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 3

Duration: 8 weeks

32 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how dinner timing affects weight and metabolism. Researchers are particularly interested in whether eating earlier or later in the evening influences body weight and metabolic health. Participants will try both an early dinner (known as Time-Restricted Eating or Early Time-Restricted Feeding) and a late dinner to observe how these changes impact fat processing in the body. Ideal candidates are healthy adults with a normal weight, no sleep disorders, and no significant recent weight changes. As an unphased trial, this study allows participants to contribute to groundbreaking research on diet and metabolism.

Will I have to stop taking my current medications?

Yes, you may need to stop taking certain medications. The trial excludes participants taking prescription medications or drugs that may influence metabolism, such as diet/weight-loss medication, asthma medication, blood pressure medication, psychiatric medications, and others. It's best to discuss your specific medications with the study team.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research has shown that having dinner earlier can safely and effectively aid weight loss and improve overall health in people with obesity. Time-restricted eating (TRE), which involves consuming meals earlier in the day, has helped individuals lose 1% to 4% of their body weight over several weeks. It also boosts fat burning and improves insulin levels, aiding in blood sugar control.

In contrast, studies suggest that eating dinner late might not be as beneficial. Late dinners can impair sugar processing during sleep and may reduce fat burning, increasing hunger and potentially leading to weight gain and other health issues over time.

While both early and late dinner timings are generally safe, early dinners have demonstrated more positive effects on metabolism and weight management. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about this trial because it explores how the timing of dinner can influence obesity, a fresh approach compared to traditional methods like diet changes or medication. This study looks at how eating earlier or later affects fat burning in the body, using a special tracer to track fat oxidation. By understanding these effects, scientists hope to uncover new strategies for managing obesity that are simple and lifestyle-based, potentially offering a more natural and sustainable option for weight control.

What evidence suggests that this trial's treatments could be effective for obesity?

This trial will compare the effects of eating dinner at different times on obesity. Research has shown that eating dinner earlier can aid weight loss and improve overall health. Studies have found that people who eat dinner early can lose 1% to 4% of their body weight in just a few weeks. This habit also helps burn fat and lower blood pressure. Conversely, eating dinner late is linked to poorer metabolism, such as higher blood sugar levels and reduced fat burning at night. Late dinners can also increase hunger and the risk of weight gain. Overall, aligning dinner with the body's natural schedule seems to support better health. Participants in this trial will follow both early and late dinner schedules to assess these effects. ^{4 6 7 8 9}

Who Is on the Research Team?

Jonathan Jun, MD

Principal Investigator

Johns Hopkins University

Stephanie T Chung, MBBS

Principal Investigator

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Are You a Good Fit for This Trial?

Adults aged 18-50 with obesity and prediabetes (BMI ≥30 kg/m2) or healthy subjects with a BMI of 18-24.9 can join this study. Participants must understand the procedures, not have metabolic disorders, gastrointestinal surgeries, severe sleep issues, or be on certain medications that affect metabolism.

Inclusion Criteria

I am 18-50 years old, overweight, and have prediabetes.

I am a healthy adult aged 18-50 with a BMI between 18-24.9.

All participants must be able to understand study procedures and to comply with the procedures for the entire length of the study.

Exclusion Criteria

You are currently in a program to lose weight.

I am taking medication that can affect my body's daily rhythms.

I have a condition that could block my digestive system.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Circadian Phenotyping

Participants undergo circadian phenotyping with assessment of DLMO, core body temperature profile, and wrist actigraphy

1 week

1 visit (in-person)

Treatment

Participants are randomized to early or late dinner conditions in a 24-hour metabolic chamber protocol, with a crossover design and a 3- to 4-week washout period

8 weeks

2 visits (in-person)

Follow-up

Participants are monitored for metabolic outcomes such as glucose and fat oxidation levels

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Early Dinner
• Early Dinner tracer
• Late Dinner
• Late Dinner tracer

Trial Overview The trial is testing how eating dinner early versus late affects weight and metabolism in relation to our body's natural clock. It uses precise methods to measure the body's circadian rhythm and its impact on health when aligning meal times.

How Is the Trial Designed?

Group I: Late Dinner First Experimental Treatment 4 Interventions

Participants will be served dinner and a stable isotope of oral \[2H31\] palmitate to measure fat oxidation, at a late dinner time (after DLMO). This arm will then cross-over to Early Dinner as the second metabolic visit.

Group II: Early Dinner First Experimental Treatment 4 Interventions

Participants will be served dinner and a stable isotope of oral \[2H31\] palmitate to measure fat oxidation, at an early dinner time (before DLMO). This arm will then cross-over to Late Dinner as the second metabolic visit.

Who Is Running the Clinical Trial?

Johns Hopkins University

Lead Sponsor

Trials

2,366

Recruited

15,160,000+

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Collaborator

Trials

2,513

Recruited

4,366,000+

Published Research Related to This Trial

In a study of 81 adults with obesity, those with a morning chronotype (MC) spent significantly more time eating lunch and dinner compared to evening chronotype (EC) individuals, who ate faster.

The faster eating speed of EC individuals may contribute to their higher risk of obesity-related cardiometabolic diseases, highlighting the importance of chronotype in dietary habits.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

How Fast Do "Owls" and "Larks" Eat? Verde, L., Docimo, A., Chirico, G., et al.[2023]

In a study involving 11 sedentary men with overweight/obesity, time-restricted feeding (TRF) for 8 hours per day showed a tendency to lower total 24-hour glucose levels compared to extended feeding (EXF) for 15 hours, with significant improvements in nocturnal glucose control.

Participants reported positive attitudes towards TRF, noting improved well-being, although they identified challenges such as work schedules and social commitments that could hinder adherence.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A Delayed Morning and Earlier Evening Time-Restricted Feeding Protocol for Improving Glycemic Control and Dietary Adherence in Men with Overweight/Obesity: A Randomized Controlled Trial. Parr, EB., Devlin, BL., Radford, BE., et al.[2020]

About 64.4% of US adults reported eating late in the evening, and most of these individuals consumed significantly more calories than those who did not, with an increase of at least 268 kcal depending on the specific eating pattern.

While late evening eating generally led to higher energy intake, it did not significantly improve overall diet quality as measured by the Healthy Eating Index, except for those who primarily consumed fruits in the evening.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Late Evening Eating Patterns among US Adults Vary in Their Associations With, and Impact on, Energy Intake and Diet Quality: Evidence from What We Eat in America, National Health and Nutrition Examination Survey 2013-2016. Sebastian, RS., Wilkinson Enns, C., Goldman, JD., et al.[2022]

In a study of 44 adults, those with an early chronotype (morning preference) had a lower body mass index (BMI) and reported smaller appetites compared to those with a late chronotype (evening preference).

Participants who ate earlier in the day had a reduced desire for high-fat foods and felt fuller after meals, suggesting that early meal timing and chronotype can influence appetite and food preferences.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Impact of Meal Timing and Chronotype on Food Reward and Appetite Control in Young Adults. Beaulieu, K., Oustric, P., Alkahtani, S., et al.[2021]

Time-restricted eating (TRE) has shown promising therapeutic effects in rodent studies, particularly in relation to body weight and metabolic health, but results in humans are inconsistent due to varying study designs and populations.

This review highlights the need for more standardized research on TRE in humans to better understand its effects and interactions with circadian biology, as well as to identify gaps in current knowledge for future studies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Complex physiology and clinical implications of time-restricted eating. Petersen, MC., Gallop, MR., Flores Ramos, S., et al.[2023]

In a 12-week study involving 23 obese adults, time-restricted feeding (TRF) with an 8-hour eating window was found to be safe, as there were no significant changes in self-reported adverse events or disordered eating patterns.

The study suggests that TRF can effectively support weight loss in obese individuals without negatively impacting their health or body image perception.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety of 8-h time restricted feeding in adults with obesity. Gabel, K., Hoddy, KK., Varady, KA.[2019]

In a study involving 99 participants over three months, time-restricted eating (TRE) did not show significant differences in obesity-related outcomes based on the timing of food intake, whether early, medium, or late.

Participants who started eating earlier had a longer eating duration but the late eaters had a longer fasting period, suggesting that the timing of food intake may not be as crucial as previously thought, and further research is needed to clarify these findings.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Early or Delayed Onset of Food Intake in Time-Restricted Eating: Associations with Markers of Obesity in a Secondary Analysis of Two Pilot Studies. Kesztyüs, D., Cermak, P., Kesztyüs, T., et al.[2023]

In an 8-week pilot study involving 78 participants with obesity, those following a 14-hour time-restricted eating (TRE) schedule lost an average of 8.5% of their body weight, which was statistically significant compared to a 12-hour TRE group that lost 7.1%.

The 14:10 TRE group also experienced a significant reduction in fasting blood glucose levels by 7.6 mg/dl, indicating potential metabolic benefits, especially for those with elevated blood glucose at baseline.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of time restricted eating on body weight and fasting glucose in participants with obesity: results of a randomized, controlled, virtual clinical trial. Peeke, PM., Greenway, FL., Billes, SK., et al.[2021]

In a study involving overweight and obese young adults, both early time-restricted eating (eTRE) and late time-restricted eating (lTRE) resulted in similar weight loss after 8 weeks compared to a control group.

eTRE was more effective than lTRE in improving several metabolic health markers, including reducing systolic blood pressure, glucose levels, fasting insulin, insulin resistance, and thyroid axis activity, while lTRE only reduced leptin levels.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Randomized controlled trial for time-restricted eating in overweight and obese young adults. Zhang, LM., Liu, Z., Wang, JQ., et al.[2022]

A randomized controlled trial found that late eating significantly increased hunger and altered appetite-regulating hormones, leading to a higher ghrelin-to-leptin ratio, which can promote weight gain.

Late eating also decreased energy expenditure and core body temperature, while affecting adipose tissue gene expression in ways that may increase fat storage and decrease fat breakdown, suggesting multiple mechanisms that contribute to obesity risk.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Late isocaloric eating increases hunger, decreases energy expenditure, and modifies metabolic pathways in adults with overweight and obesity. Vujović, N., Piron, MJ., Qian, J., et al.[2023]

In a study of 50 adults with overweight and obesity, participants successfully reduced their eating window from an average of 16 hours to about 12 hours over a 90-day time-restricted eating (TRE) intervention, leading to significant weight loss and reductions in waist circumference and blood pressure.

The TRE approach, which required no dietary counseling and was monitored through a smartphone app, showed a feasible and effective way to improve eating patterns and health outcomes in this population.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A Smartphone Intervention to Promote Time Restricted Eating Reduces Body Weight and Blood Pressure in Adults with Overweight and Obesity: A Pilot Study. Prasad, M., Fine, K., Gee, A., et al.[2021]

Individuals with a late chronotype (evening type) are more likely to be overweight or obese and have poorer metabolic health compared to those with an early chronotype (morning type), despite similar overall energy and macronutrient intakes.

Late chronotypes tend to consume more food during nighttime hours, which is associated with unhealthy eating behaviors and unfavorable dietary choices, contributing to their increased risk of obesity and metabolic issues.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Chronotype Differences in Body Composition, Dietary Intake and Eating Behavior Outcomes: A Scoping Systematic Review. van der Merwe, C., Münch, M., Kruger, R.[2023]

Citations

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Effectiveness of Early Time-Restricted Eating for Weight Loss ... In this randomized clinical trial, eTRE was more effective for losing weight and improving diastolic blood pressure and mood than eating over a window of 12 or ...

2. jamanetwork.com jamanetwork.com/journals/jamainternalmedicine/fullarticle/2794819

Effectiveness of Early Time-Restricted Eating for Weight ... Adults who adhere to TRE typically lose 1% to 4% of their body weight within several weeks. Further, TRE increases fat oxidation and can improve ...

3. sciencedirect.com sciencedirect.com/science/article/pii/S0261561425000950

Randomized Control Trials Early time-restricted eating with ... Early time-restricted eating with energy restriction has a better effect on body fat mass, diastolic blood pressure, metabolic age and fasting glucose

4. nature.com nature.com/articles/s41598-025-20502-y

The effects of time-restricted feeding on early vascular, liver ... Emerging evidence suggests that TRF, which extends nighttime fasting to over 12 h, may improve key cardiovascular health indicators. In animal ...

5. frontiersin.org frontiersin.org/journals/nutrition/articles/10.3389/fnut.2025.1664412/full

Effects of time-restricted eating on body composition and ... Our findings indicate that TRE significantly improves insulin levels in overweight and obese women, whereas no significant alterations were observed in blood ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC12479299/

Effects of time-restricted eating on body composition and ... Our findings indicate that TRE significantly improves insulin levels in overweight and obese women, whereas no significant alterations were ...

7. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC9877132/

Early Time-Restricted Eating Affects Weight, Metabolic ... Data are mixed on whether intermittent fasting improves weight loss and cardiometabolic health. Here, we analyzed the effects of time-restricted eating ...

8. sciencedirect.com sciencedirect.com/science/article/pii/S1550413123004540

Time-restricted eating: Watching the clock to treat obesity In participants with obesity, time-restricted eating results in 3%–5% weight loss over 2–12 months, versus controls. Reductions in body weight ...

9. nutritionandmetabolism.biomedcentral.com nutritionandmetabolism.biomedcentral.com/articles/10.1186/s12986-025-00984-3

per-protocol analysis of a 3-month randomized clinical trial Early Time-Restricted feeding reduces appetite and increases fat oxidation but does not affect energy expenditure in humans. Obesity. 2019 ...