Effects of meal timing on weight loss and health

Effect of Time-based Energy Intake Goals on Weight Loss During Obesity Treatment

Not applicable Interventional The University of Tennessee, Knoxville · NCT06455995

This study is testing whether eating most of your calories in the morning or evening helps adults with overweight or obesity lose weight and improve their health better than just following a regular diet and exercise plan.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment174 (estimated)
Ages25 Years to 60 Years
SexAll
SponsorThe University of Tennessee, Knoxville Academic / other
Locations1 site (Knoxville, Tennessee)
Trial IDNCT06455995 on ClinicalTrials.gov

What this trial studies

This randomized controlled trial investigates how the timing of calorie intake influences long-term weight loss in adults with overweight or obesity over a 12-month period. Participants are assigned to one of three groups: a morning-loaded calorie intake, an evening-loaded calorie intake, or a standard lifestyle intervention without specific timing guidance. All groups follow a reduced-calorie, low-fat diet and engage in physical activity while receiving cognitive behavioral support. The study aims to understand the impact of meal timing on weight loss, appetite regulation, and overall health.

Who should consider this trial

Good fit: Ideal candidates are adults with a body mass index (BMI) between 27 and 45 kg/m2 who are willing to follow a structured diet and exercise program.

Not a fit: Patients with diabetes requiring specific meal timing, significant sleep issues, or those unable to engage in physical activity may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide insights into effective dietary strategies for weight management and obesity treatment.

How similar studies have performed: Other studies have explored meal timing and weight loss, but this specific approach focusing on time-based energy intake goals is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Body mass index (BMI) between 27 and 45 kg/m2.

Exclusion Criteria:

* Report not regularly (\>/= 5 days/wk) consuming energy (\>/= 100 kcal) prior to 12 pm, and not being able to consume energy every day (\>/= 50 kcal) within one hour of awakening.
* Report taking sleep medication or not regularly (\>/= 5 nights/wk) getting at least 6 hrs of total sleep.
* Report being a shift workers/alternative shift workers that work outside of 7 am and 7 pm.
* Report being diagnosed with type 1, or type 2 diabetes and taking medication that requires eating to occur at certain time periods.
* Report a heart condition, chest pain during periods of activity or rest, or loss of consciousness on the Physical Activity Readiness Questionnaire (PAR-Q). Individuals reporting joint problems, prescription medication usage, or other medical conditions that could limit exercise will be required to obtain written physician consent to participate.
* Report being unable to walk for 2 blocks (1/4 mile) without stopping.
* Report major psychiatric diseases or organic brain syndromes.
* Report currently participating in a weight loss program and/or taking weight loss or appetite regulation medication or lost \>/= 5% of body weight during the past 6 months.
* Report having bariatric surgery for weight loss/planning to have bariatric surgery in the next 12 months.
* Report being pregnant, lactating, \< 6 months post-partum or plan to become pregnant (next 12 months).
* Report planning to move outside of the metropolitan area within the time frame of the investigation.
* Do not have daily access to PC with internet or smartphones (needed for self-monitoring).

Where this trial is running

Knoxville, Tennessee

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Obesity
Last reviewed 2026-06-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.