Effects of meal timing on weight loss and health

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

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.

Why it matters

Who can join: the full rules

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 it's running

• Healthy Eating and Activity Laboratory
  Knoxville, Tennessee, United States Recruiting

Study contacts

• Study coordinator: Hollie A Raynor, PhD
• Email: hraynor@utk.edu
• Phone: 865-974-9126

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.