Effect of Circadian Timing of a Standardized Meal on Postprandial Glucose Response in Healthy Adults

This randomized crossover study aims to investigate the effect of circadian timing of a standardized meal (morning versus evening consumption) on postprandial glucose response in healthy adults. Postprandial glucose will be assessed using the incremental area under the curve (iAUC) over 120 minutes.

Study Overview

• Status: Not yet recruiting
• Conditions: Meal Timing; Glycemic Response to Feeding in Healthy Participants; Postprandial Glucose
• Intervention / Treatment: Other: Standardized Test Meal

• Study Type: Interventional
• Enrollment (Estimated): 32
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Wafa Alotaibi, PhD; Phone Number: +966500358622; Email: Walotaibi@kfu.edu.sa

Study Locations

• Saudi Arabia
  • Eastern Province
    • Al-Ahsa, Eastern Province, Saudi Arabia, 31982
      • King Faisal University
      • Contact: Wafa Alotaibi; Phone Number: +966500358622; Email: Walotaibi@kfu.edu.sa

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy adults aged 18 years and older
• Able and willing to provide informed consent
• Able to comply with study procedures

Exclusion Criteria:

• Diagnosis of diabetes or any metabolic disorder affecting glucose regulation
• Use of any medications
• Pregnant or breastfeeding women
• Night shift workers or individuals with irregular sleep patterns

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Morning Meal Condition; Participants will consume a standardized test meal in the morning following an overnight fasting period of at least 8 hours. Postprandial glucose will be measured over 120 minutes.	Other: Standardized Test Meal; The standardized test meal provided 50 g of carbohydrates of weighed portions of white bread and jam, served with 200 mL of water.
Experimental: Evening Meal Condition; Participants will consume the same standardized test meal in the evening following a standardized fasting period of at least 8 hours prior to the test meal. Postprandial glucose will be measured over 120 minutes.	Other: Standardized Test Meal; The standardized test meal provided 50 g of carbohydrates of weighed portions of white bread and jam, served with 200 mL of water.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incremental Area Under the Curve (iAUC) for Postprandial Glucose	The primary objective of this study is to investigate the effect of circadian timing of a standardized test meal (morning versus evening consumption) on postprandial glucose response in healthy adults, assessed as the incremental area under the curve (iAUC) for capillary blood glucose over 120 minutes following meal consumption	Baseline to 120 minutes after consumption of the standardized test meal

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peak Postprandial Glucose (Morning vs Evening)	Peak capillary blood glucose concentration measured within 120 minutes after consumption of the standardized test meal, under morning and evening conditions	Baseline to 120 minutes after consumption of the standardized test meal
Time to Peak Glucose (Morning vs Evening)	Time required to reach peak capillary blood glucose concentration following meal consumption, under morning and evening conditions.	Baseline to 120 minutes after consumption of the standardized test meal
Postprandial Glucose Profile (Morning vs Evening)	Capillary blood glucose concentrations measured at predefined time points following consumption of the standardized test meal, under morning and evening conditions.	Baseline, 15, 30, 60, 90, and 120 minutes after consumption of the standardized test meal

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Night Eating Behavior	Night eating behavior will be assessed using the validated Night Eating Questionnaire to characterize nocturnal eating patterns and support interpretation of variability in postprandial glucose responses.	Baseline
Sleep Duration and Quality	Sleep duration and quality will be assessed using a validated sleep questionnaire administered prior to each study visit to support interpretation of postprandial glucose responses.	Baseline
Chronotype	Chronotype will be assessed at baseline using the validated Questionnaire to characterize individual circadian preference and support interpretation of postprandial glucose responses.	Baseline

Collaborators and Investigators

• Sponsor: King Faisal University
• Collaborators: Saudi Food and Drug Authority

Study record dates

Study Major Dates

• Study Start (Estimated): April 15, 2026
• Primary Completion (Estimated): May 30, 2026
• Study Completion (Estimated): May 30, 2026

Study Registration Dates

• First Submitted: April 16, 2026
• First Submitted That Met QC Criteria: April 16, 2026
• First Posted (Actual): April 22, 2026

Study Record Updates

• Last Update Posted (Actual): April 22, 2026
• Last Update Submitted That Met QC Criteria: April 16, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: ETHICS3992

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: De-identified individual participant data (IPD) collected in this study will not be made publicly available. Data will be used for research purposes by the study investigators only

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No