An interventional study of High-Protein, High-Fiber Meal and Low-Protein, Low-Fiber Meal in Glycemic Response; Satiety, Fasting, Time Restricted and Dietary Intervention, sponsored by King Faisal University. Recruiting at 1 site in Saudi Arabia. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-03-12.
Sponsored by King Faisal University · Not applicable, Interventional, and Prevention
This randomized crossover study investigates the effect of consuming a high-protein, high-fiber pre-fast meal on subjective satiety and glycemic responses during fasting hours in healthy adults. Participants will complete two dietary conditions in a randomized order: a standardized high-protein, high-fiber pre-fast meal and a low-protein, low-fiber pre-fast meal guided by dietary instructions. Each condition will be followed for two consecutive days and separated by a three-day washout period. Outcomes include subjective appetite sensations during fasting hours, glycemic profiles assessed using continuous glucose monitoring (CGM), and exploratory analyses examining the association between glucose dynamics and appetite sensations.
This study is a randomized crossover interventional trial conducted in healthy adults to evaluate the effect of a high-protein, high-fiber pre-fast meal on subjective satiety and glycemic responses during fasting hours.
Each participant will complete two study conditions in a randomized sequence: a high-protein, high-fiber pre-fast meal condition and a low-protein, low-fiber pre-fast meal condition. Each condition will be followed for two consecutive days and separated by a three-day washout period to minimize potential carryover effects.
During the high-protein, high-fiber condition, participants will consume a standardized pre-fast meal consisting of oats (40 g), Greek yogurt (160 g), peanut butter (16 g), dried cranberries (10 g), and almonds (6 g). Meals will be provided in pre-measured portions by the research team.
During the low-protein, low-fiber condition, participants will receive standardized written dietary instructions, including a list of foods to avoid, to guide consumption of a low-protein, low-fiber pre-fast meal. No calorie restriction will be applied in either study condition.
Subjective appetite sensations, including hunger, fullness, desire to eat, and prospective food consumption, will be assessed using visual analogue-type scales at predefined time points across the fasting day. Glycemic profiles will be continuously assessed using continuous glucose monitoring (CGM).
Exploratory analyses will examine temporal associations between CGM-derived glucose levels and glucose trends and subjective appetite sensations across the study day.
333 studies on the registry are indexed under Intermittent Fasting; 99 are open to participants now.
This study's planned enrollment of 38 is below the median of 50 across 320 interventional studies indexed under Intermittent Fasting.
Browse Intermittent Fasting studies →King Faisal University is the lead sponsor of 15 studies on the registry; 2 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants consume a standardized high-protein, high-fiber pre-fast meal for two consecutive days.
Other: High-Protein, High-Fiber Meal
Participants follow standardized written dietary instructions to consume a low-protein, low-fiber pre-fast meal for two consecutive days.
Other: Low-Protein, Low-Fiber Meal
Participants consume a standardized high-protein, high-fiber pre-fast meal consisting of oats (40 g), Greek yogurt (160 g), peanut butter (16 g), dried cranberries (10 g), and almonds (6 g) for two consecutive days.
Participants follow standardized written dietary instructions, including a list of foods to avoid, to consume a low-protein, low-fiber pre-fast meal for two consecutive days. No calorie restriction is applied.
Daytime Satiety During Fasting Hours
Subjective appetite sensations including hunger, fullness, desire to eat, and prospective food consumption assessed using a visual analogue-type scale with numeric anchors ranging from 0 to 10.
Time frame: Assessed at baseline prior to the pre-fast meal, 30 and 60 minutes post-meal, mid-afternoon (approximately 4:00 PM), and 30 minutes prior to breaking the fast during each intervention condition.
Glycemic Profiles During Fasting (CGM)
Interstitial glucose levels assessed using continuous glucose monitoring (CGM) to evaluate glucose patterns and variability during fasting hours.
Time frame: Assessed on Day 1 and Day 2 of each intervention period during the fasting window from completion of the pre-fast meal until breaking the fast.
Post-Meal CGM Glucose Response
Continuous glucose monitoring-derived glucose response in the 0-120 minutes following consumption of the pre-fast meal, including peak glucose and incremental area under the curve (iAUC).
Time frame: 0-120 minutes after the pre-fast meal during each intervention condition.
Association Between Glucose and Appetite (Exploratory)
CGM Glucose Concentration and Subjective Appetite Ratings at Predefined Time Points
Time frame: Assessed on Day 1 and Day 2 of each intervention period at the predefined appetite assessment time points: baseline prior to the pre-fast meal, 30 minutes post-meal, 60 minutes post-meal, 4:00 PM, and 30 minutes prior to breaking the fast.
Plan to share: No — 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
No publications or documents are linked to this record.
Started Feb 2026 (actual). Primary completion is estimated for Mar 2026, 1 month after the start.
Of 257 non-industry interventional studies with no phase under Intermittent Fasting, half reached primary completion within 18 months of starting (the median), counting those still running; a quarter within 9 and three quarters within 34. This study's planned 1 month is below that.
Counting every sponsor, half of 263 studies reached it within 17 months; a quarter within 8 and three quarters within 34.
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