An interventional study of 40-minute one-on-one dietary counseling and nutrition education aimed at reducing ultra-processed food consumption and Standard dietary counseling and nutrition education based on national guidelines in Postprandial Glucose, Glucose Levels and Hyperglycemias, sponsored by Korea University. Recruiting at 1 site in South Korea. Open to participants aged 20 Years to 39 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-04-17.
Sponsored by Korea University · Not applicable, Interventional, and Prevention
The goal of this trial is to investigate whether reduction in ultra-processed food intake through dietary counseling and education can improve postprandial glucose responses and glycemic variability compared with a usual diet in young, healthy Korean adults aged 20-30 years. The main questions it aims to answer are:
- Does reducing ultra-processed food intake, while maintaining total energy intake and usual lifestyle behaviors, improve postprandial glucose and lower glycemic variability in healthy adults without diabetes?
Participants will:
The Ultra-Processed Food Reduction Intervention and Continuous Glucose Monitoring (ULTRA-CGM) trial is a parallel, two-arm randomized controlled trial designed to evaluate the effects of a ultra-processed food (UPF)-reducing dietary intervention on postprandial glucose responses and glycemic variability in young Korean adults (aged 20-39 years) using CGM devices. Participants will be randomly assigned to either a UPF-reducing intervention group or a control group maintaining their usual diet. We hypothesize that receiving the UPF-reducing dietary intervention will improve postprandial glucose responses and reduce glycemic variability compared with participants receiving standard dietary counseling based on national guidelines. The findings from this trial may provide experimental evidence on the metabolic effects of reducing UPF consumption and inform dietary strategies for diabetes prevention among younger adults.
800 studies on the registry are indexed under Hyperglycemia; 115 are open to participants now.
This study's planned enrollment of 50 is close to the median of 50 across 620 interventional studies indexed under Hyperglycemia.
Browse Hyperglycemia studies →Korea University is the lead sponsor of 64 studies on the registry; 7 are open to participants now.
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Exclusion Criteria:
Participants will be randomly assigned to the intervention group using block randomization with a 1:1 allocation ratio.
Behavioral: 40-minute one-on-one dietary counseling and nutrition education aimed at reducing ultra-processed food consumption
Participants will be randomly assigned to the control group using block randomization with a 1:1 allocation ratio.
Behavioral: Standard dietary counseling and nutrition education based on national guidelines
Participants assigned to the intervention group receive a 40-minute one-on-one nutrition education session and personalized dietary counseling delivered by the study dietitian. The goals of these sessions are to reduce UPF consumption while maintaining total energy intake and usual lifestyle behaviors. All sessions follow a standardized protocol to ensure consistent delivery of the intervention. The study dietitian delivering the intervention receives training on the standardized protocol prior to participant enrollment.
Participants assigned to the control group are also provided with a 40-minute one-on-one nutrition education session and personalized dietary counseling, but with different objectives. During these sessions, the national dietary guidelines are introduced using an educational leaflet distributed by the Ministry of Health and Welfare. The education session and counseling provided to the control group do not include any information on UPFs. After completion of the study, participants in the control group are provided with the same nutrition education materials on UPF reduction that are used in the intervention group.
Change in postprandial glucose responses
The primary outcome of this study is the change in postprandial glucose responses from the baseline monitoring period to the post-intervention monitoring period. Postprandial glucose responses are assessed using CGM and quantified as the incremental area under the curve (iAUC) over 2 hours following each meal. Higher iAUC values indicate greater postprandial glucose excursions. For each meal, iAUC is calculated as the area under the curve above the baseline level over the 2-hour postprandial period, using the trapezoidal rule. The baseline glucose level is defined as the mean glucose value in the 5 minutes immediately preceding meal consumption. For overlapping meals, the iAUC for the first meal is calculated from its start until 2 hours after, and overlapping periods are excluded from subsequent meals' iAUC to ensure each glucose excursion is counted once.
Time frame: Change in mean values from the baseline monitoring period (10-day period before the intervention) to the post-intervention monitoring period (10-day period immediately following the intervention)
Change in coefficient of variation (CV)
CV indicates relative glycemic variability and is calculated as the standard deviation of glucose measurements assessed using CGM divided by the mean glucose level.
Time frame: Change in mean values from the baseline monitoring period (10-day period before the intervention) to the post-intervention monitoring period (10-day period immediately following the intervention)
Change in standard deviation (mg/dL)
Standard deviation represents the absolute magnitude of glycemic variability, reflecting the dispersion of glucose values over time, assessed using CGM.
Time frame: Change in mean values from the baseline monitoring period (10-day period before the intervention) to the post-intervention monitoring period (10-day period immediately following the intervention)
Change in mean amplitude of glycemic excursions (MAGE)
Mean amplitude of glycemic excursions represents the mean amplitude of major glucose excursions. It is calculate by mean height of glycemic excursions (peaks and nadirs) that exceed one SD of the mean glucose over a 24-hour period.
Time frame: Change in mean values from the baseline monitoring period (10-day period before the intervention) to the post-intervention monitoring period (10-day period immediately following the intervention)
Change in glucose spike frequency
Glucose spike frequency quantifies the number of distinct glucose excursions above 140 mg/dL, providing an additional measure of postprandial hyperglycemia.
Time frame: Change in mean values from the baseline monitoring period (10-day period before the intervention) to the post-intervention monitoring period (10-day period immediately following the intervention)
Change in time-in-range (%)
Time-in-range represents the percentage of time spent within the consensus target glucose range of 70-180 mg/dL, as defined by international continuous glucose monitoring consensus recommendations.
Time frame: Change in mean values from the baseline monitoring period (10-day period before the intervention) to the post-intervention monitoring period (10-day period immediately following the intervention)
Change in time-in-tight-range (%)
Time-in-tight-range represents the percentage of time spent within the tighter target range of 70-140 mg/dL. Because participants are healthy young adults, time-in-tight-range 70-140 mg/dL is considered.
Time frame: Change in mean values from the baseline monitoring period (10-day period before the intervention) to the post-intervention monitoring period (10-day period immediately following the intervention)
Change in time-above-range (%)
Time-above-range represents the percentage of time spent with glucose levels above 180 mg/dL or 140 mg/dL. Because participants are healthy young adults, time-above-range 140 mg/dL is considered.
Time frame: Change in mean values from the baseline monitoring period (10-day period before the intervention) to the post-intervention monitoring period (10-day period immediately following the intervention)
Change in time-below-range (%)
Time-below-range represents the percentage of time spent with glucose levels below 70 mg/dL
Time frame: Change in mean values from the baseline monitoring period (10-day period before the intervention) to the post-intervention monitoring period (10-day period immediately following the intervention)
Change in body weight (kg)
Body weight will be directly measured by study staff to assess overall adiposity.
Time frame: Change from study enrollment (day 1) to study completion (day 23; 10 days after the intervention)
Change in waist circumference (cm)
Waist circumference will be directly measured by study staff to assess central adiposity.
Time frame: Change from study enrollment (day 1) to study completion (day 23; 10 days after the intervention)
Change in fat mass (kg)
Fat mass will be measured using a bioelectrical impedance analyzer (BIA) (InBody 270S; InBody Co., Ltd, Seoul, Korea).
Time frame: Change from study enrollment (day 1) to study completion (day 23; 10 days after the intervention)
Change in muscle mass (kg)
Muscle mass will be measured using a bioelectrical impedance analyzer (BIA) (InBody 270S; InBody Co., Ltd, Seoul, Korea).
Time frame: Change from study enrollment (day 1) to study completion (day 23; 10 days after the intervention)
Change in percentage of body fat (%)
Percentage of body fat will be measured using a bioelectrical impedance analyzer (BIA) (InBody 270S; InBody Co., Ltd, Seoul, Korea).
Time frame: Change from study enrollment (day 1) to study completion (day 23; 10 days after the intervention)
Change in blood pressure measurements (mmHg)
Blood pressures measurements, including both systolic and diastolic values, are measured to capture potential cardiometabolic effects of the intervention. Blood pressure is measured by a trained study nurse (a registered nurse) on the upper arm using an automated blood pressure monitoring device (WatchBP office Target BP3MD1-4; Microlife AG, Switzerland) while participants are seated and at rest. The mean of three consecutive measurements is used for analysis.
Time frame: Change from study enrollment (day 1) to study completion (day 23; 10 days after the intervention)
Change in handgrip strength (kg)
Handgrip strength is assessed as a marker of muscular strength and functional status. Handgrip strength is assessed using a handgrip dynamometer (T.K.K.-5401; Takei Scientific Instruments Co., Ltd, Tokyo, Japan). Handgrip measurements are performed twice for each hand in an alternating manner, and the highest value is used for analysis
Time frame: Change from study enrollment (day 1) to study completion (day 23; 10 days after the intervention)
Plan to share: No — To protect personal information, data files containing personally identifiable information will be accessible only to designated researchers, and any external transfer of related data will be strictly prohibited.
Started Oct 2025 (actual). Primary completion is estimated for Aug 2026, 10 months after the start.
Of 208 non-industry interventional studies with no phase under Hyperglycemia, half reached primary completion within 14 months of starting (the median), counting those still running; a quarter within 9 and three quarters within 27. This study's planned 10 months is below that.
Counting every sponsor, half of 225 studies reached it within 14 months; a quarter within 7 and three quarters within 27.
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