Impact of Meal Timing on Glycemic Profile in Latino Adolescents With Obesity: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Impact of Meal Timing on Glycemic Profile in Latino Adolescents With Obesity (NCT05391438), a na na study. The primary outcome is Change in Insulinogenic Index From Baseline After Test Meal From Venous Sample.

2. Clinical Question

The clinical question concerns the timing of food intake and a laboratory measure related to early insulin secretion. It is not a comparison of a meal-timing program against usual care or a separate control intervention. The registry describes three test-meal times but does not report numerical insulinogenic-index results or a statistical comparison of those conditions.

The registry’s background discusses interest in time-restricted eating, which involves a longer daily fasting interval and a defined eating window. However, the intervention description available in the record specifies test meals at three times over two weeks; it does not establish that participants followed a particular daily fasting duration or eating-window schedule. The research question should therefore be read in terms of the recorded test-meal timing conditions rather than as evidence about every form of time-restricted eating.

3. Trial Design

This is a completed, single-group study with an enrollment of 22. The registry lists the phase as not applicable and allocation as not applicable. Masking is listed as none. The study start is recorded as 2022-09-01, and primary completion is recorded as 2023-08-01.

All participants were to receive the three standard test meals in random order over two weeks. The conditions are early, with a meal at 8 AM; afternoon, with a meal at 12 PM; and late, with a meal at 4 PM. Because the same participants undergo the different timing conditions, the design is structurally different from a parallel-group trial in which different groups each receive one condition. The random order refers to the order of the test meals; it does not make the study a randomized comparison between independent groups.

The intervention is listed as “Meal-timing” and categorized as “Other.” The available intervention description begins to mention placement of a continuous glucose monitor, but the description is truncated in the registry record. Further details about monitoring procedures, adherence, test-meal composition, participant instructions, or the timing of all study visits are not reported in the registry record.

The listed primary outcome is change in insulinogenic index from baseline after a test meal, measured from venous samples, with a timeframe from baseline to Day 14. The registry also names a secondary outcome concerning change in glucagon-like peptide 1 concentrations after a test meal. It lists three outcome measures overall, but details for all of them are not reported in the registry record. Numerical outcome results and analysis results are not reported in the registry record, so the completed status alone does not establish what the study found.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Change in Insulinogenic Index From Baseline After Test Meal From Venous Sample, measured over Baseline to Day 14.

The primary endpoint is change in the insulinogenic index from baseline after a test meal, assessed from venous samples over the period from baseline to Day 14. The index is defined in the registry as change in insulin divided by change in glucose over the first 30 minutes after the test-meal load. Samples for glucose, insulin, and C-peptide are described at multiple time points from -10 minutes through 180 minutes after the meal.

The endpoint is intended to characterize early insulin secretion in response to a glucose load from a meal. The registry states that the index has been widely used in clinical studies, is highly correlated with acute insulin response on an intravenous glucose tolerance test, and is considered a reasonable surrogate. These statements describe the rationale for using the measure; they do not provide a result from this study or establish that the index captures every aspect of glucose regulation.

The record specifies a median as the summary parameter and an interquartile range as the measure of dispersion. A median describes the middle of an ordered set of measurements, while the interquartile range describes the spread across the middle portion of those measurements. These summaries can be useful when a distribution is skewed or when extreme values make a mean and standard deviation less representative. The registry record does not report the endpoint values, the number of participants with usable samples, or the statistical comparison used to summarize change across the meal-timing conditions.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the endpoint summary represent?

The primary outcome is described using a median and an interquartile range. General statistical explanation: the median is the central observation after values are ordered. The interquartile range describes the span of the central half of the observations. These summaries can make the location and variability of a set of measurements easier to understand when the distribution is asymmetric or includes unusually high or low values. They do not, on their own, quantify uncertainty in an estimate of a treatment contrast. A confidence interval would serve a different purpose by expressing a range of estimates compatible with the observed data under a specified statistical model.

The registry’s endpoint description defines the insulinogenic index as the change in insulin divided by the change in glucose over the first 30 minutes after the test-meal load. It also describes venous sampling for glucose, insulin, and C-peptide at multiple time points. Repeated samples within a participant provide a profile of response over time, rather than a single independent observation at every time point. The registry does not report how those measurements were combined for analysis beyond the endpoint definition and stated summary parameter.

Why does the repeated-measures structure matter?

General statistical explanation: when each participant contributes measurements under several conditions, those measurements are usually correlated because they come from the same person. An analysis that recognizes this dependence can compare conditions while accounting for participant-level differences. A paired analysis, a repeated-measures model, or another suitable approach may be considered in general, depending on the outcome distribution and study design. The registry record does not report which method was used, so no particular model should be attributed to this study.

The random order of meal timing is a design feature, but it does not replace an analysis plan. In general, a repeated-condition study may need to consider order and period effects, and whether the interval between conditions is adequate to prevent carryover. The registry record does not report whether such effects were assessed, how sequence was represented, or whether any participant failed to complete one or more conditions. It also does not report whether the final analysis used all enrolled participants or only those with complete measurements.

What can be concluded without estimates or uncertainty intervals?

General statistical explanation: an estimated contrast describes the difference in an outcome between conditions, while its confidence interval communicates the precision of that estimate under the analysis assumptions. A p-value, when reported, addresses compatibility of the observed data with a specified null hypothesis under a statistical model; it does not measure the probability that a hypothesis is true or indicate the clinical importance of a result. The registry record reports no numerical endpoint estimates, confidence intervals, or p-values. It is therefore not possible to assess statistical evidence, precision, or the range of differences consistent with the results.

A nonsignificant result, if one were reported, would not automatically demonstrate equivalence or no meaningful difference. Such a conclusion would require an appropriate design and a prespecified margin for what counts as a sufficiently small difference. The registry record does not report an equivalence or noninferiority framework or a margin. Likewise, a statistically significant contrast would not by itself establish clinical importance. The size and uncertainty of the estimated difference, the measure’s interpretation, and the study context would matter.

How should planning illustrations be understood?

General statistical explanation: sample-size calculations are planning tools that depend on assumptions about the effect to detect, variability, significance threshold, allocation, and analysis. They are not observed outcomes and do not reveal the probability that a completed study produced a statistically significant result. The registry record includes a planning-illustration description based on an observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says that the target effect is a stated fraction of the observed effect and distinguishes participant counts per arm from total event counts for time-to-event calculations.

Those assumptions describe an illustration, not the trial’s own design justification. The trial itself is recorded as single-group, with repeated meal-timing conditions, rather than an equal-allocation two-arm comparison. The registry record does not report a prospective sample-size justification or explain how any planning illustration relates to the repeated-condition analysis. Planning illustrations should therefore not be read as observed power, as proof that the study was adequately sized, or as a result from the trial.

What does over-dispersion mean in general?

General statistical explanation: over-dispersion occurs when the variability in observed data exceeds what a statistical model assumes. If it is ignored, standard errors and confidence intervals can be too optimistic, and tests can give misleading evidence. It can arise in count outcomes and other settings, depending on the model and data-generating process. The registry does not report an over-dispersion assessment, and the primary endpoint is described as an insulinogenic index summarized by a median and interquartile range. No claim about over-dispersion or a particular distribution can be made for this study from the record.

The principal methods limitation is thus not that a particular statistical method is demonstrably unsuitable, but that the registry record does not report the analysis details needed to evaluate it. The outcome definition and summary format are available, while the model, contrast, assumptions, uncertainty estimates, and analysis population are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The study lists a primary outcome, a secondary outcome concerning change in glucagon-like peptide 1 concentrations, and three outcome measures overall. The registry does not give full details for every outcome measure. It also does not report a multiplicity strategy, such as prioritizing a particular set of comparisons or adjusting statistical inference for multiple outcomes or multiple pairwise meal-time contrasts. Without this information, the extent to which any reported statistical evidence would account for multiple opportunities to find a difference is not reported in the registry record. No numerical analysis results are reported in any case.

Missing-data handling is not reported in the registry record. The available information does not say how missing venous samples, incomplete meal conditions, or unusable measurements were handled, whether participants were excluded from particular analyses, or whether any imputation was planned or used. Enrollment of 22 does not establish that all 22 participants contributed complete primary-endpoint data for all conditions.

The analysis population is also not reported in the registry record. The registry does not specify whether analyses included everyone enrolled, only participants who completed all three test meals, or a different group defined by measurement availability or adherence. A clear account of the analysis population and missing observations would be needed to understand how the reported summaries relate to the enrolled participants.

These omissions limit assessment of selective analysis and robustness. They do not demonstrate that data were missing or that analyses were improperly conducted; they mean that these details cannot be evaluated from the registry record.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

The registry lists the Early, Afternoon, and Late conditions separately. For each listing, 22 participants are recorded as at risk for serious events and 22 as at risk for other events. The recorded counts are zero serious events, zero other events, and zero deaths for each condition.

These are event-count entries, not estimates of comparative risk. Since the study is single-group and each participant was scheduled to receive all three meal-timing conditions, the three listings should not be interpreted as three independent groups of 22 participants. Nor do identical counts establish that the conditions have equivalent safety profiles. The registry record does not report a statistical comparison of events or details on the event-collection period.

Zero recorded events means that no events were listed in these categories in the registry record. It does not establish that an event was impossible, that every participant completed every condition, or that all potential adverse effects were assessed and recorded. Further information about safety monitoring, event definitions, follow-up, and reporting completeness is not reported in the registry record.

12. What the Result Does, and Does Not, Mean

The record establishes that a completed study enrolled 22 Latino adolescents with obesity and scheduled each participant for test meals at early, afternoon, and late times in random order over two weeks. It identifies change in insulinogenic index as the primary endpoint and describes how that measure is calculated from insulin and glucose responses after a meal. It also records zero serious events, zero other events, and zero deaths in each meal-timing listing.

Those details do not show what happened to the insulinogenic index. Numerical outcome results, estimated comparisons, confidence intervals, and p-values are not reported in the registry record. Readers therefore cannot determine from this record whether responses differed across the three meal times, how large any difference was, or how precisely a difference was estimated. The completed status is not a substitute for outcome findings.

The design also defines the limits of the question. It is a single-group, repeated-condition study of test meals at specified times, not a comparison against an independent control group. The registry does not establish that participants followed a sustained time-restricted eating schedule, and the available description does not provide a complete account of the monitoring protocol. The study therefore cannot be treated, on the basis of this record alone, as a test of all meal-timing approaches or a comprehensive obesity intervention.

The registry’s description of insulinogenic index as a surrogate for early-phase insulin secretion explains why the outcome may be of research interest. A surrogate measure is not the same as a direct measure of long-term health or clinical benefit. General statistical principle: interpretation depends on both the estimated effect and its uncertainty, as well as on what the measure captures and the population studied. None of those outcome estimates or uncertainty measures is available in the registry record.

The appropriate conclusion is narrow: the registry describes the study question and design but does not provide enough numerical outcome information to characterize the primary result. Claims about a beneficial, harmful, or null effect would go beyond what the record reports.

13. Why This Trial Matters Statistically

Statistically, this study raises a design issue common to meal-timing and other repeated-condition research: comparisons within the same participant differ from comparisons between independent groups. When one person contributes measurements under several conditions, the analysis needs to account for the relationship among those measurements. This can sometimes make within-person comparisons informative, but only when the design, measurement process, and analysis are described clearly.

The random order of the early, afternoon, and late test meals is relevant because sequence can influence measured responses. A complete statistical account would make clear how condition order and repeated measurements were handled. Those analysis details are not reported in the registry record. The absence of that information makes it difficult to judge how the design was translated into an estimate of the meal-timing contrast.

The endpoint also illustrates the difference between a physiological measure and a clinical outcome. The insulinogenic index is presented as a measure related to early insulin secretion and as a reasonable surrogate. That provides a rationale for studying it, but does not make it interchangeable with long-term health outcomes. Clear interpretation requires both a transparent definition of the endpoint and estimates with enough precision to assess their possible importance.

Finally, the registry’s completed status and safety counts cannot stand in for the primary efficacy results. Outcome summaries and uncertainty estimates are needed to evaluate what the study found. Because those results are not reported in the registry record, the study’s statistical contribution cannot be assessed beyond its recorded design, endpoint definition, and event counts.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry record has important reporting gaps for interpreting this study. It does not report numerical results for the primary insulinogenic-index endpoint, the named secondary outcome, or the statistical analyses. Estimated differences, confidence intervals, and p-values are not reported, so neither the direction nor precision of any contrast can be assessed.

The intervention description is incomplete: it ends after beginning to describe continuous glucose monitor placement. Details about the full monitoring procedure, the test meals, adherence, and the exact conduct of the repeated conditions are not reported in the registry record. The record does not establish that the study tested a sustained daily fasting schedule, even though its background discusses time-restricted eating.

Although the order of test meals is described as random, the record does not explain how order was implemented or addressed in analysis. It also does not report the statistical model, analysis population, missing-data handling, or multiplicity approach. The registry lists three outcome measures but does not provide full details for all of them.

The sample size of 22 and the single-group design restrict what can be inferred about broader populations or comparisons with separate control groups. No external comparison group is recorded, and no basis is available in the registry record for assessing whether the enrolled participants represent other adolescents with obesity. These are limits on what can be concluded from the registry information, not evidence that the study procedures or analyses were necessarily inadequate.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Impact of Meal Timing on Glycemic Profile in Latino Adolescents With Obesity — NCT05391438.
• Registry record last updated 2024-10-23; status last verified 2024-10.
• Results first posted 2024-10-23.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry describes a completed, single-group study with 22 enrolled Latino adolescents with obesity. Each participant was scheduled to consume standard test meals in random order at 8 AM, 12 PM, and 4 PM over two weeks. The primary outcome is change in insulinogenic index from baseline after a test meal, measured from venous samples over baseline to Day 14 and summarized using a median and interquartile range.

The record names a secondary outcome concerning glucagon-like peptide 1 concentrations and lists three outcome measures overall. It records zero serious events, zero other events, and zero deaths for each timing condition. Numerical outcome results, analysis methods, missing-data handling, and analysis populations are not reported in the registry record. The available information supports a description of the study design and endpoint, but not a quantitative conclusion about differences among meal times.