Effect of Snacks on Appetite Control: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effect of Snacks on Appetite Control (NCT01806688), a randomized na study. The primary outcome is Total Area Under the Curve (AUC) for Hunger, Fullness, Desire to Eat and Prospective Consumption Using Visual Analog Scales (VAS).

2. Clinical Question

3. Trial Design

This was a randomized, single-masked, crossover study. Its registry title describes a controlled study of snacks and appetite control, and the record lists two components: the Seed Study and the Pita Study. Enrollment was 46 overall; 30 participants were in both studies and 16 enrolled in just one. The record reports 38 participants in each study. These enrollment figures describe participation, but do not establish how many participants contributed usable observations to each endpoint or analysis.

A crossover design generally compares interventions experienced by the same participant, allowing each participant to serve as their own control for some sources of variation. That is a general feature of the design, not a description of the specific analysis used in this trial. The treatment sequence, allocation ratio, timing between intervention visits and any washout arrangements are not reported in the registry record. The identity of the person or group masked is also not reported.

The registry lists five interventions, including higher-protein or higher-protein-and-fibre snacks, comparator snacks with lower protein and/or fibre, and a non-caloric control. The study summary describes different snack comparisons within the Seed and Pita studies. The detailed arm descriptions are incomplete, so the full composition of every snack and comparator cannot be established from the registry record.

The study was marked completed. Its recorded start date was 2013-07-06 and its primary completion date was 2014-08-23. The phase is listed as NA. The registry record does not report a protocol-level account of the randomization procedure, adherence, or the analysis population.

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.

Before assignment: 30 people completed both studies and 16 participated in only 1 study.

First Intervention Seed Study

Second Intervention Seed Study

Third Intervention Seed Study

First Intervention Pita Study

Analysis population for the primary outcome, as defined in the registry: A total of 46 participants were enrolled in the Seed and the Pita Study. Of these 46, 30 participated in both studies and 16 enrolled in just one study. 38 participants enrolled in the Seed Study and 38 in the Pita 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.

Population: There are two arms to this study, the Seed Study and the Pita Study. A total of 46 participants were enrolled in the overall study, and of those 46 enrolled, 30 people participated in both studies while 16 only participated in one study. 38 participants were randomized to complete the Seed Study and 38 participants were randomized to complete the Pita Study.

6. Primary Endpoint

The registry lists the primary outcome as Total Area Under the Curve (AUC) for Hunger, Fullness, Desire to Eat and Prospective Consumption Using Visual Analog Scales (VAS), measured over VAS administered pre-snack and then every 30 minutes after the first bite up to 180 minutes for a total of 7 time points..

The primary endpoint was total area under the curve for hunger, fullness, desire to eat and prospective consumption, measured using visual analog scales. The questionnaire asked participants how hungry and full they felt, how strong their desire to eat was, and how much they thought they wanted to eat. Each response was marked on a line anchored by opposing descriptions, with the response converted to a distance in centimeters from the left anchor.

Ratings were collected before the snack and every 30 minutes after the first bite up to 180 minutes, for a total of 7 time points. The registry says that the ratings over time were graphed and that area under the curve was calculated using the trapezoid method. This method approximates the accumulated response over the assessment period by joining successive measurements and estimating the area beneath the resulting line segments. The endpoint unit was cm x min.

Area under the curve can represent the overall pattern of a repeated rating over a defined period, rather than focusing on a single measurement. It can therefore summarize both the level and persistence of reported appetite sensations across the measurement window. The four appetite questions remain distinct domains, however; an area under the curve for one question does not automatically represent the others. The registry record does not report a single primary-outcome comparison or estimates for these domains.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does area under the curve represent?

The primary endpoint combines repeated appetite ratings across the assessment period. The registry describes VAS measurements before the snack and every 30 minutes after the first bite up to 180 minutes, producing 7 time points. The ratings were plotted over time and integrated using the trapezoid method. In general, the trapezoid method approximates the area under a changing measurement by treating the segment between neighboring observations as a straight line. The resulting endpoint summarizes accumulated ratings across the measurement window rather than reporting only a single rating.

The unit, cm x min, reflects the rating scale and the time dimension of the integrated measure. The endpoint was calculated separately for hunger, fullness, desire to eat and prospective consumption. These domains are related, but they are not interchangeable: a result for one question would not by itself establish the result for another. The registry record does not identify a single comparison that represents all four questions.

How should least-squares means and standard errors be read?

The registry identifies the reported summary as a least-squares mean and its dispersion as a standard error. In general, a least-squares mean is a model-based mean, often adjusted for terms included in the statistical model. Its interpretation depends on the model and covariates. The specific model, adjustments and estimated contrasts are not reported in the registry record.

A standard error represents uncertainty in an estimated mean. It is not the same as a standard deviation, which describes variation among individual observations. Standard errors can help readers judge the precision of an estimate, but they do not give a complete account of uncertainty without the estimate and an inferential procedure such as a confidence interval or test. Those comparative results are not reported in the registry record for a single primary endpoint contrast.

What does crossover design imply?

In general, a crossover design has participants receive more than one intervention, so comparisons can use information from within the same person. This may reduce the influence of stable differences between participants. The registry identifies the model as crossover, but does not report the treatment sequences, visit schedule, washout arrangements or the specific statistical handling of repeated observations. It is therefore not possible to assess from the registry record whether period effects, sequence effects or possible carryover were considered in the analysis.

Randomization is reported, but the method used to generate the sequence and how allocation was implemented are not reported in the registry record. The study is marked single-masked, but the record does not identify who was masked. These details matter when assessing how allocation and knowledge of treatment could affect measurement or analysis; their absence should be treated as uncertainty about reporting, not as evidence that a particular procedure was or was not used.

Why does the reporting structure matter?

The primary outcome includes four appetite questions and repeated measurements over time. Reporting several domains and time points creates a need to define which outcomes and comparisons are primary and how inference across them is handled. In general, testing multiple outcomes can increase the chance of at least one apparently unusual result if no adjustment or hierarchy is specified. The registry record does not report a multiplicity strategy or a single result that resolves the several endpoint categories and time points.

The registry lists 4 outcome measures and 3 analyses, but the information does not identify a complete statistical analysis plan. The exact model, contrast definitions, missing-data procedures and analysis populations are not reported in the registry record. Without these details, readers cannot determine whether the estimates would be adjusted, how participants with incomplete measurements would be handled, or whether all planned analyses are represented.

General statistical interpretation should also distinguish an estimate from its precision and from its practical meaning. A point estimate describes the fitted result, while an interval or standard error expresses uncertainty. Neither alone determines whether a difference matters outside the statistical model. In this case, the primary comparative estimates are not reported in a form that permits such an assessment.

10. Multiplicity, Missing Data and Analysis Populations

The primary endpoint covers four appetite domains: hunger, fullness, desire to eat and prospective consumption. Each was assessed repeatedly over the post-snack period. The registry record states that the primary outcome has several categories or time points and was not reduced to one comparison. It does not report a hierarchy among the domains, a designated primary contrast, or a procedure for addressing multiplicity. In general, when analyses consider multiple outcomes or comparisons, a prespecified strategy helps clarify which findings are confirmatory and how uncertainty should be interpreted.

The record lists 4 outcome measures and 3 analyses, but this information does not specify the full analysis plan. The model terms, contrast definitions, any adjustment for multiple comparisons, and the handling of repeated ratings are not reported in the registry record. No single primary comparison is available for interpretation.

Missing-data methods are not reported in the registry record. The record gives enrollment counts but does not state how many participants completed each study, contributed ratings at each time point, or were included in each endpoint analysis. It also does not describe how missed visits, incomplete VAS responses or withdrawals were handled. Thus, the enrollment counts should not be read as analysis denominators.

The analysis population is also not reported in the registry record. In a crossover study, defining which participants and periods contribute to each comparison is important, but the specific population used for the analyses cannot be determined from the available registry description. These reporting gaps limit assessment of the completeness and precision of the primary outcome results.

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 a Seed Study and a Pita Study safety group. For each, 38 participants are recorded as at risk in the serious adverse event category and 0 as affected. The other adverse event category also lists 38 at risk and 0 affected in each study. Deaths are recorded as 0 in both groups, and no serious adverse event terms are listed.

These are registry counts, not comparative estimates. The record does not report a treatment-specific breakdown of the counts or a detailed account of safety monitoring and event collection. The counts therefore should be read as the events entered for these categories in the registry record, not as proof that no event of any kind occurred. They also do not establish comparative safety between interventions. The observation period and analysis population for these safety entries are not reported in the registry record.

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

The registry record establishes that the trial assessed appetite ratings after snack interventions using repeated VAS measurements and an area-under-the-curve endpoint. It also documents randomized, single-masked, crossover design features, enrollment across the Seed and Pita studies, and safety entries showing zero recorded serious adverse events, other adverse events and deaths for each study group.

It does not establish whether the snack conditions differed in hunger, fullness, desire to eat or prospective consumption. The primary outcome encompasses multiple categories and time points, and the record does not reduce it to one comparison. Comparative estimates, their standard errors and confidence intervals are not reported in the registry record in a form that allows the size, direction or precision of a primary contrast to be assessed. No conclusion about the presence or absence of an appetite effect should be drawn from enrollment and endpoint descriptions alone.

In general, a treatment estimate describes the observed contrast under a specified analysis, while its uncertainty indicates how precisely that contrast was estimated. Practical interpretation also depends on the outcome scale and the relevance of the size of the difference. Because the primary comparative results and the model details are not reported in the registry record, these dimensions cannot be evaluated from the posted information.

The safety entries likewise have a limited scope. Recorded zero counts do not demonstrate the absence of every possible adverse event, nor do they compare event risk across specific snack interventions. The record describes a study of appetite measures in healthy Canadians; it does not report evidence that can be generalized beyond the study population or used to make clinical recommendations.

13. Why This Trial Matters Statistically

This trial illustrates how a registry can describe a measurement strategy without making the primary comparison interpretable. Repeated VAS ratings were collected across a defined post-snack period and summarized as area under the curve. That approach can capture a pattern over time, but it produces separate measures for distinct appetite questions. Clear reporting of the prespecified outcome, contrast and uncertainty is essential when an endpoint contains several domains and repeated observations.

The crossover design also highlights the importance of transparent methods reporting. In general, within-participant comparisons can account for stable differences among participants, but interpretation depends on the treatment sequence, timing, period effects and analytic model. The registry identifies the design as crossover without documenting those details. Readers therefore cannot assess how the design features were incorporated into the analysis.

Enrollment counts are useful for describing recruitment, but they are not a substitute for outcome-specific denominators. The record reports 46 participants overall, with 38 enrolled in each study, yet does not report the number contributing to each primary outcome analysis. Reporting those denominators alongside estimates and measures of uncertainty would help readers assess the completeness and precision of the results.

The safety entries show the value of separating recorded event counts from conclusions about comparative risk. Zero recorded counts are informative as registry entries, but without fuller event definitions, observation details and treatment-specific comparisons, they do not answer every safety question. Together, these reporting issues make the trial a useful example of why design, endpoint definition, analysis details and complete comparative results all matter when interpreting clinical research.

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 principal limitation for interpreting the primary endpoint is that the registry record does not report a single comparison across its multiple appetite categories and time points. It describes the measurement process and the summary statistic, but not comparative estimates or their uncertainty. As a result, the direction, size and precision of any difference between conditions cannot be assessed from the primary outcome information.

The methods description is incomplete for evaluating a crossover analysis. The treatment sequence, timing between interventions, washout arrangements, identity of the masked party and details of the statistical model are not reported in the registry record. It is also not clear how period or sequence effects were addressed, if relevant to the analysis.

Enrollment is reported, but analysis denominators, completion by study, missing-data handling and analysis populations are not reported in the registry record. The endpoint includes multiple appetite domains, yet the record does not describe a multiplicity strategy or specify one comparison that resolves them. The listed secondary outcome is calories consumed post-snack until bedtime, but comparative results for that outcome are not described in the registry record.

Some intervention descriptions are incomplete. The full composition of each comparator and snack cannot be established from the registry record, and the arm descriptions do not provide a complete account of every intervention. The safety entries are limited to registry counts and do not provide detailed event definitions, follow-up information or treatment-specific comparative estimates. These limitations restrict interpretation of the posted information; they do not establish that unreported procedures or analyses were absent from the conduct of the trial.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effect of Snacks on Appetite Control — NCT01806688.
• Registry record last updated 2021-08-12; status last verified 2021-08.
• Results first posted 2021-08-12.
• 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 record describes NCT01806688, a completed randomized, single-masked crossover study titled “Effect of Snacks on Appetite Control.” It enrolled 46 participants overall; 30 participated in both the Seed Study and the Pita Study, and 16 enrolled in just one. The record reports 38 participants enrolled in each study.

The primary outcome was total area under the curve for hunger, fullness, desire to eat and prospective consumption, assessed with VAS ratings before a snack and every 30 minutes after the first bite up to 180 minutes. Ratings were integrated using the trapezoid method. The record does not reduce the multiple endpoint categories and time points to one primary comparison or report comparative estimates for that outcome.

For each study, the registry lists 0 serious adverse events, 0 other adverse events and 0 deaths. The primary outcome analysis details, missing-data handling, analysis populations and multiplicity approach are not reported in the registry record.