Overall reviewer summary

The manuscript addresses an important public health issue: processed food consumption, body image perception, and lifestyle changes among university students during the COVID-19 pandemic. However, the paper requires substantial revision before it can be considered scientifically sound. The main concern is that the study appears to measure perceived body image, not actual overweight or obesity based on anthropometric assessment. Therefore, the title, objective, abstract, results, and discussion should avoid implying that participants were objectively overweight or obese.

There are also inconsistencies in the reported sample size, with the abstract mentioning 82 students, the methods mentioning 84 students, and Table 1 showing N = 82. Several statistical methods appear inappropriate for the data structure, and some p-values reported in the text do not match the table. These issues should be corrected carefully.

I recommend rejection/not approval in the current form. The manuscript addresses a relevant topic, but major methodological and statistical issues limit confidence in the findings. In particular, the statistical tests reported appear inappropriate for the data structure, including the use of Pearson correlation for categorical/ordinal variables and paired t-test for gender comparisons involving independent groups. These issues may invalidate the reported associations. The manuscript also lacks a clear sample size justification, has inconsistent sample size reporting, provides insufficient explanation of recruitment and data collection procedures, and interprets perceived body image as overweight/obesity without objective anthropometric assessment. A full methodological revision and statistical re-analysis are required before the manuscript can be reconsidered.

1. Title

Current issue:

The title says students who “perceive themselves as overweight and obese tend to have higher consumption of processed foods.” This is closer to the study measurement, but the wording still risks implying actual overweight/obesity.

Suggested comment to author:

The title should be revised to clearly reflect that the outcome is perceived body image, not objectively measured overweight or obesity. Since no BMI, body weight, height, or anthropometric data appear to have been collected, the manuscript should avoid using “overweight” and “obesity” as if they were measured nutritional status categories.

Possible revised title:

“Processed food consumption and perceived body image among Peruvian university students during the COVID-19 pandemic: an observational study”

2. Abstract

The abstract has several inconsistencies and overstatements. The Methods section states that the study included 82 students, but the Results section states 84 students. This must be corrected. Also, the objective says the study aimed to determine the relationship between processed foods and “being overweight,” but the actual measurement was body image perception using silhouettes, not measured overweight/obesity.

The abstract should be revised for accuracy and consistency. The authors should clarify whether the final sample size was 82 or 84, as different numbers are reported in the abstract, methods, results, and Table 1. The objective should also be rephrased to reflect the actual outcome measured, namely perceived body image, rather than actual overweight or obesity. In addition, the conclusion should be more cautious because this observational cross-sectional study cannot establish causality.

The abstract reports that females more frequently perceived themselves as overweight and had higher processed food consumption, and that processed food consumption was related to overweight/obesity. However, these claims are not supported with quantitative results in the abstract. The authors should report the relevant percentages, statistical tests, p-values, and, where possible, measures of association. The term “perceived overweight/obesity” should also be used consistently.

3. Introduction

The introduction gives useful background on COVID-19, lifestyle changes, processed food consumption, and overweight/obesity. However, the introduction is too broad and does not clearly lead to the specific research gap. It discusses COVID-19, obesity, processed foods, physical activity, and chronic disease, but the link to body image perception among university students in Peru needs to be developed more clearly.

The Introduction should be strengthened by clearly identifying the research gap. The authors should explain why body image perception is important in this context and why it is relevant to examine perceived overweight/obesity rather than measured BMI. The distinction between processed foods, highly processed foods, and ultra-processed foods should also be clarified, as these terms appear to be used interchangeably in the manuscript.

The objective at the end of the Introduction says the study aims to determine the relationship between processed foods and “perception of changes in body image.” However, the Methods describe measurement of body image perception using the Thompson and Gray Scale. These are not exactly the same. The authors should clarify whether they assessed:

current perceived body image,

4. Methods

This section contains several details that are not directly relevant to the study methodology, such as descriptions of Canva, Office, Jamboard, and digital whiteboards. These details should be removed or shortened. The section should instead clearly describe the observational design, study setting, study period, participant population, and recruitment/data collection procedures.

The manuscript states that “snowball sampling was used for simple random sampling.” This is contradictory. Snowball sampling is a non-probability sampling method, while simple random sampling is probability-based.

The participant recruitment and data collection procedures need to be described more clearly. It is currently unclear whether the questionnaire was administered face-to-face, online, or using a hybrid approach, and whether it was self-administered or interviewer administered. Although the manuscript mentions recruitment through social networks and the university website, it also states that printed informed consent was obtained and that surveys were conducted in person. These details should be reconciled and explained in a clear chronological sequence.

Figure 1 is also confusing and insufficiently explained in the text. The flowchart shows several numbers, including target population, voluntary recruitment, total sample, inclusion criteria, shortlisted participants, exclusion criteria, and final enrolment, but the meaning of each step is not clearly described. The authors should explain how the number of participants changed from the target population to the final analytical sample, including how many students were screened, excluded, and analysed, with reasons for exclusion.

The authors should also clarify whether “face-to-face and remote classes” refers only to the students’ learning experience as an inclusion criterion, or whether it refers to the mode of data collection. At present, this distinction is unclear and may confuse readers.

The authors should provide a sample size calculation or justification for the final sample size. At present, it is unclear how the minimum required sample size was determined and whether 84 participants are sufficient to address the study objectives. This is particularly important because the study setting is described as the largest university in Peru, with more than 150,000 students. Without an appropriate sample size calculation and sampling strategy, the representativeness and generalisability of the findings are limited.

4.2 Sample size inconsistency

The paper reports several different sample sizes:

Section

Reported sample

Abstract Methods

82

Abstract Results

84

Methods

84

Table 1

N = 82

Gender total in Table 1

52 + 30 = 82

Flowchart

Enrolled = 84

Suggested reviewer comment:

The final analytical sample size must be corrected and reported consistently throughout the manuscript. The flowchart, abstract, methods, results, and tables should all use the same final sample size. If two participants were excluded from some analyses due to missing data, this should be clearly explained.

4.3 Instruments

The authors state that they used a questionnaire based on the sQ-HPF. However, it is unclear whether the adapted questionnaire was validated for this study population.

The authors should provide more details on the adaptation and validation of the processed food consumption questionnaire. They should report whether the Spanish version used in this study had been validated, whether any pilot testing was conducted, and whether reliability statistics were calculated.

The Thompson and Gray Scale assesses perceived body image using silhouettes. This is acceptable, but the authors should be careful not to interpret it as actual BMI or nutritional status.

The authors should clearly state that the Thompson and Gray Scale measures perceived body image only. The terms “overweight” and “obesity” should be consistently qualified as “perceived overweight” and “perceived obesity” unless anthropometric measurements were collected.

4.4 Variables

The Results mention physical exercise and perceived weight variation, but these variables are not clearly described in the Methods.

The Methods should clearly define all variables analysed, including perceived weight variation and physical exercise. The authors should explain how these variables were measured, coded, and analysed.

4.5 Statistical analysis

Major issue. Some statistical tests appear inappropriate. For example, the authors report using Pearson correlation for variables that appear to be ordinal/categorical. They also mention a paired t-test for gender differences, but gender groups are independent, not paired.

The statistical analysis section should be revised. Since most variables are categorical or ordinal, the authors should consider using chi-square tests, Fisher’s exact tests, Spearman correlation, Mann–Whitney U tests, Kruskal–Wallis tests, or ordinal/logistic regression where appropriate. The use of paired t-tests for gender comparisons is inappropriate unless the data are paired, which does not appear to be the case. The authors should also report effect sizes and confidence intervals, not only p-values.

Given the small sample size and multiple food categories tested, the authors should address multiple comparisons and the risk of type I error.

5. Results

Table 1 reports N = 82, but the manuscript elsewhere reports 84. Also, the percentage for Engineering students appears incorrect: 11 students cannot be 1.2% of the sample; it should be approximately 13.4% if N = 82.

The authors should carefully check all frequencies and percentages in Table 1. The percentage for Engineering students appears to be incorrect. The statement that there was a “significant difference” in age between women and men is also incorrect because p = 0.304 indicates no statistically significant difference.

Major issue:

Some p-values reported in the text do not appear to match Table 2. For example, the text reports associations for fast food and sweets, but Table 2 shows different p-values.

The authors should cross-check all p-values reported in the Results against the tables. Any discrepancy between the text and tables must be corrected. The Results should report only statistically supported findings.

On page 8, part of the Results appears to be repeated almost verbatim.

The Results section contains repeated text regarding processed food consumption patterns among overweight men, obese women, perceived weight variation, and physical exercise. This should be edited to avoid redundancy.

5.4 Interpretation of body image categories

The Results repeatedly describe students as overweight or obese, but this is based on silhouette perception.

Throughout the Results, the authors should consistently use “perceived overweight” and “perceived obesity” rather than implying measured weight status.

6. Tables and Figure

Table 1 needs correction due to the inconsistent N and incorrect percentage for Engineering students. The authors should also consider presenting the sample characteristics more cleanly.

Table 2 is very long and difficult to follow. The authors may consider simplifying the table by grouping “frequent” and “very frequent” consumption, if statistically justified, or presenting only the most relevant food categories in the main text and moving the full table to supplementary material.

Figure 2 is visually interesting, but it is not fully clear how the percentages were calculated. The legend also uses “Appetizers,” while the Methods mention “snacks.” The terminology should be harmonised. The figure caption should explain whether the percentages represent frequent plus very frequent consumption, and whether they are stratified by gender or body image category.

7. Discussion

The Discussion sometimes overstates the findings. The study is cross-sectional, small, and based on self-reported perceived body image. Therefore, the authors should not imply that processed food consumption caused overweight/obesity or that participants were objectively overweight/obese.

The Discussion should be revised to avoid causal language. The authors should interpret the findings as associations between processed food consumption and perceived body image. They should also discuss alternative explanations, including body image dissatisfaction, emotional eating, self-report bias, selection bias, and reverse causality.

The biggest limitation is that actual anthropometric data were not collected. This should be clearly acknowledged.

The Discussion uses the word “cohort,” but this is not a cohort study. It is observational and cross-sectional. Replace “cohort” with “sample” or “group of university students.”

8. Conclusion

The conclusion is generally aligned with the findings but should be more cautious.

The conclusion should be revised to clearly state that processed food consumption was associated with perceived overweight/obesity, not objectively measured overweight/obesity. The authors should avoid implying causality and should highlight the need for future studies using measured anthropometry, larger samples, and longitudinal designs.

9. Ethical and reporting issues

The ethical information appears twice: once in Methods and again after the conclusion. This creates repetition.

The author contribution section includes initials that do not appear to match the listed authors, such as M.E.M-M. and N.A.B.C. This should be checked carefully.

Is the work clearly and accurately presented and does it cite the current literature?

Partly

If applicable, is the statistical analysis and its interpretation appropriate?

No

Are all the source data underlying the results available to ensure full reproducibility?

Partly

Is the study design appropriate and is the work technically sound?

Partly

Are the conclusions drawn adequately supported by the results?

Yes

Are sufficient details of methods and analysis provided to allow replication by others?

Partly

Reviewer Expertise:

Ultra-processed food

I confirm that I have read this submission and believe that I have an appropriate level of expertise to state that I do not consider it to be of an acceptable scientific standard, for reasons outlined above.