Energy Expenditure Exceeds Nutritional Intake of ROTC Members During a Field Training Exercise

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Energy Expenditure Exceeds Nutritional Intake of ROTC Members During a Field Training Exercise

Authors' explore a pressing topic relating to ROTC cadets' energy levels and how their body takes macronutrients during a field exercise. This study is surely relevant to JFMK's readers because it examines how shape, movement and performance clash while completing grueling physical tasks. The research plan is fitting for observation and the report is good, on the whole.

The core result which shows big energy shortages and unhealthy ratios of macronutrients, carbs and protein in short FTXs—was crystal clear and follows what others found in both military units and among athletes. This work high lights an important detail for military prep.

But the paper need major revisions before consider publishing. Some major areas needing work include the need for better conversation, discussing limitations in methods mainly how energy burns were measured and food diaries kept. Second point data presented in tables and figures could be clearer and it is also inconsistent sometimes. And finally the discussion should tie its finding to actual solutions based on the proof, also it must use latest findings.

Major comments

Introduction:

Nutrition's importance for military personnel is smartly set up within the introduction; the MDRI guidelines are nicely outlined too.

Suggestion: Maybe bring up early difficulties with self-reported dietary intake in field settings to better shape those methods maybe?

Materials & Methods

2.2 Participants: The demographic info is clear, ya know? They noted 14 were out. That flow diagram (Figure 2) does a great job but the caption... it should just state exactly why they're excluded such as like "didn't finish FTX" or "Not enough nutrition stuff". Get me?

2.3 Participant Data Collection:

Using ComRAD plus USDA FoodData Central is a good move I reckon.

Major problem: Energy expenditure. Relying on those wrist accelerometers without taking load stuff (like rucksacks) into the mix is a big deal limitation. Though the authors nail it in their limitations part. The Methods section however really should admit the issues earlier and explain the decision behind it. And yeah maybe cite some study that looks at trouble estimating EE with accelerometry when hauling stuff around.

The LEA explanation? Good. BUT the line: "The International Olympic Committee provides LEA standards as males consuming less than 9-25 kcal/kg/FFM/day". Sounds off, like a typo, maybe?

Alright, here we go: That lower limit of 9 kcal/kg/FFM, for the males, it just seems crazy low, and doesn't mesh with that Mountjoy et al. paper, from 2023. Can someone please double check these values and fix it?

Results

The findings, by and large, are quite plain and back up the final points, ya know?

Problems in the Tables and Figures:

Table 2/4 is messed up. Somethings gone wrong with the labels. The table found in the result section, that's on page 8, it's called "Table 4." This needs a fix, so its table 2, and keeps everything flowing.

Figure 4, its labels for the female graph are not clear at all. I think the numbers read like 0, 100, 200, 300, and 400. but, that "800" is out of place, surely, its a mistake. Gotta fix it! also the figure description, should spell out exactly what the center line of the box plots is (the median), plus what the whiskers indicate.

Discussion

The discussion does a solid job explaining the main stuff like energy deficit and LEA, got it?

Improving the Argument: The paragraph talking about handy recommendations, that's on page 11, that's a good move. But to make it stronger, consider adding specific references to back these up. Like this:

Protein shakes: The McAdam et al. , 2018 is great, use it, i think so.

For loading carbs and protein before the race, try citing a review focused on nutritional tactics for endurance.

Alright, here is the text with the requested modifications:

Contextualizing Energy Expenditure: Indeed, the measured EE, it was lower than what some prior studies showed. The explanation they gave is fine, but it really needs to link back to the limitations of the accelerometry. That lower-than-expected EE, well, it could be the accelerometer's fault, failing to completely catch the metabolic price of those loaded marches plus military-specific tasks.

Clarity on LEA Thresholds: Lets look at the LEA threshold discussion (page 10). "Fell below the IOC's LEA threshold defined as <30 kcal/kg FFM per day for females and <25 kcal/kg FFM/day for males" it's clearer now than what's in the Methods section, still, the differences gotta be cleared up.

Limitations

The limitations section? It is comprehensive and really well written. It's properly covers self-reporting bias, plus those accelerometry limitations, and that short study length. The point about heart rate variability, it’s great, a key rec' for future studies.

Conclusions

The conclusions they make are well supported by the data, which summarizes the implications so clearly.

Typos and Minor Corrections

Page 1, Correspondence: The email listed is jms0018@aburn edu; tho, it should probably be jms0018@auburn edu.

Page 6, Equation E(nergy)B(alance) = N(utritional)I(ntake) - E(nergy)E(xpenditure) - That "Intake" spelling in the abbreviation, well, it’s off.

Across the whole piece make sure that you use those spaces around statistical numbers, you know like p < 0. 001.

This paper tackles an important research question, it does, using a solid, sound method for this observational study. The heart of the findings there are valuable, showing a real, definite problem in how the military trains. Some serious revisions are needed, but ya they're totally doable. if the authors address the methodology gaps in detail, and fix the tables and figures - presentation blunders - along with a better discussion incorporating a focused set of references, well, the impact of their work and how rigorous it is will jump up a lot.

Author Response

 We Would like to thank you for the review of the manuscript and for your feedback for the suggested changes.

Reviewer 1

Comments and Suggestions for Authors

Energy Expenditure Exceeds Nutritional Intake of ROTC Members During a Field Training Exercise - Manuscript ID jfmk-3998066

Authors' explore a pressing topic relating to ROTC cadets' energy levels and how their body takes macronutrients during a field exercise. This study is surely relevant to JFMK's readers because it examines how shape, movement and performance clash while completing grueling physical tasks. The research plan is fitting for observation and the report is good, on the whole.

The core result which shows big energy shortages and unhealthy ratios of macronutrients, carbs and protein in short FTXs—was crystal clear and follows what others found in both military units and among athletes. This work high lights an important detail for military prep.

But the paper need major revisions before consider publishing. Some major areas needing work include the need for better conversation, discussing limitations in methods mainly how energy burns were measured and food diaries kept. Second point data presented in tables and figures could be clearer and it is also inconsistent sometimes. And finally the discussion should tie its finding to actual solutions based on the proof, also it must use latest findings.

Thank you for your considerations and recommendations. Please see the bolded text for our responses to your comments and changes to the manuscript.

Major comments

Introduction:

Nutrition's importance for military personnel is smartly set up within the introduction; the MDRI guidelines are nicely outlined too.
  Thank you

Suggestion: Maybe bring up early difficulties with self-reported dietary intake in field settings to better shape those methods maybe?

As structured, this is one of the most accurate ways that self-reporting of nutritional intake in a field setting can be completed. This is also addressed in the limitations of the inherent nature of self-reported nutritional intake.

Materials & Methods

2.2 Participants: The demographic info is clear, ya know? They noted 14 were out. That flow diagram (Figure 2) does a great job but the caption... it should just state exactly why they're excluded such as like "didn't finish FTX" or "Not enough nutrition stuff". Get me?

Thank you for your recommendation. We feel that the explanations of why cadets were removed from the study are adequately explained in Figure 2 for the participant flow and sample size as outlined in the righthand column of why the participants were removed with the number “n” falling into that category and when they were removed from the study. This information is in the diagram as required, not the caption to avoid redundancy of information in the manuscript per typical academic journal recommendations.

2.3 Participant Data Collection:

Using ComRAD plus USDA FoodData Central is a good move I reckon.

Thank you.

Major problem: Energy expenditure. Relying on those wrist accelerometers without taking load stuff (like rucksacks) into the mix is a big deal limitation. Though the authors nail it in their limitations part. The Methods section however really should admit the issues earlier and explain the decision behind it. And yeah maybe cite some study that looks at trouble estimating EE with accelerometry when hauling stuff around.

Thank you for your comment. If you are unfamiliar with accelerometer use, particularly in field research, you are unable to change values while you are in the field to adjust for donning and doffing extra weight / rucks/ etc. While this is a limitation of the study many previous studies have conducted similar research and list this as a limitation.

Horner, Fleur, et al. "Development of an accelerometer-based multivariate model to predict free-living energy expenditure in a large military cohort." Journal of Sports Sciences 31.4 (2013): 354-360.

Lin, David J., et al. "Predicting soldier performance on structured military training marches with wearable accelerometer and physiological data." IEEE Sensors Journal 24.1 (2023): 403-413.

Linssen, Lotte, et al. "Using accelerometry and heart rate data for real-time monitoring of soldiers’ stress in a dynamic military virtual reality scenario." Multimedia Tools and Applications 81.17 (2022): 24739-24756.

The LEA explanation? Good. BUT the line: "The International Olympic Committee provides LEA standards as males consuming less than 9-25 kcal/kg/FFM/day". Sounds off, like a typo, maybe?

Thank you for your concern, however, this is reported in the 2023 IOC consensus statement of Relative Energy Deficiency in Sports. Stating:

“While a universal cut-off of 30 kcal/kg FFM/day as a threshold of LEA leading to some REDs outcomes in females is debated, such a cut-off or range at which males experience REDs-related symptoms is even less understood, but appears to be lower (eg ~9-25 kcal/kg FFM/day). 
  
This statement can be found on page 1077 of the article, in the beginning of the 2^nd paragraph under “REDs in male athletes”

Mountjoy, Margo, et al. "2023 International Olympic Committee’s (IOC) consensus statement on relative energy deficiency in sport (REDs)." British journal of sports medicine 57.17 (2023): 1073-1098.

Alright, here we go: That lower limit of 9 kcal/kg/FFM, for the males, it just seems crazy low, and doesn't mesh with that Mountjoy et al. paper, from 2023. Can someone please double check these values and fix it?

Please see the above comment.

Results

The findings, by and large, are quite plain and back up the final points, ya know?

Thank you

Problems in the Tables and Figures:

Table 2/4 is messed up. Somethings gone wrong with the labels. The table found in the result section, that's on page 8, it's called "Table 4." This needs a fix, so its table 2, and keeps everything flowing.

Thank you for recognition of our oversight during edits. This has been adjusted.

Figure 4, its labels for the female graph are not clear at all. I think the numbers read like 0, 100, 200, 300, and 400. but, that "800" is out of place, surely, its a mistake. Gotta fix it! also the figure description, should spell out exactly what the center line of the box plots is (the median), plus what the whiskers indicate.

Thank you for your comment on Figure 4. We are unaware the location that you see “800”. Looking at the figure for Female ROTC Nutritional intake the axis reads “0, 100,200,300,400,500” With additional lines to indicate spaces of 25.
  We have added in the description of the middle line of the plot (the mean). There are no whiskers on the figure. These are individual data points and we have included this in the Figure description per academic journal guidelines.

Discussion

The discussion does a solid job explaining the main stuff like energy deficit and LEA, got it?

Thank you

Improving the Argument: The paragraph talking about handy recommendations, that's on page 11, that's a good move. But to make it stronger, consider adding specific references to back these up. Like this:

Protein shakes: The McAdam et al. , 2018 is great, use it, i think so.

Thank you, this is in the manuscript in line 395-396.

For loading carbs and protein before the race, try citing a review focused on nutritional tactics for endurance.

We have included an additional citation regarding these. Line 388-391.

Alright, here is the text with the requested modifications:

Contextualizing Energy Expenditure: Indeed, the measured EE, it was lower than what some prior studies showed. The explanation they gave is fine, but it really needs to link back to the limitations of the accelerometry. That lower-than-expected EE, well, it could be the accelerometer's fault, failing to completely catch the metabolic price of those loaded marches plus military-specific tasks.

We agree with this concern and it is why we have addressed it in the limitations of the study as well as in the discussion of the study.

Clarity on LEA Thresholds: Lets look at the LEA threshold discussion (page 10). "Fell below the IOC's LEA threshold defined as <30 kcal/kg FFM per day for females and <25 kcal/kg FFM/day for males" it's clearer now than what's in the Methods section, still, the differences gotta be cleared up. -

We understand the confusion and have provided a more detailed explanation that we used the LEA standard of <25 kcal.kg FFM/day for the calculations of this study.  Line 202 -203.

Limitations

The limitations section? It is comprehensive and really well written. It's properly covers self-reporting bias, plus those accelerometry limitations, and that short study length. The point about heart rate variability, it’s great, a key rec' for future studies.

Thank you 

Conclusions

The conclusions they make are well supported by the data, which summarizes the implications so clearly.

Thank you.

Typos and Minor Corrections

Page 1, Correspondence: The email listed is jms0018@aburn edu; tho, it should probably be jms0018@auburn edu.

Thank you for this find. We have corrected it in the manuscript.

Page 6, Equation E(nergy)B(alance) = N(utritional)I(ntake) - E(nergy)E(xpenditure) - That "Intake" spelling in the abbreviation, well, it’s off.

We have added additional spaces between the words to improve clarity of this equation.

Across the whole piece make sure that you use those spaces around statistical numbers, you know like p < 0. 001.

 We have reviewed the manuscript to ensure these spaces.

This paper tackles an important research question, it does, using a solid, sound method for this observational study. The heart of the findings there are valuable, showing a real, definite problem in how the military trains. Some serious revisions are needed, but ya they're totally doable. if the authors address the methodology gaps in detail, and fix the tables and figures - presentation blunders - along with a better discussion incorporating a focused set of references, well, the impact of their work and how rigorous it is will jump up a lot.

Thank you for your comments and suggestions to improve our manuscript.

Reviewer 2 Report

Comments and Suggestions for Authors

The topic of the manuscript is important, the aim of the study is understandable, and important.

The description of the study protocol is understandable/linear, but raises some questions:

• Fig 1 shows the study protocol. In this manuscript only parts of the complex study are shown, but why? If there were blood tests/urine collection, some parameters/data should be correlated with the Energy Expenditure, the obtained data of CH, protein, fat consumption, even if it is based on self reports.
• How was body composition measured? How was fat percentage of subjects computed?

Fat percentage of female subjects seems to be high, they might be overweight in average, while male subjects are falling mainly into the normal range in this respect. Energy balance, metabolism during exercises is very different in the normal and in the overweight population. Authors report a low Energy intake, and a big physical demand. Did the weight of subjects change within the 2-3 days field protocol?

Activity was measured with ActiGraph. Based on many factors, this device is capable of calculating the ratio/time spent in low-, moderate, or high intensity exercises. This way the collected data would help to further analyze the correlation between intensity and Energy need, since indeed the load one carries during the 6 mile ruck, would change physiological/metabolic needs of subjects.

The Results section needs a lot of improvement.

• I did not find Table 2 and Table 3.
• Authors refer to Fig 3 only in Discussion, nothing is written about it in this section.
• - Table 4 and Fig 4 should be explained better in the Results.

Discussion is well written, more detailed but some above mentioned data should be considered also. After writing about missing parts already in Materials and Methods, data obtained and included in Results, should be discussed also.

The referred scientific manuscripts and data are relevant and important in the text.

As suggest major revision of the manuscript.

Author Response

We Would like to thank you for the review of the manuscript and for your feedback for the suggested changes.

Energy Expenditure Exceeds Nutritional Intake of ROTC Members During a Field Training Exercise - Manuscript ID jfmk-3998066

Reviewer 2

Comments and Suggestions for Authors

The topic of the manuscript is important, the aim of the study is understandable, and important.

Thank you.

The description of the study protocol is understandable/linear, but raises some questions:

• Fig 1 shows the study protocol. In this manuscript only parts of the complex study are shown, but why? If there were blood tests/urine collection, some parameters/data should be correlated with the Energy Expenditure, the obtained data of CH, protein, fat consumption, even if it is based on self reports.

We have revised Figure 2 to more adequately represent the current study and outcomes investigated rather than have the entire study protocol.

• How was body composition measured? How was fat percentage of subjects computed?

Thank you for your notification of this vast oversight. We have re-written the baseline testing procedures and added it into the manuscript under “2.3 Participant Data Collection.”

Fat percentage of female subjects seems to be high, they might be overweight in average, while male subjects are falling mainly into the normal range in this respect. Energy balance, metabolism during exercises is very different in the normal and in the overweight population. Authors report a low Energy intake, and a big physical demand. Did the weight of subjects change within the 2-3 days field protocol?

               We did not complete weight and body composition measures post -FTX. Due to the short time period of the FTX we believed any changes were likely due to hydration status or “water weight” / sweat rates/ acute muscle damage and inflammatory factors, etc. We have included this in the limitations and future directions of the manuscript.

Activity was measured with ActiGraph. Based on many factors, this device is capable of calculating the ratio/time spent in low-, moderate, or high intensity exercises. This way the collected data would help to further analyze the correlation between intensity and Energy need, since indeed the load one carries during the 6 mile ruck, would change physiological/metabolic needs of subjects.

 Thank you, we did initially consider this. Due to the observational nature of the study, and that we could not adequately monitor all groups during their activities, our team member with the most experience and familiarity with accelerometry data recommended that we focus on the overall picture as there were multiple groups completing many tasks at different venues. Because some of these tasks might be more loaded and difficult with only minor movements, this has the potential to offset the data gathered from the accelerometer.

The Results section needs a lot of improvement.

• I did not find Table 2 and Table 3.
  Thank you for your recognition of this. We have corrected this oversight that we missed in our editing process.
• Authors refer to Fig 3 only in Discussion, nothing is written about it in this section.

We have incorporated references to Figure 3 in the results section.

• - Table 4 and Fig 4 should be explained better in the Results.

Thank you, we have incorporated additional information and discussion regarding these figures; Lines 255- 261 and lines 280 – 289.

Discussion is well written, more detailed but some above mentioned data should be considered also. After writing about missing parts already in Materials and Methods, data obtained and included in Results, should be discussed also.

Thank you, we have included this information in the manuscript.

The referred scientific manuscripts and data are relevant and important in the text.

Thank you.

As suggest major revision of the manuscript.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

No more comments to add.