Cold ExposureNCT07489690
Energy Dense Fueling for Cold-Weather Operations
A study testing High Fat and High Carbohydrate in people with Cold Exposure, run by United States Army Research Institute of Environmental Medicine at 1 site in United States.
Trial summary
High daily energy expenditures without compensatory increases in energy intakes results in severe energy deficits during cold-weather military operations. Observational and experimental data from our laboratory suggests that consuming higher-fat, energy dense products can increase energy intake and attenuate energy… Read more about this study
- Who is it for?
- Ages 18 to 39 yearsHealthy volunteers can take part
- Conditions the study is for
- Cold Exposure
- What is being tested?
- High Fat and High Carbohydrate
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 8 participants
- Where
- 1 siteUnited States
- Study dates
- 14 Feb 2026to 30 Sep 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 39 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
None listed.
Who cannot join
- Metabolic or cardiovascular abnormalities, gastrointestinal disorders (i.e., kidney disease, diabetes, cardiovascular disease, hypertension etc.) that is unsuitable for the study determined by OMSO
- Disease or medication (i.e., diabetes medications, statins, corticosteroids, etc) that affects macronutrient utilization and/or the ability to participate in strenuous exercise
- Allergies or intolerance to foods (including but not limited to lactose intolerance/milk allergy), vegetarian practices
- Present condition of alcoholism, anabolic steroids (testosterone, enanthate, undecanoate, etc), or other substance abuse issues
- Unwilling to stop use of nutritional/sports supplements (creatine, multivitamins, whey etc.) while enrolled in the study
- Sensitivity to medical adhesives resulting in significant skin irritation
Show all 15Show fewer
- Acute or chronic musculoskeletal injury that compromises the ability to run and ruck march
- History of disease of the gastrointestinal tract including (but not limited to) diverticulosis, diverticulitis and inflammatory bowel disease, peptic ulcer disease, Crohn's disease, ulcerative colitis; or previous gastrointestinal surgery
- Difficulty swallowing large pills or unwilling to insert rectal temperature sensor
- Raynaud's syndrome.
- History of cold injuries of any severity (e.g., frostbite, trench foot, chilblains) that puts the volunteers at increased risk for an adverse effect
- Cold-induced bronchospasms/asthma
- Blood donation within 8 weeks of the study
- Unwillingness or inability to adhere to study exercise restrictions
- Scheduled MRI within 2 weeks after completing test in cold
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
USARIEM
Natick, Massachusetts, 01760
Michael A Dawson, PhD, 508-206-2278, USARMY.USARIEM-MNDstudies@health.mil
About this study
High daily energy expenditures without compensatory increases in energy intakes results in severe energy deficits during cold-weather military operations. Observational and experimental data from our laboratory suggests that consuming higher-fat, energy dense products can increase energy intake and attenuate energy deficits, however, laboratory analysis is needed to understand the impact of macronutrient manipulation on substrate oxidation and aerobic performance. This proof of concept, randomized crossover study will examine the effects of consuming an isocaloric bar (approximately 350 kcal) that is higher in carbohydrate (CHO: 50% carbohydrate, 30% fat, 20% protein) or higher in fat (FAT: 30% carbohydrate, 50% fat, 20% protein) on substrate oxidation and aerobic performance (time trial) during acute cold (5°C) exposure. Volunteers will wear shorts and a t-shirt during cold exposure, with continuous monitoring of core and skin temperatures. Baseline data will be collected on volunteer height, weight, body composition, and V̇O2peak. To ensure volunteers are familiar with exercise protocols, they will complete practice sessions of all exercise before the start of data collection. Exercise and diet will be controlled throughout data collection. 24 hours prior to data collection, volunteers will consume a lead-in study diet and will abstain from exercise. After 24 hours, volunteers will return to the laboratory for assessment of substrate oxidation and aerobic performance. Volunteers will consume the CHO or FAT treatment bars under cold conditions, followed by 60 minutes of rest prior to the start of exercise. Volunteers will then complete 90 minutes of load carriage steady-state (55 ± 5% VO2peak) treadmill exercise, wearing a ruck with weighing 30% of their total body mass. After steady-state exercise, aerobic performance will be assessed by having volunteers complete a 2-mile time trial. Indirect calorimetry will be used to determine substrate oxidation during steady-state exercise. Serial blood draws will be collected during each trial to assess circulating substrate/hormone responses. Protocol days will be separated by a minimum washout period of 6 days.
Read the detailed description
This randomized crossover double blind control study will examine the effects of consuming an isocaloric bar (approximately 350 kcal) that is higher in carbohydrate (CHO: 50% carbohydrate, 30% fat, 20% protein) or higher in fat (FAT: 30% carbohydrate, 50% fat, 20% protein) on substrate oxidation and aerobic performance (time trial) during acute cold (5°C; Climatic Chamber, Natick, MA) exposure.
The order of the treatment bar assignments will be randomized. Randomization will be created using a random numbers generator (http://randomization.com or similar). Only a designated study staff member will be unblinded to the code for the treatment bars. Volunteers will wear shorts and a t-shirt for all study procedures.
Baseline data will be collected on volunteer height, weight, body composition (dual energy x-ray absorptiometry), and V̇O2peak. To ensure volunteers are familiar with exercise protocols, they will complete practice sessions of all exercise before the start of data collection. Exercise and diet will be controlled throughout data collection. 24 hours prior to data protocol days, volunteers will consume a lead-in study diet and will abstain from exercise. After 24 hours, volunteers will return to the laboratory for assessment of substrate oxidation and aerobic performance. Volunteers will consume the CHO or FAT treatment under cold conditions, followed by a 60 min rest to induced physiological cold responses prior to the start of exercise. Volunteers will then complete 90 min of load carriage (30% body mass) steady-state (55 ± 5% V̇O2peak) treadmill exercise. Indirect calorimetry will be used to determine substrate oxidation during steady-state exercise. Serial blood draws will be collected during each trial to assess circulating substrate/hormone responses. After steady-state exercise, aerobic performance will be assessed by having volunteers complete a 2-mile time trial. There will be a minimum washout period of 6 days.
- Conditions
- Cold Exposure
- Being tested
- High Fat, High Carbohydrate
- Keywords
- endurance exercise, dietary fat, dietary carbohydrate
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
High FatDietary supplement
Higher FatSupplement Bar
High CarbohydrateDietary supplement
Higher Carbohydrate Supplement Bar
| Study group | Role | What they receive |
|---|---|---|
| Higher Fat Supplement Bar | Experimental | Higher Fat, then High Carbohydrate Receives: Dietary Supplement: High Fat |
| Higher Carbohydrate Supplement Bar | Placebo comparator | High Carbohydrate, then High Fat Receives: Dietary Supplement: High Carbohydrate |
What is being measured
The primary outcome is the main question the study is designed to answer.
Endurance Performance
2 mile time trial run
Measured: 30 minutes
Substrate Oxidation
Respiratory Exchange Ratio
Measured: 90 minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Mar 2026
- Study start14 Feb 2026
- Primary completion15 Jul 2026 (estimated)
- Study completion30 Sep 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Cold ExposureStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 8 participants (estimated)
Sponsor and investigators
- Lead sponsor
- United States Army Research Institute of Environmental Medicine
- Sponsor type
- US federal agency
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07489690
- Sponsor's protocol ID
- 25-09H
- Other IDs
- MO240033
- Status last verified
- Feb 2026
- First submitted
- 18 Mar 2026
- Last updated
- 24 Mar 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Margolis LM, Pasiakos SM. Performance nutrition for cold-weather military operations. Int J Circumpolar Health. 2023 Dec;82(1):2192392. doi: 10.1080/22423982.2023.2192392.
PubMed 36934427
Study at a glance
From the registry record, last updated by the sponsor on 24 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Energy Dense Fueling for Cold-Weather Operations
- ClinicalTrials.gov ID
- NCT07489690
- Acronym / sponsor ID
- 25-09H
- Conditions
- Cold Exposure
- Keywords
- endurance exercise, dietary fat, dietary carbohydrate
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 8 participants (estimated)
- Lead sponsor
- United States Army Research Institute of Environmental MedicineUS federal agency
- Study start
- 14 Feb 2026 (actual)
- Primary completion
- 15 Jul 2026 (estimated)
- Study completion
- 30 Sep 2026 (estimated)
- First posted
- 24 Mar 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
High daily energy expenditures without compensatory increases in energy intakes results in severe energy deficits during cold-weather military operations. Observational and experimental data from our laboratory suggests that consuming higher-fat, energy dense products can increase energy intake and attenuate energy deficits, however, laboratory analysis is needed to understand the impact of macronutrient manipulation on substrate oxidation and aerobic performance. This proof of concept, randomized crossover study will examine the effects of consuming an isocaloric bar (approximately 350 kcal) that is higher in carbohydrate (CHO: 50% carbohydrate, 30% fat, 20% protein) or higher in fat (FAT: 30% carbohydrate, 50% fat, 20% protein) on substrate oxidation and aerobic performance (time trial) during acute cold (5°C) exposure. Volunteers will wear shorts and a t-shirt during cold exposure, with continuous monitoring of core and skin temperatures. Baseline data will be collected on volunteer height, weight, body composition, and V̇O2peak. To ensure volunteers are familiar with exercise protocols, they will complete practice sessions of all exercise before the start of data collection. Exercise and diet will be controlled throughout data collection. 24 hours prior to data collection, volunteers will consume a lead-in study diet and will abstain from exercise. After 24 hours, volunteers will return to the laboratory for assessment of substrate oxidation and aerobic performance. Volunteers will consume the CHO or FAT treatment bars under cold conditions, followed by 60 minutes of rest prior to the start of exercise. Volunteers will then complete 90 minutes of load carriage steady-state (55 ± 5% VO2peak) treadmill exercise, wearing a ruck with weighing 30% of their total body mass. After steady-state exercise, aerobic performance will be assessed by having volunteers complete a 2-mile time trial. Indirect calorimetry will be used to determine substrate oxidation during steady-state exercise. Serial blood draws will be collected during each trial to assess circulating substrate/hormone responses. Protocol days will be separated by a minimum washout period of 6 days.
Detailed description
This randomized crossover double blind control study will examine the effects of consuming an isocaloric bar (approximately 350 kcal) that is higher in carbohydrate (CHO: 50% carbohydrate, 30% fat, 20% protein) or higher in fat (FAT: 30% carbohydrate, 50% fat, 20% protein) on substrate oxidation and aerobic performance (time trial) during acute cold (5°C; Climatic Chamber, Natick, MA) exposure.
The order of the treatment bar assignments will be randomized. Randomization will be created using a random numbers generator (http://randomization.com or similar). Only a designated study staff member will be unblinded to the code for the treatment bars. Volunteers will wear shorts and a t-shirt for all study procedures.
Baseline data will be collected on volunteer height, weight, body composition (dual energy x-ray absorptiometry), and V̇O2peak. To ensure volunteers are familiar with exercise protocols, they will complete practice sessions of all exercise before the start of data collection. Exercise and diet will be controlled throughout data collection. 24 hours prior to data protocol days, volunteers will consume a lead-in study diet and will abstain from exercise. After 24 hours, volunteers will return to the laboratory for assessment of substrate oxidation and aerobic performance. Volunteers will consume the CHO or FAT treatment under cold conditions, followed by a 60 min rest to induced physiological cold responses prior to the start of exercise. Volunteers will then complete 90 min of load carriage (30% body mass) steady-state (55 ± 5% V̇O2peak) treadmill exercise. Indirect calorimetry will be used to determine substrate oxidation during steady-state exercise. Serial blood draws will be collected during each trial to assess circulating substrate/hormone responses. After steady-state exercise, aerobic performance will be assessed by having volunteers complete a 2-mile time trial. There will be a minimum washout period of 6 days.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Higher Fat Supplement Bar | Experimental | Dietary Supplement: High FatHigher Fat, then High Carbohydrate |
| Higher Carbohydrate Supplement Bar | Placebo comparator | Dietary Supplement: High CarbohydrateHigh Carbohydrate, then High Fat |
Who may qualify
- Ages
- 18 to 39 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (0 listed)
Key exclusion criteria (15 listed)
- Metabolic or cardiovascular abnormalities, gastrointestinal disorders (i.e., kidney disease, diabetes, cardiovascular disease, hypertension etc.) that is unsuitable for the study determined by OMSO
- Disease or medication (i.e., diabetes medications, statins, corticosteroids, etc) that affects macronutrient utilization and/or the ability to participate in strenuous exercise
- Allergies or intolerance to foods (including but not limited to lactose intolerance/milk allergy), vegetarian practices
- Present condition of alcoholism, anabolic steroids (testosterone, enanthate, undecanoate, etc), or other substance abuse issues
- Unwilling to stop use of nutritional/sports supplements (creatine, multivitamins, whey etc.) while enrolled in the study
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| High FatHigher FatSupplement Bar | Dietary supplement | Higher Fat Supplement Bar |
| High CarbohydrateHigher Carbohydrate Supplement Bar | Dietary supplement | Higher Carbohydrate Supplement Bar |
Primary outcome
Endurance Performance
Time frame: 30 minutes
2 mile time trial run
Substrate Oxidation
Time frame: 90 minutes
Respiratory Exchange Ratio
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Mar 2026.
- Background: PubMed 36934427Margolis LM, Pasiakos SM. Performance nutrition for cold-weather military operations. Int J Circumpolar Health. 2023 Dec;82(1):2192392. doi: 10.1080/22423982.2023.2192392.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing High Fat and High Carbohydrate in people with Cold Exposure, run by United States Army Research Institute of Environmental Medicine at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 0 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 24 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact USARIEM Recruitment (508-206-2278, USARMY.USARIEM-MNDstudies@health.mil), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Endurance Performance (time frame: 30 minutes). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07489690, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Mar 2026; AzTrials last refreshed its copy on 1 Nov 2026.