Performance nutrition for cold-weather military operations.
Lee M Margolis, Stefan M Pasiakos
https://pubmed.ncbi.nlm.nih.gov/36934427Actively Recruiting
Phase Not Applicable
Age: 18Years - 39Years
All Genders
Healthy Volunteers
ID07489690
Energy Dense Fueling for Cold-Weather Operations: A Randomized Double-Blind Crossover Study Comparing High Fat and High Carbohydrate Supplement Bars on Substrate Oxidation and Aerobic Performance
Led by United States Army Research Institute of Environmental Medicine · Updated on 2026-03-24
8
Participants Needed
1
Research Sites
11 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
Researchers are studying how different types of energy bars affect the body's use of fuel and aerobic performance during cold weather exposure. This randomized crossover study focuses on healthy adults aged 18 to 39 years who perform exercise in a cold environment (5°C) while wearing light clothing. The goal is to understand how bars higher in carbohydrate or higher in fat impact energy use and endurance during cold-weather military operations. Participants consume one of two types of isocaloric supplement bars (approximately 350 kcal): one higher in carbohydrates (50% carbs, 30% fat, 20% protein) or one higher in fat (30% carbs, 50% fat, 20% protein). The order of consumption is randomized and double-blinded. After consuming the bar, volunteers rest for 60 minutes in cold conditions, then perform 90 minutes of treadmill exercise carrying a load equal to 30% of their body weight. This is followed by a 2-mile time trial to assess endurance performance. There is a minimum washout period of six days between trials. During the study, researchers collect baseline data (height, weight, body composition, peak oxygen uptake) and monitor core and skin temperatures continuously. Indirect calorimetry is used to measure substrate oxidation during exercise, and serial blood samples assess circulating substrates and hormones. Exercise and diet are controlled, including a lead-in diet 24 hours before each trial. The study measures endurance performance over 30 minutes and substrate oxidation over 90 minutes. Participants are asked to abstain from alcohol, nicotine, and other supplements during the study periods.
CONDITIONS
Brief Title
Energy Dense Fueling for Cold-Weather Operations
Who Can Participate
Age: 18Years - 39Years
All Genders
Healthy Volunteers
Eligibility Criteria
You may qualify if you...
- Men and women aged 18 to 39 years (17 if active military)
- Physically active, exercising at least 2 days per week
- Have supervisor approval if permanent party military or civilian at NSSC
- Willing to refrain from alcohol, nicotine, and dietary supplements during study diets
- Females must have normal menstrual cycles between 26-32 days for 5 cycles in past 6 months, or use specific hormonal contraceptives
- Only consume caffeine if provided by study staff
- Body mass index between 18.5 and 30 kg/m2
- In good health as determined by Office of Medical Support and Oversight (OMSO)
You will not qualify if you...
- Metabolic or cardiovascular abnormalities or gastrointestinal disorders unsuitable for study as determined by OMSO
- Diseases or medications affecting macronutrient use or ability to exercise strenuously
- Food allergies or intolerances, including lactose intolerance or vegetarian practices
- Current alcoholism, anabolic steroid use, or other substance abuse issues
- Unwilling to stop nutritional or sports supplements during study
- Sensitivity to medical adhesives causing significant skin irritation
- Acute or chronic musculoskeletal injuries affecting running or ruck marching
- History of gastrointestinal diseases or surgery
- Difficulty swallowing large pills or unwilling to use rectal temperature sensor
- Raynaud's syndrome
- History of cold injuries such as frostbite or trench foot
- Cold-induced bronchospasms or asthma
- Blood donation within 8 weeks of study
- Unwillingness or inability to follow exercise restrictions
- Scheduled MRI within 2 weeks after cold test
AI-Screening
AI-Powered Screening
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2
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Your Study Journey
Screening
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 screening and enrollment visit
Treatment
Duration - Two treatment periods with a minimum 6-day washout period between them
Participants consume either a high carbohydrate or high fat supplement bar under cold conditions before performing exercise tests. This includes a rest period to induce cold responses, followed by 90 minutes of treadmill exercise with load carriage, and then a 2-mile aerobic performance time trial. Participants undergo two treatment periods with a minimum 6-day washout in between, receiving both supplement types in random order.
2 main treatment visits (in-person) with at least 6 days between visits
Trial Site Locations
Total: 1 location
1
USARIEM
Natick, Massachusetts, United States, 01760
Actively Recruiting
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Research Team
U
USARIEM Recruitment
How is the study designed?
Study Type
INTERVENTIONAL
Masking
DOUBLE
Allocation
RANDOMIZED
Model
CROSSOVER
Primary Purpose
TREATMENT
Number of Arms
2
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