High-energy nutrition bars for cold-weather exercise
Energy Dense Fueling for Cold-Weather Operations
This will test whether eating a 350-kcal high-fat versus high-carbohydrate bar helps preserve energy stores and aerobic performance during short cold exposure in physically active adults, including military personnel.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 8 (estimated) |
| Ages | 18 Years to 39 Years |
| Sex | All |
| Sponsor | United States Army Research Institute of Environmental Medicine Federal |
| Locations | 1 site (Natick, Massachusetts) |
| Trial ID | NCT07489690 on ClinicalTrials.gov |
What this trial studies
In a randomized, double-blind crossover design, physically active adults will consume isocaloric 350 kcal bars that differ by macronutrient composition (higher-carbohydrate: 50% CHO/30% fat/20% protein vs higher-fat: 30% CHO/50% fat/20% protein) before exercise in a 5°C climatic chamber. Baseline measures include height, weight, DXA body composition, and V̇O2peak, and participants complete practice sessions to standardize exercise familiarity. Diet and activity are controlled with a 24-hour lead-in diet, participants consume the assigned bar under cold conditions, rest for 60 minutes to induce physiological cold responses, then perform an aerobic time-trial while substrate oxidation and temperatures are monitored. The order of bar assignments is randomized and only a designated staff member is unblinded to treatment codes.
Who should consider this trial
Good fit: Ideal candidates are healthy, physically active adults aged 18–39 (17 if active military) with BMI 18.5–30 kg/m2 who can abstain from alcohol, nicotine, and nonstudy supplements during controlled diets and who have supervisor approval if required.
Not a fit: People with metabolic, cardiovascular, or gastrointestinal disorders, those outside the age or BMI range, or those unable to follow the controlled diet and activity restrictions are unlikely to benefit from participation.
Why it matters
Potential benefit: If successful, this approach could help military personnel and other active people maintain energy balance and aerobic performance during cold-weather operations.
How similar studies have performed: Previous observational and experimental work suggests higher-fat, energy-dense products can increase intake and reduce energy deficits in field settings, but tightly controlled laboratory crossover testing of substrate oxidation and performance in cold conditions is more novel.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: • Men and women aged 18 - 39 years (17 if active Military) * Physically active (exercise minimum 2 days per week) * Have supervisor approval (permanent party military and civilians at NSSC) * Willing to refrain from alcohol, nicotine products and dietary supplement use while on study diets * Females must have normal menstrual cycles between 26-32 days in duration; 5 menstrual cycles within the past 6 months; or using oral/hormonal contraceptive which contains low-dose estrogen/progesterone to maintain continuous levels throughout the 28-day cycle (i.e., no placebos) * Only consume caffeine products while on study diets if provided by study staff * Body mass index (BMI) between 18.5-30 kg/m2 * In good health as determined by OMSO (Office of Medical Support and Oversight) Exclusion Criteria: * 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 * 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
Where this trial is running
Natick, Massachusetts
- Usariem — Natick, Massachusetts, United States (Recruiting)
Study contacts
- Study coordinator: USARIEM Recruitment
- Email: USARMY.USARIEM-MNDstudies@health.mil
- Phone: 508-206-2278
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.