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Background Dietary supplement (DS) use by Army personnel is high and is a safety and readiness issue. Objective Our aim was to examine factors motivating use of DSs among US Army personnel and preferred safety education strategies. Design This mixed-method study used a validated DS questionnaire and subsequent focus groups that were formed based on questionnaire-identified demographic characteristics. An embedded qualitative dominant design was used. Participants/setting Data were collected from April to July 2015 from active duty soldiers at 3 military installations in the United States. Main outcome measures A self-report questionnaire (n = 289) provided data on demographic characteristics, health, exercise, detailed use, and attitudes regarding DS safety and efficacy. Fourteen focus-group sessions (n = 129) examined factors motivating DS use, education strategies, and identified themes and DS-related behaviors. Statistical analysis performed Descriptive statistics and χ2 analyses were conducted. Results Of the soldiers who completed questionnaires, 83% were male, 60% were enlisted, and 40% were officers; mean age ± standard deviation was 27.6 ± 0.36 years and 75% used at least 1 type of DS per week: 52% used protein/amino acids, 47% used multivitamins/minerals, and 35% used a combination of products. Focus groups indicated reasons for use included physical appearance, fitness, peer endorsement, ease of access, limited availability of healthy food, occupational demands, and health. Participants requested education from an expert on safe use that was not focused on dangerous products. Conclusions Soldiers are high DS users, especially products marked for purported performance enhancement. Motivating factors for DS use are fitness/appearance and occupational demands, but soldiers lack knowledge of DS regulatory requirements and safety/efficacy. Soldiers wished to receive education on DSs from trusted health care professionals, such as registered dietitian nutritionists, that was not focused on dangerous products. Study findings suggest guidance and education should occur before periods of high DS use, such as deployment.

The US military Meal, Ready-to-Eat food ration is approved as a nutritionally adequate sole source of nutrition for ≤21 days. However, the ration continuously evolves, requiring periodic reassessment of its influence on nutritional status and health.To determine the effects of consuming the US Armed Services Meal, Ready-to-Eat ration for 21 days, relative to usual diets, on nutrient intake, and indicators of nutritional status and cardiometabolic health.Parallel-arm, randomized, controlled trial, secondary analysis.Sixty healthy, weight stable, free-living adults from the Natick, MA, area participated between June 2015 and March 2017.Participants were randomized to consume their usual diet for 31days (CON), or a strictly controlled Meal, Ready-to-Eat-only diet for 21 days followed by their usual diet for 10 days (MRE).Nutrient intake (absolute and adjusted) throughout the study period, and indicators of nutrition status (vitamins B, D, folate, homocysteine, iron, magnesium, and zinc) and cardiometabolic health (glucose, insulin, and blood lipid levels) before (Day 0), during (Day 10 through Day 21), and after (Day 31) the intervention period.Between-group differences over time were assessed using marginal models. Models for nutritional status and cardiometabolic health indicators were adjusted for age, initial body mass index, and baseline value of the dependent variable.Energy-adjusted fiber; polyunsaturated fatty acids; vitamins A, thiamin, riboflavin, B-6, C, D, and E; and magnesium and zinc intakes all increased in MRE during the intervention and were higher compared with CON (P0.05), whereas relative protein intake decreased and was lower (P0.05). Serum triglyceride concentrations averaged 19% (95% CI 0% to 41%) higher in MRE relative to CON during Days 10 to 31 (P=0.05). No statistically significant effects of diet on any other nutritional status or cardiometabolic health indicators were observed.Findings demonstrate that a Meal, Ready-to-Eat ration diet can provide a more micronutrient-dense diet than usual dietary intake aiding in maintenance of nutritional status over 21 days.

Enhancing dietary omega-3 highly unsaturated fatty acids (n-3 HUFA) intake may confer neuroprotection, brain resiliency, improve wound healing and promote cardiovascular health. This study determined the efficacy of substituting a few common foods (chicken meat, chicken sausage, eggs, salad dressings, pasta sauces, cooking oil, mayonnaise, and peanut butter) lower in omega-6 polyunsaturated fatty acids (n-6 PUFA) and higher in n-3 HUFA in a dining facility on blood fatty acid profile. An eight-week prospective, between-subjects (n = 77), repeated measures, parallel-arm trial was conducted. Participants self-selected foods consumed from conventionally produced foods (control), or those lower n-6 PUFA and higher n-3 HUFA versions (intervention). Changes in blood omega-3 index, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), n-6 PUFA, lipid profile, and food satisfaction were main outcomes. Between-group differences over time were assessed using a linear mixed model to measure the effect of diet on blood serum fatty acids and inflammatory markers. The intervention group achieved a higher omega-3 index score (3.66 ± 0.71 vs. 2.95 ± 0.77; p < 0.05), lower total n-6 (10.1 ± 4.6 vs. 15.3 ± 6.7 µg/mL; p < 0.05), and higher serum concentration of EPA (5.0 ± 1.31 vs. 4.05 ± 1.56 µg/mL; p < 0.05) vs. controls. Satisfaction in intervention foods improved or remained consistent. Substitution of commonly eaten dining facility foods with like-items higher in DHA and EPA and lower in n-6 PUFA can favorably impact fatty acid status and the omega-3 index.

Background Initiating aerobic exercise with low muscle glycogen content promotes greater fat and less endogenous carbohydrate oxidation during exercise. However, the extent exogenous carbohydrate oxidation increases when exercise is initiated with low muscle glycogen is unclear. Purpose Determine the effects of muscle glycogen content at the onset of exercise on whole-body and muscle substrate metabolism. Methods Using a randomized, crossover design, 12 men (mean ± SD, age: 21 ± 4 y; body mass: 83 ± 11 kg; VO2peak: 44 ± 3 mL/kg/min) completed 2 cycle ergometry glycogen depletion trials separated by 7-d, followed by a 24-h refeeding to elicit low (LOW; 1.5 g/kg carbohydrate, 3.0 g/kg fat) or adequate (AD; 6.0 g/kg carbohydrate, 1.0 g/kg fat) glycogen stores. Participants then performed 80 min of steady-state cycle ergometry (64 ± 3% VO2peak) while consuming a carbohydrate drink (95 g glucose +51 g fructose; 1.8 g/min). Substrate oxidation (g/min) was determined by indirect calorimetry and 13C. Muscle glycogen (mmol/kg dry weight), pyruvate dehydrogenase (PDH) activity, and gene expression were assessed in muscle. Results Initiating steady-state exercise with LOW (217 ± 103) or AD (396 ± 70; P 0.05) during exercise. Endogenous carbohydrate oxidation was lower and fat oxidation was higher in LOW (0.75 ± 0.29 and 0.55 ± 0.10) than AD (1.17 ± 0.29 and 0.38 ± 0.13; all P Conclusion Initiating exercise with low muscle glycogen does not impair exogenous carbohydrate oxidative capacity, rather, to compensate for lower endogenous carbohydrate oxidation acute adaptations lead to increased whole-body and skeletal muscle fat oxidation.

Consumption of certain berries appears to slow postprandial glucose absorption, attributable to polyphenols, which may benefit exercise and cognition, reduce appetite and/or oxidative stress. This randomised, crossover, placebo-controlled study determined whether polyphenol-rich fruits added to carbohydrate-based foods produce a dose-dependent moderation of postprandial glycaemic, glucoregulatory hormone, appetite andex vivooxidative stress responses. Twenty participants (eighteen males/two females; 24 (sd5) years; BMI: 27 (sd3) kg/m2) consumed one of five cereal bars (approximately 88 % carbohydrate) containing no fruit ingredients (reference), freeze-dried black raspberries (10 or 20 % total weight; LOW-Rasp and HIGH-Rasp, respectively) and cranberry extract (0·5 or 1 % total weight; LOW-Cran and HIGH-Cran), on trials separated by ≥5 d. Postprandial peak/nadir from baseline (Δmax) and incremental postprandial AUC over 60 and 180 min for glucose and other biochemistries were measured to examine the dose-dependent effects. Glucose AUC0–180 mintrended towards being higher (43 %) after HIGH-Raspv.LOW-Rasp (P=0·06), with no glucose differences between the raspberry and reference bars. Relative to reference, HIGH-Rasp resulted in a 17 % lower Δmaxinsulin, 3 % lower C-peptide (AUC0–60 minand 3 % lower glucose-dependent insulinotropic polypeptide (AUC0–180 min)Pex vivooxidation, appetite-mediating hormones or appetite. Fortification with freeze-dried black raspberries (approximately 25 g, containing 1·2 g of polyphenols) seems to slightly improve the glucoregulatory hormone and glycaemic responses to a high-carbohydrate food item in young adults but did not affect appetite or oxidative stress responses at doses or with methods studied herein.

Introduction Effective, standardized, and easily accessible weight management programs are urgently needed for military beneficiaries. Videoconference interventions have the potential for widespread scaling, and can provide both real time interaction and flexibility in delivery times regardless of location, but there is little information on their effectiveness and acceptability. Materials and Methods This study as part of a larger weight loss trial describes the videoconference adaption of Group Lifestyle Balance (GLB) program, a community group-based Diabetes Prevention Program intervention, and provides a comparison of weight loss and meeting attendance between in-person and videoconference delivery modes over 12 weeks in adult family members of military service members. Forty-three participants were enrolled from two military installations and received either the videoconference-adapted or an in-person GLB program in a non-randomized trial design. Differences in program attendance and percent weight lost at 12 weeks were compared by independent samples t-tests and nonparametric methods. Group differences in the percentage of weight lost over the 12-week period were analyzed using a linear mixed model. Results All GLB intervention components were successfully delivered by videoconference with minor adaptations for the different delivery mechanism. Participant retention was 70% and 96% in the in-person and videoconference groups, respectively (p = 0.04). Completing participants in both groups lost a significant percent body weight over the 12 week intervention (p < 0.001) and there was no difference in percent body weight after 12 weeks of intervention (6.2 ± 3.2% and 5.3 ± 3.4% for in-person and videoconference at 12 weeks, respectively; p = 0.60). Conclusion This study describes the first videoconference adaption of the GLB program for use in military families. Attrition was lower in the videoconference group, and there were a similar levels of weight loss in both groups regardless of delivery modality. Videoconference weight loss interventions are effective and feasible for scaling to support healthy weight management in military as well as civilian populations.

BACKGROUND Lifestyle interventions are the first-line treatment for obesity, but participant weight loss is typically low. OBJECTIVES We evaluated the efficacy of an alternative lifestyle intervention [Healthy Weight for Living (HWL)] compared with a modified Diabetes Prevention Program (m-DPP). HWL was based on a revised health behavior change model emphasizing hunger management and the development of healthy food preferences. m-DPP was a standard Diabetes Prevention Program implemented with counselor time matched to HWL. Participants were adult dependents of military personnel and had overweight or obesity. METHODS Participants were randomly assigned to HWL (n = 121) or m-DPP (n = 117), delivered primarily by group videoconference with additional midweek emails. The primary outcome was 12-mo weight change. Secondary outcomes included 6-mo changes in cardiometabolic risk factors and diet. Intention-to-treat (ITT) and complete case (CC) analyses were performed using linear mixed models. RESULTS Retention did not differ between groups (72% and 66% for HWL and m-DPP at 12 mo, respectively; P = 0.30). Mean ± SE adjusted 12-mo weight loss in the ITT cohort was 7.46 ± 0.85 kg for HWL and 7.32 ± 0.87 kg for m-DPP (P = 0.91); in the CC cohort, it was 7.83 ± 0.82 kg for HWL and 6.86 ± 0.88 kg for m-DPP (P = 0.43). Thirty-eight percent of HWL and 30% of m-DPP completers achieved ≥10% weight loss (P = 0.32). Improvements in systolic blood pressure, LDL cholesterol, triglycerides, fasting glucose, general health, sleep, and mood were similar across groups; improvements in diastolic blood pressure were greater in m-DPP. Adjusted group mean reductions in energy intake were not significantly different between groups, but HWL participants were more adherent to their dietary prescription for lower glycemic index and high fiber and protein (P = 0.05 to

Objective: Humans avoid overheating through physiological and behavioral mechanisms. However, elite athletes, industrial workers, and military personnel, driven by the tasks at hand, may choose to continue working and face an increased risk of exertional heat illness (EHI). We wanted to examine the efficacy of a new core temperature (Tcr) estimation algorithm in assessing EHI risk. Approach: Physiological responses of 21 male Royal Marines recruits (age 21±2 y, height 1.79±0.05 m, weight 80.5±7.2 kg) were collected during a physically-demanding criterion road march (14.5 km in 90 min with a 9.6 kg load; air temperature 16°C, relative humidity ≥ 84%). Measured Tcr (thermometer pill) and estimated Tcr (ECTempTM Tcr-est) were compared. Main Results: Measured Tcr either increased to an asymptote Tcr 40.0°C (HOT; n=10). In the HOT group, Tcr-est reflected measured Tcr up to Tcr = 40.0°C (Bias = −0.10 ± 0.37°C, root mean square error = 0.37 ± 0.13°C). In the WARM group, Tcr-est overestimated Tcr (Bias = 0.34 ± 0.40°C) and was higher from mid-point to end. A logistic regression (Skin temperature approximate entropy and mean heart rate) was able to predict group membership (95% accuracy) at 20 minutes, allowing a WARM group ECTemp(TM) correction factor (corrected Bias=0.00 ± 0.29°C). Significance: The Tcr-est successfully tracked Tcr in the HOT group with high risk of exertional heat illness (EHI) (40% incidence). Skin temperature complexity shows promise as a non-invasive means of insight into the state of thermoregulatory control mechanisms.

Objective To assess the impact of the Special Operations Forces Human Performance Program dining facility (DFAC) intervention on patron diet quality and meal satisfaction. Design Nonrandomized, controlled time series study using digital food photography and surveys pre-post intervention (0, 4, 8, and 12 months). Setting Two Fort Bragg, NC military installation DFACs. Participants Volunteers (n = 688 total; n = 573 complete dataset) were US Army active duty soldiers. Intervention The DFAC intervention included food choice architecture, new performance-optimizing food recipes to increase nutrient density, revised menus to offer more performance foods daily, and nutrition labeling to influence food choice. Main Outcome Measures Daily DFAC nutrient intake and Healthy Eating Index (HEI) 2010 scores. Analysis Descriptive and ANOVA statistical analyses were performed between control and intervention groups and from baseline to 4, 8, and 12 months postintervention (α = .05; 80% power). Results The intervention resulted in a higher posttest HEI score (60.1 ± 8.8 points; +3.4%; P = .005) and DFAC satisfaction compared with control (49.0 ± 10.4 points; P > .05). Improved intervention HEI scores were attributed to changes in citrus and melon fruit (+46%), red and orange vegetables (+35%), whole grains (+181%), legumes (65%), yogurt (+45%), oils (–26%), and solid fat (–18%) consumption (all P Conclusions and Implications These data illustrate that the Special Operations Forces Human Performance Program military DFAC nutrition intervention was feasible to implement and was associated with diet quality improvements. Access to high-quality ingredients and recipes may improve soldier meal quality and acceptance in other settings and warrants further investigation.

Background Fluid intake during military training is prescribed based on the interactions among work rates, environmental conditions, and uniform configurations. The efficacy of this guidance has not been empirically assessed in over a decade. To determine the acceptability of the fluid intake guidance, sweat losses were measured in a variety of conditions with modern uniform/body armor configurations and were then compared to prescribed fluid intakes for each condition (workload, environment, clothing). Methods Whole body sweat losses of 324 Soldiers and 14 model simulations were measured under a variety of work intensities ((Watts) easy, moderate, hard), work durations (2-25 h), environmental conditions (White-Black flag), and uniform configurations (including Army Combat Uniform and body armor). Whole body sweat losses were then calculated relative to 4 h drinking guidance and in accordance with TB MED 507 recommended work/rest ratios. The differences between the prescribed fluid intake and sweat loss were calculated and expressed as a percent loss or gain of body weight. Values within a threshold of ±2% body water flux (BWF) were deemed an acceptable conservative starting point for performance and health concerns. Findings Values within ±2% BWF numbered 309/338; 25 of 338 observations exceeded the +2% BWF while 4 of 338 observations exceeded the -2% BWF. When total fluid restriction was simulated, all experienced body weight loss with 151 of 338 observations exceeding the -2% BWF. Discussion When calculated using actual measured sweating rates from the laboratory and model simulations, current fluid intake guidance appears to predict with 91.4% accuracy the volume of fluid required to maintain a proper euhydrated state (±2%) during 4 h of exercise. Simulations of total fluid restriction support the necessity for fluid intake guidance so that the Warfighter's performance does not degrade. It is recommended that the current military fluid intake guidance focuses on methods for accurately tracking fluid intakes.

Systemic immune function is impaired by sleep restriction. However, the impact of sleep restriction on local immune responses and to what extent any impairment can be mitigated by nutritional supplementation is unknown. We assessed the effect of 72-h sleep restriction (2-h nightly sleep) on local immune function and skin barrier restoration of an experimental wound, and determined the influence of habitual protein intake (1.5 g·kg−1·day−1) supplemented with arginine, glutamine, zinc sulfate, vitamin C, vitamin D3, and omega-3 fatty acids compared with lower protein intake (0.8 g·kg−1·day−1) without supplemental nutrients on these outcomes. Wounds were created in healthy adults by removing the top layer of less than or equal to eight forearm blisters induced via suction, after adequate sleep (AS) or 48 h of a 72-h sleep restriction period (SR; 2-h nightly sleep). A subset of participants undergoing sleep restriction received supplemental nutrients during and after sleep restriction (SR+). Wound fluid was serially sampled 48 h postblistering to assess local cytokine responses. The IL-8 response of wound fluid was higher for AS compared with SR [area-under-the-curve (log10), 5.1 ± 0.2 and 4.9 ± 0.2 pg/ml, respectively; P = 0.03]; and both IL-6 and IL-8 concentrations were higher for SR+ compared with SR ( P < 0.0001), suggestive of a potentially enhanced early wound healing response. Skin barrier recovery was shorter for AS (4.2 ± 0.9 days) compared with SR (5.0 ± 0.9 days) ( P = 0.02) but did not differ between SR and SR+ ( P = 0.18). Relatively modest sleep disruption delays wound healing. Supplemental nutrition may mitigate some decrements in local immune responses, without detectable effects on wound healing rate. NEW & NOTEWORTHY The data herein characterizes immune function in response to sleep restriction in healthy volunteers with and without nutrition supplementation. We used a unique skin wound model to show that sleep restriction delays skin barrier recovery, and nutrition supplementation attenuates decrements in local immune responses produced by sleep restriction. These findings support the beneficial effects of adequate sleep on immune function. Additional studies are necessary to characterize practical implications for populations where sleep restriction is unavoidable.

Background Accurate assessment of dietary intake continues to challenge researchers, especially in field, or non-laboratory settings. Objective In this study, digital food photography (DFP) methodology was used to assess nutritional intake (NI) of Soldiers participating in the US Army's Ranger Selection and Assessment Program (RASP). Methods During this high-intensity six-week course, Soldiers complete simulated operational missions, perform various military tasks, and importantly, eating time is severely limited. Therefore, this study provided an opportunity to evaluate the utility of DFP methods for accurate assessment of energy balance in conditions where consumption of large numbers of subjects must be completed in a very short periods of time (≤20 min). NI of 131 male, enlisted Soldiers (21 ± 4 years, 178±7 cm, and 78±8 kg) enrolled in the RASP course was assessed in their garrison dining facility using DFP utilizing visual estimation of pre- and post-meal photos of participant meals concurrently with photos of weighed, standardized portions. Total daily energy expenditure (TDEE) was assessed using doubly-labeled water (2H218O) in a sub-group of 19 volunteers. Results During the study, data loss (i.e., missing meal photos) was less than 5% per meal, and during the visual estimation process discrepancies in food identification averaged less than 10% per meal, while approximately a third of serving size estimations required a third party adjudication prior to finalization and calculation NI. Conclusions We conclude that the use of DFP allows an adequately reliable approach for quantifying NI in real-world scenarios involving large numbers of participants who must be assessed very rapidly, and researchers must have a small footprint.

New Findings What is the topic of this review? There is a need to revisit the basic principles of exercise mass and water balance, the use of common equations and the practice of interpreting outcomes. What advances does it highlight? We propose use of the following equation as a way of simplifying exercise mass and water balance calculations in conditions where food is not consumed and waste is not excreted: ∆body mass − 0.20 g/kcal−1 = ∆body water. The relative efficacy of exercise drinking behaviours can be judged using the following equation: percentage dehydration = [(∆body mass − 0.20 g kcal−1)/starting body mass] × 100. Changes in body mass occur because of flux in liquids, solids and gases. This knowledge is crucial for understanding metabolism, health and human water needs. In exercise science, corrections to observed changes in body mass to estimate water balance are inconsistently applied and often misinterpreted, particularly after prolonged exercise. Although acute body mass losses in response to exercise can represent a close surrogate for body water losses, the discordance between mass and water balance equivalence becomes increasingly inaccurate as more and more energy is expended. The purpose of this paper is briefly to clarify the roles that respiratory water loss, gas exchange and metabolic water production play in the correction of body mass changes for fluid balance determinations during prolonged exercise. Computations do not include waters of association with glycogen because any movement of water among body water compartments contributes nothing to water or mass flux from the body. Estimates of sweat loss from changes in body mass should adjust for non-sweat losses when possible. We propose use of the following equation as a way of simplifying the study of exercise mass and water balance: ∆body mass − 0.20 g kcal−1 = ∆body water. This equation directly controls for the influence of energy expenditure on body mass balance and the approximate offsetting equivalence of respiratory water loss and metabolic water production on body water balance. The relative efficacy of exercise drinking behaviours can be judged using the following equation: percentage dehydration = [(∆body mass − 0.20 g kcal−1)/starting body mass] × 100.

Military personnel generally under-consumen-3 fatty acids and overconsumen-6 fatty acids. In a placebo-controlled, double-blinded study, we investigated whether a diet suitable for implementation in military dining facilities and civilian cafeterias could benefitn-3/n-6 fatty acid status of consumers. Three volunteer groups were provided different diets for 10 weeks. Control (CON) participants consumed meals from the US Military’s Standard Garrison Dining Facility Menu. Experimental, moderate (EXP-Mod) and experimental-high (EXP-High) participants consumed the same meals, but highn-6 fatty acid and lown-3 fatty acid containing chicken, egg, oils and food ingredients were replaced with products having lessn-6 fatty acids and moren-3 fatty acids. The EXP-High participants also consumed smoothies containing 1000 mgn-3 fatty acids per serving, whereas other participants received placebo smoothies. Plasma and erythrocyte EPA and DHA in CON group remained unchanged throughout, whereas EPA, DHA and Omega-3 Index increased in EXP-Mod and EXP-High groups, and were higher than in CON group after 5 weeks. After 10 weeks, Omega-3 Index in EXP-High group had increased further. No participants exhibited changes in fasting plasma TAG, total cholesterol, LDL, HDL, mood or emotional reactivity. Replacing high linoleic acid (LA) containing foods in dining facility menus with similar high oleic acid/low LA and highn-3 fatty acid foods can improven-6/n-3 blood fatty acid status after 5 weeks. The diets were well accepted and suitable for implementation in group feeding settings like military dining facilities and civilian cafeterias.

Interactions between gut microbes and dietary components modulate intestinal permeability (IP) and inflammation. Recent studies have reported altered fecal microbiota composition together with increased IP and inflammation in individuals consuming military food rations in austere environments, but could not isolate effects of the diet from environmental factors. To determine how the U.S. Meal, Ready-to-Eat food ration affects fecal microbiota composition, IP and inflammation, 60 adults (95% male,18-61 years) were randomized to consume their usual ad libitum diet for 31 days (CON) or a strictly controlled Meal, Ready-to-Eat-only diet for 21 days followed by their usual diet for 10 days (MRE). In both groups, fecal microbiota composition was measured before, during (INT, days 1-21) and after the intervention period. IP and inflammation [high-sensitivity C-reactive protein (hsCRP)] were measured on days 0, 10, 21 and 31. Longitudinal changes in fecal microbiota composition differed between groups (P=.005), and fecal samples collected from MRE during INT were identified with 88% accuracy using random forest models. The genera making the strongest contribution to that prediction accuracy included multiple lactic acid bacteria (Lactobacillus, Lactococcus, Leuconostoc), which demonstrated lower relative abundance in MRE, and several genera known to dominate the ileal microbiota (Streptococcus, Veillonella, Clostridium), the latter two demonstrating higher relative abundance in MRE. IP and hsCRP were both lower (34% and 41%, respectively) in MRE relative to CON on day 21 (P

When sea‐level (SL) residents rapidly ascend to high altitude (HA), plasma volume (PV) decreases. A quantitative model for predicting individual %∆PV over the first 7 days at HA has recently been developed from the measurements of %∆PV in 393 HA sojourners. We compared the measured %∆PV with the %∆PV predicted by the model in 17 SL natives living 21 days at HA (4300 m). Fasting hematocrit (Hct), hemoglobin (Hb) and total circulating protein (TCP) concentrations at SL and on days 2, 7, 13, and 19 at HA were used to calculate %∆TCP and %∆PV. Mean [95%CI] measured %∆PV on HA2, 7, 13 and 19 was −2.5 [−8.2, 3.1], −11.0 [−16.6, −5.5], −11.7 [−15.9, −7.4], and −16.8 [−22.2, −11.3], respectively. %∆PV and %∆TCP were positively correlated (P

The objective of the study was to evaluate how controlled, short-term sleep restriction (SR; 72 h) alters markers of bone formation and resorption and urinary calcium (Ca) output. Ten healthy, sleep-adequate, male soldiers were housed in the research facility one day prior to and for the duration of SR. Diet was controlled to provide adequate energy balance and macronutrient distribution, meeting the recommended dietary allowance (RDA) for Ca. Subjects engaged in light activities to maintain wakefulness and were allowed 2 h of sleep per night (0430–0630 hours). Blood samples were collected each morning at 0 h (baseline) and 24, 48, and 72 h of SR. Serum was assayed for parathyroid hormone (PTH), bone alkaline phosphatase (BAP), tartrate-resistant acid phosphatase (TRAP), and C-terminal telopeptide of type I collagen (CTX). Urine was collected in 24 h increments during SR for measurement of Ca and creatinine (Cr). BAP was reduced at 24 h (P= 0.015) and resorption markers TRAP and CTX were increased after 48 and 72 h of SR compared to baseline (P

Soldiers often experience negative energy balance during military operations that diminish whole-body protein retention, even when dietary protein is consumed within recommended levels (1.5-2.0 g·kg·d).The objective of this study is to determine whether providing supplemental nutrition spares whole-body protein by attenuating the level of negative energy balance induced by military training and to assess whether protein balance is differentially influenced by the macronutrient source.Soldiers participating in 4-d arctic military training (AMT) (51-km ski march) were randomized to receive three combat rations (CON) (n = 18), three combat rations plus four 250-kcal protein-based bars (PRO, 20 g protein) (n = 28), or three combat rations plus four 250-kcal carbohydrate-based bars daily (CHO, 48 g carbohydrate) (n = 27). Energy expenditure (D2O) and energy intake were measured daily. Nitrogen balance (NBAL) and protein turnover were determined at baseline (BL) and day 3 of AMT using 24-h urine and [N]-glycine.Protein and carbohydrate intakes were highest (P0.05) for PRO (mean ± SD, 2.0 ± 0.3 g·kg·d) and CHO (5.8 ± 1.3 g·kg·d), but only CHO increased (P0.05) energy intake above CON. Energy expenditure (6155 ± 515 kcal·d), energy balance (-3313 ± 776 kcal·d), net protein balance (NET) (-0.24 ± 0.60 g·d), and NBAL (-68.5 ± 94.6 mg·kg·d) during AMT were similar between groups. In the combined cohort, energy intake was associated (P0.05) with NET (r = 0.56) and NBAL (r = 0.69), and soldiers with the highest energy intake (3723 ± 359 kcal·d, 2.11 ± 0.45 g protein·kg·d, 6.654 ± 1.16 g carbohydrate·kg·d) achieved net protein balance and NBAL during AMT.These data reinforce the importance of consuming sufficient energy during periods of high energy expenditure to mitigate the consequences of negative energy balance and attenuate whole-body protein loss.

BACKGROUND Adaptive responses of appetite-mediating hormones to negative energy balance are thought to contribute to a counterregulatory response that drives weight regain, but they have not been studied while controlling for reduced diet volume. OBJECTIVE In this secondary analysis, we aimed to determine the effects of short-term, severe energy deprivation (ED) on appetite and appetite-mediating hormone concentrations. METHODS Twenty-one adults with a mean ± SD age of 21 ± 3 y and body mass index of 25 ± 3 kg/m(2) consumed isovolumetric diets provided over separate 48-h periods while increasing habitual energy expenditure by 1683 ± 329 kcal/d through light- and moderate-intensity exercise. Energy intake was matched to energy expenditure to maintain energy balance (EB) (-44 ± 92 kcal/d) or was

Background A stress fracture (SF) is a highly debilitating injury commonly experienced in United States Army Basic Combat Training (BCT). Body fat (BF) may be associated with this injury but previous investigations (in athletes) have largely used SF self-reports and lacked sufficient statistical power. This investigation developed an equation to estimate %BF and used that equation to examine the relationship between %BF and SF risk in BCT recruits. Methods Data for the %BF predictive equation involved 349 recruits with BF obtained from dual-energy X-ray absorptiometry. %BF was estimated using body mass index (BMI, weight/height2), age (yr), and sex in the entire population of BCT recruits over an 11-year period (n = 583,651). Medical information was obtained on these recruits to determine SF occurrence. Recruits were separated into deciles of estimated %BF and the risk of SFs determined in each decile. Results The equation was %BF = − 7.53 + 1.43 ● BMI + 0.13 ● age − 14.73 ● sex, with sex either 1 for men or 0 for women (r = 0.88, standard error of estimate = 4.2%BF). Among the men, SF risk increased at the higher and lower %BF deciles: compared to men in the mean %BF decile, the risk of a SF for men in the first (lowest %BF) and tenth (highest %BF) decile were 1.27 (95%confidence interval (95%CI) = 1.17–1.40) and 1.15 (95%CI = 1.05–1.26) times higher, respectively. Among women, SF risk was only elevated in the first %BF decile with risk 1.20 (95%CI = 1.09–1.32) times higher compared to the mean %BF decile. Conclusions Low %BF was associated with higher SF risk in BCT; higher %BF was associated with higher SF risk among men but not women.

Skin wound healing models can be used to detect changes in immune function in response to interventions. This study used a test-retest format to assess the reliability of a skin suction blister procedure for quantitatively evaluating human immune function in repeated measures type studies. Up to eight suction blisters (~30 mm(2)) were induced via suction on each participant's left and right forearm (randomized order; blister session 1 and 2), separated by approximately one week. Fluid was sampled from each blister, and the top layer of each blister was removed to reveal up to eight skin wounds. Fluid from each wound was collected 4, 7 and 24h after blisters were induced, and proinflammatory cytokines were measured. Transepidermal water loss (TEWL), to assess skin barrier recovery, was measured daily at each wound site until values were within 90% of baseline values (i.e., unbroken skin). Sleep, stress and inflammation (i.e., factors that affect wound healing and immune function), preceding the blister induction, were assessed via activity monitors (Actical, Philips Respironics, Murrysville, Pennsylvania), the Perceived Stress Scale (PSS) and C-reactive protein (CRP), respectively. Area-under-the-curve and TEWL, between blister session 1 and 2, were compared using Pearson correlations and partial correlations (controlling for average nightly sleep, PSS scores and CRP). The suction blister method was considered reliable for assessing immune response and skin barrier recovery if correlation coefficients reached 0.7. Volunteers (n=16; 12 M; 4F) were 23 ± 5 years [mean ± SD]. Time to skin barrier restoration was 4.9 ± 0.8 and 4.8 ± 0.9 days for sessions 1 and 2, respectively. Correlation coefficients for skin barrier restoration, IL-6, IL-8 and MIP-1α were 0.9 (P

Development of n‐3 fortified, shelf‐stable foods is facilitated by encapsulated docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), since natural n‐3 food sources cannot withstand high temperature and prolonged shelf life. Organoleptic stability of n‐3 fortified, shelf‐stable foods has been demonstrated, but chemical changes in the food matrix throughout storage could conceivably impact digestibility of the protein‐based encapsulant thereby compromising n‐3 bioavailability. We assessed the effect of prolonged high‐temperature storage and variations in food matrix (proteinaceous or carbohydrate) on the time course and magnitude of blood fatty acids changes associated with ingestion of n‐3 fortified foods. Low‐protein (i.e., cake) and high‐protein (i.e., meat sticks) items were supplemented with 600 mg encapsulated DHA+EPA, and frozen either immediately after production (FRESH) or after 6 months storage at 100°F (STORED). Fourteen volunteers consumed one item per week (randomized) for 4 weeks. Blood samples obtained at baseline, 2, 4, and 6 h post‐consumption were analyzed for circulating long‐chain omega 3 fatty acids (LCn3). There was no difference in LCn3 area under the curve between items. LCn3 in response to cakes peaked at 2‐h (FRESH: 54.0 ± 16.8 μg/mL, +18%; STORED: 53.0 ± 13.2 μg/mL, +20%), while meats peaked at 4‐h (FRESH: 51.9 ± 12.5 μg/mL, +22%; STORED: 53.2 ± 16.9 μg/mL, +18%). There were no appreciable differences in time course or magnitude of n‐3 appearance in response to storage conditions for either food types. Thus, bioavailability of encapsulated DHA/EPA, within low‐ and high‐protein food items, was not affected by high‐temperature shelf‐storage. A shelf‐stable, low‐ or high‐protein food item with encapsulated DHA/EPA is suitable for use in shelf‐stable foods.

Objective The US Army recruits new soldiers from an increasingly obese civilian population. The change in weight status at entry into the Army between 1989 and 2012 and the demographic characteristics associated with overweight/obesity at entry were examined. Methods 1,741,070 unique individuals with complete sex, age, and anthropometric information contributed data to linear and logistic regressions examining time trends and associations between demographic characteristics and overweight/obesity. Results The prevalence of overweight (body mass index 25

Cardiovascular (CV) and thermal responses to metabolically demanding multi-day military operations in extreme cold-weather environments are not well described. Characterization of these operations will provide greater insights into possible performance capabilities and cold injury risk. Soldiers from two cold-weather field training exercises (FTX) were studied during 3-day (study 1, n = 18, age: 20 ± 1 year, height: 182 ± 7 cm, mass: 82 ± 9 kg) and 4-day (study 2, n = 10, age: 20 ± 1 year, height: 182 ± 6 cm, mass: 80.7 ± 8.3 kg) ski marches in the Arctic. Ambient temperature ranged from −18 to −4 °C during both studies. Total daily energy expenditure (TDEE, from doubly labeled water), heart rate (HR), deep body (T pill), and torso (T torso) skin temperature (obtained in studies 1 and 2) as well as finger (T fing), toe (T toe), wrist, and calf temperatures (study 2) were measured. TDEE was 6821 ± 578 kcal day−1 and 6394 ± 544 for study 1 and study 2, respectively. Mean HR ranged from 120 to 140 bpm and mean T pill ranged between 37.5 and 38.0 °C during skiing in both studies. At rest, mean T pill ranged from 36.0 to 36.5 °C, (lowest value recorded was 35.5 °C). Mean T fing ranged from 32 to 35 °C during exercise and dropped to 15 °C during rest, with some T fing values as low as 6–10 °C. Ttoe was above 30 °C during skiing but dropped to 15–20 °C during rest. Daily energy expenditures were among the highest observed for a military training exercise, with moderate exercise intensity levels (~65% age-predicted maximal HR) observed. The short-term cold-weather training did not elicit high CV and T pill strain. T fing and T toe were also well maintained while skiing, but decreased to values associated with thermal discomfort at rest.

Military training studies provide unique insight into metabolic responses to extreme physiologic stress induced by multiple stressor environments, and the impacts of nutrition in mediating these responses. Advances in metabolomics have provided new approaches for extending current understanding of factors modulating dynamic metabolic responses in these environments. In this study, whole‐body metabolic responses to strenuous military training were explored in relation to energy balance and macronutrient intake by performing nontargeted global metabolite profiling on plasma collected from 25 male soldiers before and after completing a 4‐day, 51‐km cross‐country ski march that produced high total daily energy expenditures (25.4 MJ/day [SD 2.3]) and severe energy deficits (13.6 MJ/day [SD 2.5]). Of 737 identified metabolites, 478 changed during the training. Increases in 88% of the free fatty acids and 91% of the acylcarnitines, and decreases in 88% of the mono‐ and diacylglycerols detected within lipid metabolism pathways were observed. Smaller increases in 75% of the tricarboxylic acid cycle intermediates, and 50% of the branched‐chain amino acid metabolites detected were also observed. Changes in multiple metabolites related to lipid metabolism were correlated with body mass loss and energy balance, but not with energy and macronutrient intakes or energy expenditure. These findings are consistent with an increase in energy metabolism, lipolysis, fatty acid oxidation, ketogenesis, and branched‐chain amino acid catabolism during strenuous military training. The magnitude of the energy deficit induced by undereating relative to high energy expenditure, rather than macronutrient intake, appeared to drive these changes, particularly within lipid metabolism pathways.

The magnitude, temporal dynamics, and physiological effects of intestinal microbiome responses to physiological stress are poorly characterized. This study used a systems biology approach and a multiple-stressor military training environment to determine the effects of physiological stress on intestinal microbiota composition and metabolic activity, as well as intestinal permeability (IP). Soldiers ( n = 73) were provided three rations per day with or without protein- or carbohydrate-based supplements during a 4-day cross-country ski-march (STRESS). IP was measured before and during STRESS. Blood and stool samples were collected before and after STRESS to measure inflammation, stool microbiota, and stool and plasma global metabolite profiles. IP increased 62 ± 57% (mean ± SD, P < 0.001) during STRESS independent of diet group and was associated with increased inflammation. Intestinal microbiota responses were characterized by increased α-diversity and changes in the relative abundance of >50% of identified genera, including increased abundance of less dominant taxa at the expense of more dominant taxa such as Bacteroides. Changes in intestinal microbiota composition were linked to 23% of metabolites that were significantly altered in stool after STRESS. Together, pre-STRESS Actinobacteria relative abundance and changes in serum IL-6 and stool cysteine concentrations accounted for 84% of the variability in the change in IP. Findings demonstrate that a multiple-stressor military training environment induced increases in IP that were associated with alterations in markers of inflammation and with intestinal microbiota composition and metabolism. Associations between IP, the pre-STRESS microbiota, and microbiota metabolites suggest that targeting the intestinal microbiota could provide novel strategies for preserving IP during physiological stress.NEW & NOTEWORTHY Military training, a unique model for studying temporal dynamics of intestinal barrier and intestinal microbiota responses to stress, resulted in increased intestinal permeability concomitant with changes in intestinal microbiota composition and metabolism. Prestress intestinal microbiota composition and changes in fecal concentrations of metabolites linked to the microbiota were associated with increased intestinal permeability. Findings suggest that targeting the intestinal microbiota could provide novel strategies for mitigating increases in intestinal permeability during stress.

Background and aims: Due to the formation of strictures and fistulas, patients with Crohn’s disease (CD) frequently need surgery. Vitamin D has been found to play a role in the degree of inflammation. We aimed to study the effect of UV exposure on the need for inpatient surgery in patients with CD. Methods: The national inpatient sample, the largest database of hospitalizations from the USA, was used to conduct a retrospective study of patients hospitalized from 2004–2011 with CD by ICD-9CM code 555. Surgery was characterized as any intestinal surgery or fistula repair. An average state UV exposure was calculated for each hospitalization. Multivariate logistic regression was used to calculate the effect of UV exposure on surgery accounting for important covariates. Results: There were 481712 hospitalizations with a primary diagnosis of CD. Of these hospitalizations, 67751 included a relevant surgical procedure code. Mean UV exposure was statistically lower in the group undergoing surgery (4.3 units versus 4.4 units, p = 0.001). The ratio of hospitalizations per UV exposure tertile for CD was statistically different compared with all hospitalizations ( p < 0.001). In univariate analysis, increased UV exposure was associated with a lower risk of inpatient surgery with an OR of 0.90 per unit (95% CI 0.84–0.96, p = 0.001). Accounting for age, gender, race/ethnicity, season, income, hospital setting, and Charlson–Deyo comorbidities, the effect of UV exposure remained protective for inpatient surgery (OR 0.91, 95% CI: 0.84–0.98, p = 0.01). Conclusions: Increased UV exposure is associated with a reduced risk of inpatient surgery among patients with CD. Further studies of vitamin D’s role in CD are necessary. * Abbreviations : CD : Crohn’s disease UV : Ultraviolet NIS : National Inpatient Sample IBD : inflammatory bowel disease UC : ulcerative colitis

Physiological consequences of winter military operations are not well described. This study examined Norwegian soldiers (n = 21 males) participating in a physically demanding winter training program to evaluate whether short-term military training alters energy and whole-body protein balance, muscle damage, soreness, and performance. Energy expenditure (D218O) and intake were measured daily, and postabsorptive whole-body protein turnover ([15N]-glycine), muscle damage, soreness, and performance (vertical jump) were assessed at baseline, following a 4-day, military task training phase (MTT) and after a 3-day, 54-km ski march (SKI). Energy intake (kcal·day−1) increased (P < 0.01) from (mean ± SD (95% confidence interval)) 3098 ± 236 (2985, 3212) during MTT to 3461 ± 586 (3178, 3743) during SKI, while protein (g·kg−1·day−1) intake remained constant (MTT, 1.59 ± 0.33 (1.51, 1.66); and SKI, 1.71 ± 0.55 (1.58, 1.85)). Energy expenditure increased (P < 0.05) during SKI (6851 ± 562 (6580, 7122)) compared with MTT (5480 ± 389 (5293, 5668)) and exceeded energy intake. Protein flux, synthesis, and breakdown were all increased (P < 0.05) 24%, 18%, and 27%, respectively, during SKI compared with baseline and MTT. Whole-body protein balance was lower (P < 0.05) during SKI (–1.41 ± 1.11 (–1.98, –0.84) g·kg−1·10 h) than MTT and baseline. Muscle damage and soreness increased and performance decreased progressively (P < 0.05). The physiological consequences observed during short-term winter military training provide the basis for future studies to evaluate nutritional strategies that attenuate protein loss and sustain performance during severe energy deficits.

Understanding the nutritional demands on serving military personnel is critical to inform training schedules and dietary provision. Troops deployed to Afghanistan face austere living and working environments. Observations from the military and those reported in the British and US media indicated possible physical degradation of personnel deployed to Afghanistan. Therefore, the present study aimed to investigate the changes in body composition and nutritional status of military personnel deployed to Afghanistan and how these were related to physical fitness. In a cohort of British Royal Marines (n249) deployed to Afghanistan for 6 months, body size and body composition were estimated from body mass, height, girth and skinfold measurements. Energy intake (EI) was estimated from food diaries and energy expenditure measured using the doubly labelled water method in a representative subgroup. Strength and aerobic fitness were assessed. The mean body mass of volunteers decreased over the first half of the deployment ( − 4·6 (sd3·7) %), predominately reflecting fat loss. Body mass partially recovered (mean +2·2 (sd2·9) %) between the mid- and post-deployment periods (Psd3339) kJ) was significantly lower than the estimated daily energy expenditure (mean 15 167 (sd1883) kJ) measured in a subgroup of volunteers. However, despite the body mass loss, aerobic fitness and strength were well maintained. Nutritional provision for British military personnel in Afghanistan appeared sufficient to maintain physical capability and micronutrient status, but providing appropriate nutrition in harsh operational environments must remain a priority.

Special Operations Forces (SOF) regularly engage in physically demanding combat operations and field training exercises, resulting in high daily energy expenditure, and thus increased energy requirements. However, the majority of studies assessing energy requirements of SOF have been conducted on soldiers going through intense SOF initiation training. The objective of the current investigation was to determine the energy expenditure of SOF conducting military training operations. Thirty-one soldiers taking part in Pre-Mission Training (PMT n = 15) and Combat Diver Qualification Courses (CDQC n = 16) volunteered to participate in this observational study. Energy expenditure was determined using doubly labeled water. Body weight (83 ± 7 kg) remained stable during both training periods. Overall energy expenditure adjusted for body composition was 17,606 ± 2326 kJ·day(-1). Energy expenditure was 19,110 ± 1468 kJ·day(-1) during CDQC and 16,334 ± 2180 kJ·day(-1) during PMT, with physical activity levels of 2.6 ± 0.2 and 2.2 ± 0.3 during CDQC and PMT, respectively. Compared to the Military Dietary Reference Intakes for energy (13,598 kJ·day(-1)), these data are in agreement with previous reports that energy requirement for SOF Soldiers exceed that of the average soldier.

BACKGROUND It has been proposed that microclimate cooling systems exploit the peripheral extremities because of more efficient heat transfer. The purpose of this study was to quantify, using a patented microclimate cooling technique, the heat transfer from the plantar surface of the foot for comparison to other commonly cooled body regions. METHODS A military boot was fitted with an insole embedded with a coiled, 1.27 m length of hollow tubing terminating in inlet and outlet valves. A thermal foot manikin with a surface temperature of 34 degrees C was placed in the boot and the valves were connected to a system that circulated water through the insole at a temperature of 20 degrees C and flow rate of 120 ml x min(-1). The manikin foot served as a constant heat source to determine heat transfer provided by the insole. Testing was done with the foot model dry and sweating at a rate of 500 ml x h(- 1) x m(-2). Climatic chamber conditions were 30 degrees C with 30% RH. RESULTS Heat loss was approximately 4.1 +/- 0.1 and approximately 7.7 +/- 0.3 W from the dry and sweating foot models, respectively. On a relative scale, the heat loss was 3.0 W and 5.5 W per 1% (unit) body surface area, respectively, for the dry and sweating conditions. DISCUSSION The relative heat loss afforded by plantar foot cooling was similar compared to other body regions, but the absolute amount of heat removal is unlikely to make an impact on whole body heat balance.

OBJECTIVES: Recent studies have reported altered fecal microbiota composition together with increased intestinal permeability (IP) and inflammation in individuals consuming military food rations in austere environments, but could not separate effects of the highly processed, commercially sterile ration-based diets from environmental factors. This study aimed to determine how the U.S. Meal, Ready-to-Eat (MRE) food ration affects fecal microbiota composition and IP. METHODS: In this parallel-arm trial, 60 adults (95% male, 18–61 yr) were randomly assigned to consume their usual diet for 31d (CON), or a strictly controlled MRE-only diet for 21d then their usual diet for 10d (MRE). Fecal samples were collected at baseline (BL, days -8–0), and during (INT, days 1–21) and after (POST, days 22–31) the intervention period to measure microbiota composition by 16S rDNA sequencing. On days 0, 10, 21 and 31 IP was measured by dual-sugar absorption test, and circulating markers of bacterial translocation from the gut lumen (LPS-binding protein (LBP)) and inflammation (hsCRP) were measured. RESULTS: During INT, carbohydrate (CON vs MRE: 44% vs 50% energy) and fiber (19 vs 26 g/d) intakes were lower in CON relative to MRE, whereas protein intake was higher (18% vs. 13% energy) (P ≤ 0.01). Body weight increased over time in CON, but transiently decreased during INT in MRE (P = 0.001). Changes in fecal microbiota composition differed over time between groups (P ≤ 0.01), with random forest models discriminating the fecal microbiota of MRE and CON samples during INT with 88% accuracy. The most discriminant genera included multiple bacteria used in food production (Lactobacillus, Lactococcus, Streptococcus, Leuconostoc) which were less abundant in MRE, and the inflammation-associated genus Sutterella which transiently increased in MRE during INT. IP and hsCRP were both lower (25% and 16%, respectively) in MRE relative to CON on day 21 (P

Core temperature (CT) in combination with heart rate (HR) can be a good indicator of impending heat exhaustion for occupations involving exposure to heat, heavy workloads, and wearing protective clothing. However, continuously measuring CT in an ambulatory environment is difficult. To address this problem we developed a model to estimate the time course of CT using a series of HR measurements as a leading indicator using a Kalman filter. The model was trained using data from 17 volunteers engaged in a 24 h military field exercise (air temperatures 24–36 °C, and 42%–97% relative humidity and CTs ranging from 36.0–40.0 °C). Validation data from laboratory and field studies (N = 83) encompassing various combinations of temperature, hydration, clothing, and acclimation state were examined using the Bland–Altman limits of agreement (LoA) method. We found our model had an overall bias of −0.03 ± 0.32 °C and that 95% of all CT estimates fall within ±0.63 °C (>52 000 total observations). While the model for estimating CT is not a replacement for direct measurement of CT (literature comparisons of esophageal and rectal methods average LoAs of ±0.58 °C) our results suggest it is accurate enough to provide practical indication of thermal work strain for use in the work place.

Objective: Energy density (ED) and eating rate (ER) influence energy intake; their combined effects on intake and on postprandial pancreatic and gut hormone responses are undetermined. To determine the combined effects of ED and ER manipulation on voluntary food intake, subjective appetite, and postprandial pancreatic and gut hormone responses. Design and Methods: Twenty nonobese volunteers each consumed high (1.6 kcal g−1; HED) and low (1.2 kcal g−1; LED) ED breakfasts slowly (20 g min−1; SR) and quickly (80 g min−1; FR) ad libitum to satiation. Appetite, and pancreatic and gut hormone concentrations were measured periodically over 3 h. Ad libitum energy intake during the subsequent lunch was then measured. Results: Main effects of ED and ER on energy intake and a main effect of ER, but not ED, on mass of food consumed were observed, FR and HED being associated with increased intake (P < 0.05). Across all conditions, energy intake was highest during FR-HED (P ≤ 0.01). Area under the curve (AUC) of appetite ratings was not different between meals. Main effects of ED and ER on insulin, peptide-YY, and glucagon-like peptide-1 AUC (P < 0.05) were observed, FR and HED being associated with larger AUC. No effects on active or total ghrelin AUC were documented. Total energy intake over both meals was highest during the FR-HED trial with the greatest difference between FR-HED and SR-LED trials (P ≤ 0.01). Conclusion: Consuming an energy dense meal quickly compounds independent effects of ER and ED on energy intake. Energy compensation at the following meal may not occur despite altered gut hormone responses.

What is the topic of this review? There is a need to revisit the basic principles of exercise mass and water balance, the use of common equations and the practice of interpreting outcomes. What advances does it highlight? We propose use of the following equation as a way of simplifying exercise mass and water balance calculations in conditions where food is not consumed and waste is not excreted: ∆body mass - 0.20 g/kcal