Doubly-labelled Water Technique Research Articles

Energetics and Water Flux in the Subterranean Rodent Family Bathyergidae

The doubly labeled water (DLW) technique and indirect calorimetry enable measurement of an animal’s daily energy expenditure (DEE, kJ/day), resting metabolic rate (RMR, kJ/d), sustained metabolic scope (SusMS), body fat content (BF, %) as well as water turnover (WTO, ml/day), and water economy index (ml/kJ). Small mammals have been the primary focus of many of the DLW studies to date. From large multi-species analyses of the energetics and water flux of aboveground small mammals, well-defined trends have been observed. These trends mainly refer to an adaptive advantage for lower RMR, DEE, SusMS, WTO and WEI in more ariddwelling animals to increase water and energy savings under low and unpredictable resource availability. The study of the subterranean rodent family Bathyergidae (African mole-rats) has been of particular interest with regards to field metabolic rate and metabolic studies. Although a great deal of research has been conducted on the Bathyergidae, a complete overview and multi-species analysis of the energetics and water flux of this family is lacking. Consequently, we assessed DEE, RMR, SusMS, BF, WTO and WEI across several different species of bathyergids from various climatic regions, and compared these to the established patterns of energetics and water flux for aboveground rodents. There was notable variation across the Bathyergidae inhabiting areas with different aridities, often contrary to the variations observed in above-ground species. These include increased DEE and WEI in arid-dwelling bathyergid species. While the climate was not a clear factor when predicting the SusMS of a bathyergid species, rather the degree of group living was a strong driver of SusMS, with solitary species possessing the highest SusMS compared to the socially living species. We conclude that the constraints of the underground lifestyle and the consequent spectrum of social behaviors possessed by the family Bathyergidae are most likely to be more crucial to their energetics and water flux than their habitat; however other important unstudied factors may still be at play. More so, this study provides evidence that often unreported parameters, measured through use of the DLW technique (such as BF and WEI) can enable species to be identified that might be at particular risk to climate change.

Validation of accelerometer-based energy expenditure equations using doubly-labelled water technique in 11-13 year-old Sri Lankan children

The Journal is the primary organ of Continuing Paediatric Medical Education in Sri Lanka. The journal also has a website. Free full text access is available for all readers.The Sri Lanka Journal of Child Health is now indexed in SciVerse Scopus (Source Record ID 19900193609), Index Medicus for South-East Asia Region (IMSEAR), CABI (Centre for Agriculture and Bioscience International Global Health Database), DOAJ and is available in Google, as well as Google Scholar.The policies of the journal are modelled on the Committee on Publication Ethics (COPE) Guidelines on Principles of Transparency and Best Practice in Scholarly Publishing. Sri Lanka Journal of Child Health is recognised by the International Committee of Medical Journal Editors (ICMJE) as a publication following the ICMJE Recommendations.

Estimated Energy Requirements of Infants and Young Children up to 24 Months of Age.

ABSTRACTBackgroundEstablishing energy requirements in infants and young children is important in developing age-appropriate diet recommendations but most published guidelines for energy requirements have 1 or more limitations related to the data underlying the calculations.ObjectiveTo develop a comprehensive set of daily energy requirements for infants and young children aged 0–24 mo meeting the ideals of worldwide applicability to all healthy children based on the use of the doubly labeled water (DLW) technique to measure total energy expenditure (TEE), the use of recent, international growth charts, and calculation of values across a wide range of body weight.MethodsDaily estimated energy requirements (EERs) were calculated in 1-mo increments from 0 to 24 mo for boys, girls, and combined, using as inputs the following: 1) TEE measured using the DLW technique, 2) energy deposition estimates from the Institute of Medicine, and 3) body weight values from the 25th to 75th percentiles from the 2006 WHO growth charts. EERs were combined for age groups 0 to <6, 6–8, 9–11, and 12–24 mo by averaging EERs from individual months. The EER calculations were supported by a systematic literature review and a meta-regression of existing studies.ResultsEnergy requirements naturally increase with age and are slightly higher in boys than in girls. The EERs derived in this study are similar to those in other recent international efforts.ConclusionsThis updated set of EERs for infants and young children expand and improve upon the methodology used to establish previous published guidelines. These estimates have multiple potential uses including planning age-appropriate menus for the complementary feeding period, the development of foods that are more precisely targeted to the needs of infants and children at particular ages, and establishing macronutrient requirements within specific age groups based on a percentage of energy, such as dietary fat.

Daily energy expenditure and water turnover in two breeds of laying hens kept in floor housing

Laying hens are increasingly kept in barn or free-range systems, which not only allows birds to move freely but also potentially entails higher energy expenditures due to higher locomotor activity. Therefore, the aim of our study was to quantify the daily energy expenditure (DEE) and water turnover in freely moving laying hens. For that purpose, 10 Lohmann Selected Leghorn (LSL) and 10 Lohmann Brown (LB) hens were obtained from a conventional breeding company at 17 weeks of age. The trial started when birds reached an age of 34 weeks. All 20 birds were kept together in the same littered floor pen (12.1 m2). The pen was equipped with perches, a nest box, feeding and nipple drinkers. The DEE was determined individually for all experimental birds (n = 20) for a total of nine days using the doubly labelled water (DLW) method. Lohmann Brown hens were heavier than LSL hens, but laying rate did not differ between the two breeds, that is, one egg per hen and day during the study period. Average egg mass was 63.1 ± 0.20 g in LB and 61.7 ± 0.12 g in LSL hens, which converted to an egg energy content of 420 and 410 kJ/egg, respectively. Dilution spaces for oxygen and hydrogen differed between the breeds but not the respective turnover rates. Total body water as a percentage of body mass (LB: 54.4%, LSL: 53.8%; SEM = 0.7, F1,18 = 0.41, P = 0.513) and total water intake (TWI) per day (LB: 275 ml/day, LSL: 276 ml/day; SEM = 20, F1,17 = 0, P = 0.994) did not differ between LB and LSL hens. Individual DEE increased with body mass in LB but not in LSL hens. Average DEE did not differ between the two breeds (LB: 1501 kJ/day; LSL: 1520 kJ/day; SEM = 32.1, F1,17 = 2.54, P = 0.131). However, when comparing the DEE on a metabolic mass basis, LSL hens expended with 984 kJ/kg0.75 on average significantly more energy per day than LB hens (895 kJ/kg0.75; SEM = 20.3, F1,18 = 10.1, P = 0.005). Our results suggest that the DLW technique is a viable method to measure the energy expenditure and water turnover over several days in laying hens. Furthermore, we show that laying hens kept in floor pens fit into the general pattern of DEE among wild birds.

Validity of Dietary Assessment Methods When Compared to the Method of Doubly Labeled Water: A Systematic Review in Adults

Accuracy in quantifying energy intake (EI) using common dietary assessment methods is crucial for interpreting the relationship between diet and chronic disease. The aim of this systematic review was to evaluate the validity of dietary assessment methods used to estimate the EI of adults in comparison to total energy expenditure (TEE) measured by doubly labeled water (DLW). Articles in English across nine electronic databases, published between 1973 and February 2019 were retrieved. Studies were included if participants were adults (≥18 years) and used the DLW technique to measure TEE compared to self-reported EI. A total of 59 studies were included, with a total of 6,298 free living adults and a mean of 107 participants per study. The majority of studies including 16 studies that included a technology based method reported significant (P < 0.05) under-reporting of EI when compared to TEE, with few over-reporting EI. Misreporting was more frequent among females compared to males within recall based dietary assessment methods. The degree of under-reporting was highly variable within studies using the same method, with 24 h recalls having less variation and degree of under-reporting compared to other methods.

Prediction Equation For Estimating Total Daily Energy Requirements Of Special Operations Personnel

Special Operations Forces (SOF) engage in a variety of military tasks with many producing high energy expenditures, resulting in undesired energy deficits and loss of body mass. Therefore, the ability to accurately estimate daily energy requirements would be useful to generate adequate feeding regimens to support maintenance of energy balance during military operations. PURPOSE: Generate a predictive equation estimating energy requirements of SOF. METHODS: Retrospective analysis of data collected from SOF personnel engaged in 12 different SOF training scenarios. Energy expenditure and total body water were determined using the doubly-labeled water (DLW) technique. Physical activity level was determined as daily energy expenditure divided by resting metabolic rate. Physical activity level was broken into quartiles (0 = mission prep, 1 = common warrior tasks, 2 = battle drills, 3 = specialized intense activity) to generate a physical activity factor (PAF). Regression analysis was used to construct two predictive equations (Model A; body mass and PAF, Model B; fat-free mass and PAF) estimating daily energy expenditures. RESULTS: Average measured energy expenditure during SOF training was 4468 (range: 3700 to 6300) Kcal·d-1. Regression analysis revealed that physical activity level (r = 0.91; P < 0.05) and body mass (r = 0.28; P < 0.05; Model A), or fat-free mass (FFM; r = 0.32; P < 0.05; Model B) were the factors that most highly predicted energy expenditures. Predictive equations coupling PAF with body mass (Model A) and FFM (Model B), were correlated (r = 0.74 and r = 0.76, respectively) and did not differ (mean ± SEM: Model A; 4463 ± 65 Kcal·d-1, Model B; 4462 ± 61 Kcal·d-1) from DLW measured energy expenditures. CONCLUSION: By quantifying and grouping SOF training exercises into activity factors, SOF energy requirements can be predicted with reasonable accuracy and these equations can be used by dietetic/logistical personnel to plan appropriate feeding regimens to meet SOF nutritional requirements across their various mission profile. Disclaimer: The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of Army, Department of Defense, or the U.S. Government.

Energy Intake Derived from an Energy Balance Equation, Validated Activity Monitors, and Dual X-Ray Absorptiometry Can Provide Acceptable Caloric Intake Data among Young Adults

Assessments of energy intake (EI) are frequently affected by measurement error. Recently, a simple equation was developed and validated to estimate EI on the basis of the energy balance equation [EI = changed body energy stores + energy expenditure (EE)]. The purpose of this study was to compare multiple estimates of EI, including 2 calculated from the energy balance equation by using doubly labeled water (DLW) or activity monitors, in free-living adults. The body composition of participants (n = 195; mean age: 27.9 y; 46% women) was measured at the beginning and end of a 2-wk assessment period with the use of dual-energy X-ray absorptiometry. Resting metabolic rate (RMR) was calculated through indirect calorimetry. EE was assessed with the use of the DLW technique and an arm-based activity monitor [Sensewear Mini Armband (SWA); BodyMedia, Inc.]. Self-reported EI was calculated by using dietitian-administered 24-h dietary recalls. Two estimates of EI were calculated with the use of a validated equation: quantity of energy stores estimated from the changes in fat mass and fat-free mass occurring over the assessment period plus EE from either DLW or the SWA. To compare estimates of EI, reporting bias (estimated EI/EE from DLW × 100) and Goldberg ratios (estimated EI/RMR) were calculated. Mean ± SD EEs from DLW and SWA were 2731 ± 494 and 2729 ± 559 kcal/d, respectively. Self-reported EI was 2113 ± 638 kcal/d, EI derived from DLW was 2723 ± 469 kcal/d, and EI derived from the SWA was 2720 ± 730 kcal/d. Reporting biases for self-reported EI, DLW-derived EI, and SWA-derived EI are as follows: -21.5% ± 22.2%, -0.7% ± 18.5%, and 0.2% ± 20.8%, respectively. Goldberg cutoffs for self-reported EI, DLW EI, and SWA EI are as follows: 1.39 ± 0.39, 1.77 ± 0.38, and 1.77 ± 0.38 kcal/d, respectively. These results indicate that estimates of EI based on the energy balance equation can provide reasonable estimates of group mean EI in young adults. The findings suggest that, when EE derived from DLW is not feasible, an activity monitor that provides a valid estimate of EE can be substituted for EE from DLW.

Effect of reduced protein intake on endurance performance and water turnover during low intensity long duration exercise in Alaskan sled dogs

Increased nutritional demands for endurance exercise of dogs are typically met through increased amounts of their current food. As a result, protein intake is also increased, and excessive nitrogen may affect the dog’s water balance. Sixteen unconditioned Alaskan sled dogs underwent a 6-week exercise training protocol, wherein 8 dogs were fed increasing amounts of their normal kibble to maintain body weight, while the other 8 were fed the same amount of kibble, with increasing calorie needs met by equal amounts of sugar and oil. The diets resulted in similar calorie intakes (181.3±20.0 and 205.7±36.3 kcal/kg0.75, for the control and low protein dogs respectively) but control dogs had higher protein intakes (32.2±0.0 and 19.4±2.4% of metabolic energy intake). After 6 weeks of training the dogs completed a 5 day exercise test in which they travelled 24 km per day, where total energy expenditure was determined using doubly-labelled water technique. Dogs expended an average of 1,491±264 kcal/day (145±25 kcal/kg0.75/day), with no difference between the dietary treatments and no negative performance indicators. Following the exercise test the dogs underwent a 24 hour dehydration test (water withheld) followed by an 8 hour rehydration test (with ad libitum water intake recorded) where total body water was determined using deuterium oxide. Blood and urinary samples were also collected. Following exercise conditioning, control dogs had higher serum urea nitrogen than low protein dogs, and this as well as albumin decreased further during the 5 day exercise test. Low-protein dogs had lower overall total body water and higher fractional excretion of Na+, suggesting some renal adaptation. These findings suggest that reduced protein intake did not negatively affect athletic performance, though some facets of body chemistry were altered.

Prediction equation for estimating total daily energy requirements of special operations personnel

BackgroundSpecial Operations Forces (SOF) engage in a variety of military tasks with many producing high energy expenditures, leading to undesired energy deficits and loss of body mass. Therefore, the ability to accurately estimate daily energy requirements would be useful for accurate logistical planning.PurposeGenerate a predictive equation estimating energy requirements of SOF.MethodsRetrospective analysis of data collected from SOF personnel engaged in 12 different SOF training scenarios. Energy expenditure and total body water were determined using the doubly-labeled water technique. Physical activity level was determined as daily energy expenditure divided by resting metabolic rate. Physical activity level was broken into quartiles (0 = mission prep, 1 = common warrior tasks, 2 = battle drills, 3 = specialized intense activity) to generate a physical activity factor (PAF). Regression analysis was used to construct two predictive equations (Model A; body mass and PAF, Model B; fat-free mass and PAF) estimating daily energy expenditures.ResultsAverage measured energy expenditure during SOF training was 4468 (range: 3700 to 6300) Kcal·d-1. Regression analysis revealed that physical activity level (r = 0.91; P < 0.05) and body mass (r = 0.28; P < 0.05; Model A), or fat-free mass (FFM; r = 0.32; P < 0.05; Model B) were the factors that most highly predicted energy expenditures. Predictive equations coupling PAF with body mass (Model A) and FFM (Model B), were correlated (r = 0.74 and r = 0.76, respectively) and did not differ [mean ± SEM: Model A; 4463 ± 65 Kcal·d− 1, Model B; 4462 ± 61 Kcal·d− 1] from DLW measured energy expenditures.ConclusionBy quantifying and grouping SOF training exercises into activity factors, SOF energy requirements can be predicted with reasonable accuracy and these equations used by dietetic/logistical personnel to plan appropriate feeding regimens to meet SOF nutritional requirements across their mission profile.

Surveying predictors of late-life longitudinal change in daily activity energy expenditure.

BackgroundTotal daily energy expenditure (TEE) is composed of resting metabolic rate (RMR), post-prandial thermogenesis and activity energy expenditure (AEE). Higher AEE is strongly associated with lower mortality and physical limitations among older adults, but factors that predict changes in AEE in septu and octogenarians are not clearly understood.ObjectiveTo identify factors associated with late-life longitudinal change in AEE.DesignEnergy expenditure was re-assessed in 83 participants (average age at baseline, 74.4±3.2 years)—an average of 7.5±0.54 years since the baseline measure. RMR was measured using indirect calorimetry and the thermic effect of meals was estimated at 10% of TEE. AEE was calculated as: TEE(0.9)-RMR. Participants were categorized into two groups according to the estimated day-to-day precision of the doubly-labeled water technique. Those who were within 10% or increased relative to their initial AEE measurement were categorized as having preserved AEE. Participants who declined greater than 10% of their initial measurement were categorized as having reduced AEE. A variety of socio-demographic, functional and mental factors, body composition, community and personal behaviors, blood measurements and health conditions were evaluated between groups at baseline and changes during follow-up.ResultsDaily AEE declined 106.61±293.25 kcal, which equated to a 14.63±40.57 kcal/d decrease per year. Fifty-nine percent (n = 49) preserved their AEE and 41% (n = 34) declined. Those who demonstrated a decline in AEE were older, had lower walking speed at baseline and showed a higher lean mass loss during follow up. Otherwise, groups were similar for socio-demographic characteristics, body composition, mental and physical function, health conditions and community and personal behaviors at baseline and change in these factors during follow-up.ConclusionsThis study demonstrates that AEE declines through the 8th decade of life and is associated with age, lower walking speed at baseline and lean mass loss. Additionally, there are a significant number of individuals who appear to be resilient to these declines despite having health events that are expected to have a negative impact on their physical activity.

Evaluation Of Energy Intake At A Range Of Energy Flux Derived From Self-report, Doubly Labeled Water, And Activity Monitors

PURPOSE: Self-report estimates of energy intake (EI) are adversely affected by measurement error. Recently, a simple equation has been developed and validated to estimate EI based on the energy balance equation (EI= energy storage + energy expenditure). Our goal was to compare self-report estimates of EI against two alternative values calculated from the energy balance equation. METHODS: Body composition of participants (N=195, mean age= 27.9 years, 46% female) was measured at the beginning and end of a two-week assessment period using dual-energy X-ray absorptiometry. Resting metabolic rate (RMR) was measured by indirect calorimetry. Energy expenditure (EE) was assessed using the doubly-labeled water technique and an arm-based activity monitor (Sensewear® Mini, SWA). Self-reported EI was calculated using dietician-administered 24-hour dietary recalls (three days, including at least one weekend day). Two estimates of EI were calculated using a validated equation: energy equivalent of changes in fat mass and fat-free mass occurring over the assessment period, plus EE from either DLW or SWA. To evaluate estimates of EI, reporting bias ((estimated EI - EE from DLW)/EE from DLW x 100) and Goldberg Cut-offs (estimated EI/RMR) were calculated. RESULTS: Mean±SD EE values from DLW and SWA were 2731±494 and 2729±559 kcals/day, respectively. Self-reported EI was 2113±638 kcals/day, EI derived from DLW was 2723±469, and EI derived from SWA was 2720±730. Reporting bias for self-reported EI, DLW EI, and SWA EI are as follows: -21.5±22.2%, -0.7±18.5%, and 0.2±20.8%, respectively. Goldberg Cut-offs for self-reported EI, DLW EI, and SWA EI are as follows: 1.39±0.39, 1.77±0.38, 1.77±0.38, respectively. When examined by tertiles of EE, bias of EI derived from self-report, DLW, and SWA varied between low (-17.4±27.5%, -2.9±18.1%, and 4.5±22.3%, respectively) and high groups (-25.6±19.5%, 0.4±17.5%, -4.4±17.6%, respectively). CONCLUSION: These results suggest that estimates of EI based on the energy balance equation can provide reasonable estimates of group mean EI. When compared by different levels of energy flux, estimates from all methods varied by EE level, indicating a potential source of bias that requires further investigation.

Energy intake and expenditure of improvised explosive device detection dogs

Improvised explosive device detection (IDD) dogs explore up to 40 km of land daily and therefore have energetic demands that may be above the National Research Council’s requirement for working dogs. This study was designed to quantify metabolic energy intake (MEI) and total energy expenditure (TEE) in a group of IDD dogs. Two groups of dogs that had undergone different training protocols (CP1, n=8 and CP2, n=11) underwent a 5-day deployment simulation that consisted of combined road clearing, orbit and point-to-point activities and lasted approximately 9 h per day. The CP1 dogs were fed according to the IDD Marine Corps Manual, while CP2 dogs were offered additional calories based on pilot study data of energy expenditure. The MEI was calculated based on feed intake rates and chemical composition of the diets. TEE was quantified using the doubly-labelled water technique in 2 of the CP1 dogs and 7 of the CP2 dogs. During the 5-day deployment simulation the MEI ranged from 189-310 kcal/bodyweight (BW)0.75 per day, with the CP2 dogs at the higher end because they were offered more feed. The TEE ranged between 375-507 kcal/BW0.75 per day, above the MEI, suggesting the dogs were in negative energy balance and metabolic reserves within the body were combusted for energy production. These findings reveal that energy requirements of deployed military working dogs are higher than previously published metabolic energy requirements of working dogs.

Evaluation of a Mobile Phone Image-Based Dietary Assessment Method in Adults with Type 2 Diabetes.

Image-based dietary records have limited evidence evaluating their performance and use among adults with a chronic disease. This study evaluated the performance of a 3-day mobile phone image-based dietary record, the Nutricam Dietary Assessment Method (NuDAM), in adults with type 2 diabetes mellitus (T2DM). Criterion validity was determined by comparing energy intake (EI) with total energy expenditure (TEE) measured by the doubly-labelled water technique. Relative validity was established by comparison to a weighed food record (WFR). Inter-rater reliability was assessed by comparing estimates of intake from three dietitians. Ten adults (6 males, age: 61.2 ± 6.9 years old, BMI: 31.0 ± 4.5 kg/m2) participated. Compared to TEE, mean EI (MJ/day) was significantly under-reported using both methods, with a mean ratio of EI:TEE 0.76 ± 0.20 for the NuDAM and 0.76 ± 0.17 for the WFR. Correlations between the NuDAM and WFR were mostly moderate for energy (r = 0.57), carbohydrate (g/day) (r = 0.63, p < 0.05), protein (g/day) (r = 0.78, p < 0.01) and alcohol (g/day) (rs = 0.85, p < 0.01), with a weaker relationship for fat (g/day) (r = 0.24). Agreement between dietitians for nutrient intake for the 3-day NuDAM (Intra-class Correlation Coefficient (ICC) = 0.77–0.99) was lower when compared with the 3-day WFR (ICC = 0.82–0.99). These findings demonstrate the performance and feasibility of the NuDAM to assess energy and macronutrient intake in a small sample. Some modifications to the NuDAM could improve efficiency and an evaluation in a larger group of adults with T2DM is required.

Doubly Labeled Water Is a Validated and Verified Reference Standard in Nutrition Research

Doubly Labeled Water Is a Validated and Verified Reference Standard in Nutrition Research

Energy Expenditure Compared to Physical Activity Measured by Accelerometry and Self-Report in Adolescents: A Validation Study

BackgroundPhysical inactivity is responsible for 5.3 million deaths annually worldwide. To measure physical activity energy expenditure, the doubly labeled water (DLW) method is the gold standard. However, questionnaires and accelerometry are more widely used. We compared physical activity measured by accelerometer and questionnaire against total (TEE) and physical activity energy expenditure (PAEE) estimated by DLW.MethodsTEE, PAEE (TEE minus resting energy expenditure) and body composition were measured using the DLW technique in 25 adolescents (16 girls) aged 13 years living in Pelotas, Brazil. Physical activity was assessed using the Actigraph accelerometer and by self-report. Physical activity data from accelerometry and self-report were tested against energy expenditure data derived from the DLW method. Further, tests were done to assess the ability of moderate-to-vigorous intensity physical activity (MVPA) to predict variability in TEE and to what extent adjustment for fat and fat-free mass predicted the variability in TEE.ResultsTEE varied from 1,265 to 4,143 kcal/day. It was positively correlated with physical activity (counts) estimated by accelerometry (rho = 0.57; p = 0.003) and with minutes per week of physical activity by questionnaire (rho = 0.41; p = 0.04). An increase of 10 minutes per day in moderate-to-vigorous intensity physical activity (MVPA) relates to an increase in TEE of 141 kcal/day. PAEE was positively correlated with accelerometry (rho = 0.64; p = 0.007), but not with minutes per week of physical activity estimated by questionnaire (rho = 0.30; p = 0.15). Physical activity by accelerometry explained 31% of the vssariability in TEE. By incorporating fat and fat-free mass in the model, we were able to explain 58% of the variability in TEE.ConclusionObjectively measured physical activity significantly contributes to the explained variance in both TEE and PAEE in Brazilian youth. Independently, body composition also explains variance in TEE, and should ideally be taken into account when using accelerometry to predict energy expenditure values.

Validity of the doubly labeled water method for estimating CO2production in mice under different nutritional conditions

The doubly labeled water (DLW) technique is used to assess metabolic rate (MR) in free-living conditions. We investigated whether differences in the nutritional and body adiposity status affect validity of the assessment of CO2 production (rCO2) by the DLW technique. To serve this purpose, we compared calculated rCO2 by the DLW method to actual CO2 production concomitantly measured in an indirect calorimetry setup over a 3-day period in mice fed with a low-fat (LF) diet or an obesogenic high-fat/high-sucrose (HF) diet. To uncover a potential effect of body composition on DLW accuracy, the HF-fed group was further subdivided in a diet-induced obesity-prone (DIO) and diet-induced obesity-resistant (DR) group. Furthermore, we assessed the influence of different sampling protocols, duration, and methodology of calculation. An excellent match was found between rCO2 assessed by the two methods in the LF-fed mice (least discrepancy -0.5 ± 1.1%). In contrast, there was a consistent overestimation of rCO2 by the DLW technique in the HF-fed animals compared with actual CO2 production independent from body mass gain (least discrepancy DR +15.9 ± 2.2%, DIO +18.5 ± 3.2%). The least discrepancies were found when two-pool model equations and the intercept method were used to calculate the body water pool. Furthermore, the HF group presented different equilibration kinetics of (2)H and (18)O and a lower dilution space ratio between the two. We recommend particular caution when using the DLW method for MR assessment in HF-fed animals and potentially humans because of the overestimation of rCO2.

Daily energy expenditure in the pouched mouse (Saccostomus campestris Peters 1896)

ABSTRACT Previous studies of the pouched mouse (Saccostomus campestris) have revealed that during reproduction there is no increase in food consumption, although resting energy demands, measured by respirometry, increase substantially. One explanation for this anomalous situation is that these mice may routinely use torpor to compensate their energy budgets. We measured the daily energy expenditure of eleven individual pouched mice over three consecutive days using the doubly-labelled water technique. The mice were housed in cages where they had free access to food and water, at an average temperature of 26.5 °C, and exposed to a natural photoperiod (February Pretoria). There was a large day-to-day variation in energy expenditure within each individual. The coefficient of variation in daily energy demand averaged 24.5%. By comparing the correlation of estimates for consecutive and nonconsecutive days we established that this variation was not a consequence of errors in the isotopic technique. The scaling ...

Can a web‐based food record accurately assess energy intake in overweight and obese women? A pilot study

Innovative dietary intake measurement tools, such as web-based food records, are becoming increasingly available for self-monitoring. However, the accuracy of this method has not been well studied. This pilot study aimed to evaluate the accuracy of energy intake (EI) estimated by a web-based food record, by comparison with total energy expenditure (TEE) measured by doubly-labelled water (DLW) in overweight and obese women. Total energy expenditure (TEE) was assessed in weight stable (±1 kg) women (n = 9), with a mean (SD) age of 34.5 (11.3) years and body mass index of 29.2 (1.4) kg m(-2) over 10 days using the DLW technique. All food and beverages were self-reported for 9-days using a web-based food record and mean daily EI calculated. Food record accuracy was assessed by calculating the absolute (EI - TEE) and percentage (EI/TEE × 100) differences between EI and TEE. Women were identified as under-reporters of EI based on the 95% confidence limits of the expected EI : TEE of 1. The mean (SD) self-reported EI was 8351 (1225) kJ day(-1) [1996 (293) kcal day(-1) ] and TEE was 10 648 (1774) kJ day(-1) [2545 (424) kcal day(-1) ]. The mean (SD) absolute difference in self-reported EI and TEE was -2301 (1535) kJ day(-1) [-550 (367) kcal day(-1) ], representing a mean reporting accuracy of 79.6% (14.1%), with four participants under-reporting EI. This pilot study highlights the opportunity for the use of the Internet as a novel medium for recording and assessing dietary intake. Although further research is needed in more diverse population groups, the accuracy of web-based food records for assessing EI appears to be consistent with other published dietary intake methods.

Comparison of methods to assess energy expenditure and physical activity in people with spinal cord injury

ObjectiveTo compare different methods of assessing energy expenditure (EE) and physical activity (PA) in people with spinal cord injury (SCI) under community-dwelling conditions.MethodsA reference standard encompassing the doubly labelled water (DLW) technique, heart rate monitoring (FLEX-HR), a multi-sensor armband (SenseWear Armband (SWA)), and two PA recall questionnaires were employed in 14 people with SCI to estimate EE and leisure-time PA.ResultsMean total daily energy expenditure (TDEE) assessed by DLW, FLEX-HR, and SWA were 9817 ± 2491 kJ/day, 8498 ± 1516 kJ/day, and 11414 ± 3242 kJ/day, respectively. Physical activity energy expenditure (PAEE) quantified by DLW was 2841 ± 1626 kJ/day, 2935 ± 1732 kJ/day estimated from FLEX-HR, and 2773 ± 2966 kJ/day derived from SWA. After converting the PA recall questionnaire data to EE in kJ/day, PAEE for the Physical Activity Recall Assessment for People with Spinal Cord Injury (PARA-SCI) was 2339 ± 1171 kJ/day and for Physical Activity Scale for Individuals with Physical Disabilities (PASIPD) 749 ± 1026 kJ/day. DLW-quantified PAEE was moderately associated with PARA-SCI (R2 = 0.62, P < 0.05), but not with the other estimates of PAEE (R2 ranged between 0.13 and 0.30, P > 0.05).ConclusionOur findings revealed that the PARA-SCI recall questionnaire was the best estimate of PAEE compared to the reference standard DLW approach. Although the between-method variability for SWA, FLEX-HR, and PASIPD-derived PAEE was small, there was a weak association between these methods and the criterion DLW technique. The best estimate of DLW-quantified TDEE was by FLEX-HR. SWA significantly overestimated TDEE in this population.

Validation of a pre-coded food record for infants and young children

To assess the validity of a 7-day pre-coded food record (PFR) method in 9-month-old infants against metabolizable energy intake (ME(DLW)) measured by doubly labeled water (DLW); additionally to compare PFR with a 7-day weighed food record (WFR) in 9-month-old infants and 36-month-old children. The study population consisted of 36 infants (age: 9.03±0.2 months) and 36 young children (age: 36.1±0.3 months) enrolled in a cross-over design of 7 consecutive days PFR vs 7 consecutive days WFR. Children were randomly assigned to one method during week 1, crossing over to the alternative method in week 2. Total energy expenditure (TEE) and ME(DLW) were obtained in the 9-month-old infants using the DLW technique for 7 days while recording with PFR. For the 9-month-old group, PFR showed a mean bias of +726 kJ/day, equivalent to 24%, (P<0.0001) compared with ME(DLW) (n=29). Using WFR as the reference in this group no between-method differences were found for energy, fat and carbohydrate. Energy intake in the 36-month-old children was 12% higher in the PFR vs WFR (P<0.0001), and protein plus total fat intake were overestimated with the PFR (P=0.008, P<0.0001, respectively). The study indicates that the PFR may be a valuable tool for measuring energy, energy-yielding nutrients and foods in groups of 9-month-olds infants and 36-month-olds young children.