Energy Requirements Of Adults Research Articles

Proximate Composition of Three Head Organs (Brain, Eyes, Tongue), Three Visceral Organs (Liver, Heart, Gizzard), Skin and Muscle of Muscovy Duck- hen

The proximate compositions of brain (A), eyes (B), tongue (E), liver (D), heart (F), gizzard (C), skin (H) and muscle (G) of Muscovy duck-hen were determined. The proximate composition values ranged as follows (values in g/100g on dry weight basis) ash (0.18 – 3.77 ± 1.40), moisture (0.50 – 4.78± 1.40), protein (3.24 – 79.9 ± 29.7), fat (0.23 – 5.60 ± 2.04), carbohydrate (6.19 – 95.8 ± 33.6), dry matter (95.22 – 99.5± 1.40) and organic matter (91.45 – 99.27± 2.63) with all the parameters being significantly different among the samples. Metabolizable energy contribution from protein, fat and carbohydrate in the samples ranged from (kJ/100g/kcal/100g): 740(180) – 7924(1864). Percentage energy contribution range was 5.53/5.70 – 59.2/59.1. Whereas the crude fat ranged from 0.23 – 5.60 g/100g, the total fatty acid (TFA) ranged from 0.217 – 5.08 g/100g or EPg/100g with corresponding energy of (kJ/100g versus kcal/100g): 8.51/2.07 – 207/50.4 and 8.03/1.95 – 188/45.7 respectively. UEDP% (assuming 60% energy utilization) range was 1.95/1.96 – 49.0/48.9. Approximate sample weight equivalents to the energy requirements of adults and infants had ranges of : for 2500kcal per day, sample range was 617 – 644g (adults) and at 3000kcal per day, requirement was 741 – 773g (adults); infant at 740kcal would require 183 – 191g. Water balance for protein metabolism had value range of 6.48 – 160ml. Correlational analyses of samples at r=0.01 gave these results: A/B (0.3024), B/E (0.1794), A/E (0.9916), C/D (0.9994), D/F (0.9892), C/F (0.9923) and G/H (-0.2014). Hence, Muscovy duck-hens are good sources of protein, metabolizable energy and low fat.

Validity of Two Questionnaires and Two Prediction Equations for Estimating Total Energy Expenditure in Healthy Adults: A Doubly Labeled Water Study

Abstract Objectives The doubly labeled water (DLW) method is the gold standard for assessing total energy expenditure (TEE), but is costly. Questionnaires and prediction equations for TEE are nearly cost-free but research on their validity is scarce. We evaluated the validity of TEE assessed by two questionnaires and two prediction equations in comparison with TEE assessed by DLW. Based on previous work, we hypothesized that the questionnaires would be valid at a group level, and that the prediction equations would be valid at an individual level. Methods Data from a 10-d observational study in 124 healthy, nonsmoking adults were used (63% F, aged 29.8 ± 12.2 y, BMI 24.5 ± 3.9 kg/m2 (Mean ± SD)). TEE was measured by DLW using a mixed oral 2H218O dose containing 0.15 g 2H218O and 0.07 g of 2H2O per kg body weight. Analysis of urine samples and calculations of TEE were carried out using standard methodology. TEE was estimated from the 7-day Physical Activity Recall (7dPAR; Sallis et al. 1985), the Block Work and Home Survey (BWHS; Block et al. 2009), Dietary Reference Intakes (DRI) equations for estimated energy requirements of adults with normal weight or overweight/obesity (IOM 2005), and the BOD POD air displacement plethysmograph. 7dPAR TEE was estimated by multiplying MET-min/day with resting metabolic rate estimated from DRI basal energy expenditure equations. The BOD POD measured body composition by densitometry and TEE was estimated from fat-free mass and fat mass (Nelson et al. 1992) and an activity factor (WHO 1985). Results TEE values were 2430 ± 535 (DLW), 2375 ± 445 (7dPAR), 2407 ± 750 (BWHS), 2335 ± 388 (DRI), 2134 ± 439 (BOD POD) kcal/d (Mean ± SD), with DRI and BOD POD significantly lower than DLW (P <0.01). Mean ± 2SD limits of agreement (kcal/d) between DLW and 7dPAR (−766, 877) and BWHS (−1420, 1468) were wider than those between DLW and DRI (−630, 822) and BOD POD (−463, 1057). The R2 and SEE of the method associations with DLW ranged from 0.17 to 0.54 and 264 to 688 kcal/d, respectively (all P = 0.000). Conclusions The 7dPAR and BWHS were valid for estimating TEE at a group level. While the DRI and BOD POD equations were more accurate at estimating TEE of individuals, none of the tools are recommended for individual assessment of TEE due to their low R2 and wide Bland-Altman limits of agreement with DLW. Funding Sources NIH R01 DK075862 and Purdue University.

Adult energy requirements predicted from doubly labeled water.

Estimating energy requirements forms an integral part of developing diet and activity interventions. Current estimates often rely on a product of physical activity level (PAL) and a resting metabolic rate (RMR) prediction. PAL estimates, however, typically depend on subjective self-reported activity or a clinician's best guess. Energy-requirement models that do not depend on an input of PAL may provide an attractive alternative. Total daily energy expenditure (TEE) measured by doubly labeled water (DLW) and a metabolic chamber from 119 subjects obtained from a database of pre-intervention measurements measured at Pennington Biomedical Research Center were used to develop a metabolic ward and free-living models that predict energy requirements. Graded models, including different combinations of input variables consisting of age, height, weight, waist circumference, body composition, and the resting metabolic rate were developed. The newly developed models were validated and compared to three independent databases. Sixty-four different linear and nonlinear regression models were developed. The adjusted R2 for models predicting free-living energy requirements ranged from 0.65 with covariates of age, height, and weight to 0.74 in models that included body composition and RMR. Independent validation R2 between actual and predicted TEE varied greatly across studies and between genders with higher coefficients of determination, lower bias, slopes closer to 1, and intercepts closer to zero, associated with inclusion of body composition and RMR covariates. The models were programmed into a user-friendly web-based app available at: http://www.pbrc.edu/research-and-faculty/calculators/energy-requirements/ (Video Demo for Reviewers at: https://www.youtube.com/watch?v=5UKjJeQdODQ ) CONCLUSIONS: Energy-requirement equations that do not require knowledge of activity levels and include all available input variables can provide more accurate baseline estimates. The models are clinically accessible through the web-based application.

Neandertal growth: What are the costs?

Energetic approaches have been increasingly used to address key issues in Neandertal palaeoecology and palaeobiology. Previous research has focused exclusively on the energy requirements of adults and highlights the high energy demands of these individuals compared with modern humans. Less attention has been paid to the energy requirements of sub-adult Neandertals, even though this age group could provide clues for a better understanding of Neandertal life history. Accordingly, herein, we estimate the energy costs of maintenance and growth in Neandertal infants and children from one to six years of age and compare these costs with values for modern humans. Statural growth models for two modern human populations (Beasain and Evenki) and an average Neandertal model population are used to establish weight growth models. In turn, these models of body weight growth are used to estimate key components of energetic variables (basal metabolic rate, total energy expenditure, energy of growth and daily energy requirements). Between three and six years of age, Neandertal children have slightly lower basal and growth energy costs than do modern humans of the same age, due primarily to their smaller body mass and slower growth rates. The reduction in energy allocated to growth is likely the result of metabolic adaptations to other somatic factors and thermal stress. Data from contemporary human infants and children suggest that even mild cold stress increases non-shivering thermogenesis, thus elevating metabolic needs by 50% or more. These results suggest that thermal stress likely played a strong role in shaping the delayed developmental patterns and lower energy allocated to growth during early life in Neandertals relative to Homo sapiens.

Adults in All Body Mass Index Categories Underestimate Daily Energy Requirements

To compare the difference between self-reported and calculated daily energy requirements ofadults within different body mass index (BMI) categories. Adults (n = 978) self-reported daily energy requirements, demographic information, and height, weight, age, and physical activity level (PAL) to calculate total energy expenditure. The main effects of BMI, gender, PAL, and dieting status on the difference between self-reported and calculated energy requirements for weight maintenance were significant (P < .05); age, race/ethnicity, level of education, and being in a health-related field had no effect. Individuals across all BMI categories underestimated their energy requirements, but obese individuals underestimated to the greatest degree. Males, current dieters, and those who reported a low-active or active PAL underestimated to the greatest extent in each category. There is a lack of basic nutrition knowledge about personal energy needs in individuals across all BMI categories regardless of age, race/ethnicity, level of education, or work/training in a health-related field.

Chapter 16. Glucose and nutrition

Chapter 16. Glucose and nutrition

Diet quality index adjusted for energy requirements in adults

This study aimed to develop a diet quality index (DQI-a) adjusted for energy requirement. Dietary intake of adults was assessed using 24-hour food recall. The DQI was developed for scores evenly distributed across ten items characterizing different aspects of diet: food groups, nutrients, and variety. The components categorized under the food groups from the Dietary Guide for Brazilians were adjusted according to the estimated energy requirements of the population studied. Index consistency and correlation with nutrients of the diet was analyzed by Cronbach's alpha. A total of 737 individuals were assessed and energy requirements ranged from 1,800 to 2,500kcal among women and 2,500 to 3,400kcal in men. The food group with greatest variation in total portions was cereals and tubers. Cronbach's alpha of the DQI-a was 0.643 and the index correlated with most of the nutrients. The DQI-a can be considered a valuable instrument for assessing diet quality of the Brazilian population.

Differences between brain mass and body weight scaling to height: potential mechanism of reduced mass-specific resting energy expenditure of taller adults

Adult resting energy expenditure (REE) scales as height( approximately 1.5), whereas body weight (BW) scales as height( approximately 2). Mass-specific REE (i.e., REE/BW) is thus lower in tall subjects compared with their shorter counterparts, the mechanism of which is unknown. We evaluated the hypothesis that high-metabolic-rate brain mass scales to height with a power significantly less than that of BW, a theory that if valid would provide a potential mechanism for height-related REE effects. The hypothesis was tested by measuring brain mass on a large (n = 372) postmortem sample of Thai men. Since brain mass-body size relations may be influenced by age, the hypothesis was secondarily explored in Thai men age < or =45 yr (n = 299) and with brain magnetic resonance imaging (MRI) studies in Korean men (n = 30) age > or =20<30 yr. The scaling of large body compartments was examined in a third group of Asian men living in New York (NY, n = 28) with MRI and dual-energy X-ray absorptiometry. Brain mass scaled to height with a power (mean +/- SEE; 0.46 +/- 0.13) significantly smaller (P < 0.001) than that of BW scaled to height (2.36 +/- 0.19) in the whole group of Thai men; brain mass/BW scaled negatively to height (-1.94 +/- 0.20, P < 0.001). Similar results were observed in younger Thai men, and results for brain mass/BW vs. height were directionally the same (P = 0.09) in Korean men. Skeletal muscle and bone scaled to height with powers similar to that of BW (i.e., approximately 2-3) in the NY Asian men. Models developed using REE estimates in Thai men suggest that brain accounts for most of the REE/BW height dependency. Tall and short men thus differ in relative brain mass, but the proportions of BW as large compartments appear independent of height, observations that provide a potential mechanistic basis for related differences in REE and that have implications for the study of adult energy requirements.

How much may I eat? Calorie estimates based upon energy expenditure prediction equations

How much may I eat? Most healthcare workers, when asked this question, have insufficient knowledge to educate their patients on a healthy energy intake level. In this review we examine the available methods for estimating adult energy requirements with a focus on the newly developed National Academy of Sciences/Institute of Medicine (NAS/IOM) doubly-labelled water total energy expenditure (TEE) prediction equations. An overview is first provided of the traditional factorial method of estimating energy requirements. We then extend this overview by exploring the development of the NAS/IOM TEE prediction models and their role in estimating energy requirements as a function of sex, age, weight, height and physical activity level. The NAS/IOM prediction models were developed for evaluating group energy requirements, although the formulas can be applied in individual 'example' patients for educational purposes. Potential limitations and interpretation issues of both the factorial and NAS/IOM methods are examined. This information should provide healthcare professionals with the tools and understanding to appropriately answer the question, 'How much may I eat?'

Environmental conditions and life history constraints determine foraging range in breeding Adélie penguins

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 310:247-261 (2006) - doi:10.3354/meps310247 Environmental conditions and life history constraints determine foraging range in breeding Adélie penguins Judy Clarke1,*, Louise M. Emmerson1, Petr Otahal2 1Department of the Environment and Heritage, Australian Antarctic Division, 203 Channel Hwy, Kingston, Tasmania 7050, Australia 235 Seventh Ave, West Moonah, Tasmania 7009, Australia *Email: judy.clarke@bigpond.com ABSTRACT: Foraging movements of Adélie penguins are constrained both by environmental conditions (e.g. sea ice cover) and life history factors (e.g. regular offspring provisioning). We describe within season changes in foraging range, trip duration and body condition of Adélie penguins nesting at Béchervaise Island, East Antarctica, in the context of these constraints. Penguins were satellite tracked over multiple seasons during the incubation, guard, crèche and pre-moult phases of their annual cycle. They ranged farthest during incubation when sea ice was extensive and shortest during the guard stage when chicks were small and sea ice limited in extent. Prior to their annual moult the birds foraged hundreds of kilometres to the west and east of their breeding sites. A recurrent polynya facilitated access to the sea early in the season when ice cover was extensive. Kernel analyses showed that penguins foraged most intensively close to the colony, along submarine canyons and at the continental shelf break. Increases in foraging range, as the chick rearing period progressed, were consistent with changing energy requirements of adults and chicks and likely intraspecific competition. Whilst provisioning their offspring, penguins adopted a variable combination of time minimising and food maximising foraging behaviour in which choice of foraging rule was determined largely by adult body condition. KEY WORDS: Satellite tracking · Pygoscelis adeliae · Foraging range · Chick provisioning · Body condition · Kernel analysis · Polynya Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 310. Online publication date: April 03, 2006 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2006 Inter-Research.

Energy requirements of adults

To describe issues related to energy requirements of free living adults and discuss the importance of basal metabolic rate (BMR) and their relationships to total energy expenditure (TEE ) and physical activity level (PAL, derived as TEE/BMR) and to determine the influence of body weight, height, age and sex. Based on a review of the literature, this paper examines the variability in BMR due to methodology, ethnicity, migration and adaptation (both metabolic and behavioural) due to changes in nutritional status. Collates and compiles data on measurements of TEE in free living healthy adults, to arrive at limits and to compare TEE of populations with different life-styles. The constancy of BMR and its validity as a reliable predictor of TEE in adults as well as the validity of PAL as an index of TEE adjusted for BMR and thus its use to categorise the physical activity pattern and lifestyle of an individual was confirmed. The limits of human daily energy expenditure at around 1.2 x BMR and 4.5 x BMR based on measurements made in free living adults have been reported in the literature. A large and robust database now exists of energy expenditure measurements obtained by the doubly labelled water method in the scientific literature and the data shows that, in general, levels of energy expenditure are similar to the recommendations for energy requirements adopted by FAO/WHO/UNU (1985). The review also confirms that metabolic adaptation to energy restriction is not an important factor that needs to be considered when recommending energy requirements for adults in developing countries.

P0088 PP* ENERGY REQUIREMENTS IN ACUTE PANCREATITIS IN CHILDREN

Introduction: The management of acute pancreatitis involves resting the pancreas to reduce secretion of pancreatic enzymes. Nutrition support is often provided as total parenteral nutrition and nil orally. The calorie requirements in children with this condition are undefined. However, it is thought that energy requirements in adults with acute pancreatitis are increased by 20% (1). Our aim was to define energy requirements in acute pancreatitis in children given total parenteral nutrition. Methods: We reviewed a series of 8 children with acute pancreatitis who were given total parenteral nutrition for over 1 week. We looked at the non-nitrogen energy provided in the parenteral nutrition needed to stabilize body weight. Energy provision met with Estimated Average Requirements (2) in the first instance. This was thought to be an acceptable starting point for parenteral nutrition, as the increased requirements in pyrexia and trauma are balanced by a lack of activity, a lack of energy required for digestion and absorption, and the lack of consideration for nitrogen calories provided (the anomaly in parenteral prescriptions). All in the series had careful fluid and electrolyte balance studies to ensure any weight deviation was not related to hydration status. All in the series had periodic mild to moderate pyrexia, which responded to antibiotics. Results: The aetiology in these children were: trauma (n=4); pancreatic divisum (n=1); gallstones (n=1); and idiopathic (n=2). All aged between 8–13 years. The mean duration of parenteral nutrition required was 19 days (range 7–40 days). Most in our series (n=6) initially lost weight (range 1–3kg), the rest remained stable (n=2). An increase in energy provision was required of 110% (n=4) and 120% (n=2) Estimated Average Requirement to prevent further weight loss. Conclusion: Energy requirements in this small group were clearly on average above the Estimated Average Requirement. In future prescriptions of parenteral nutrition in acute pancreatitis in children, we will use 110% Estimated Average Requirement for initiation of non-nitrogen energy provision. In severe sepsis 120% Estimated Average Requirement would be fortuitous.

Estimation of energy requirements for adults: Tehran lipid and glucose study.

This study was conducted to determine the energy intake of adult residents of district 13 of Tehran and compare the results with their energy requirements. In this cross-sectional study, 403 subjects were selected by random sampling, including 145 men and 151 women aged 25-50 years and 57 men and 50 women over 50 years old in the framework of Tehran Lipid and Glucose Study (TLGS). Height, body weight, waist and hip circumferences were measured, and the body mass index (BMI) and waist-to-hip ratio (WHR) were calculated. Mean energy requirements for each sex-age group were estimated by multiplying specific coefficients (allocated to each group) by body weight and resting energy expenditure (REE), and the results of both methods were compared with mean energy values recommended by Food and Agriculture Organization (FAO)/World Health Organization (WHO) and the U.S. recommended dietary allowance (RDA). Dietary assessment was performed by 48-hour diet recall. A ratio of energy intake to basal metabolic rate lower than 1.27 was considered as under-reporting. Physical activity was evaluated by standard questionnaire of the Lipid Research Clinics (LRC). Women were significantly more overweight and obese than men (p < 0.001) and older women were more obese than younger ones (p < 0.05). Only one-third of the study population had adequate physical activity. Women had significantly lower physical activity than men (p < 0.01). Energy requirements for both age and sex groups were lower than recommended daily allowances for energy: men 25-50; 2576 vs. 2900; men > 50: 2155 vs. 2300; women 20-50: 2045 vs. 2200 and women > 50: 1817 vs. 1900 kilocalories (kcal). Reported energy intake of men was higher and that of women was lower than the RDA. Forty percent of women and 14% of men under-reported their energy intake. The energy requirement of the average Tehranian is lower than daily allowances; conditions of obesity and overweight are more prevalent in women. There is high frequency of under-reporting of energy intake in women. Lifestyle modifications to improve dietary habits and to increase physical activity are recommended to decrease overweight and obesity in urban population of Tehran.

Changes in body condition in breeding kittiwakes Rissa tridactyla

We investigated the seasonal pattern of changes in body condition of breeding black‐legged kittiwakes Rissa tridactyla in Svalbard (79°N) to evaluate whether changes in body condition were a consequence of the energetic demands of breeding (the reproductive stress hypothesis) or of voluntary anorexia to attain lower flight costs during chick rearing (the programmed anorexia hypothesis). Adult body condition was recorded from early egg laying to fledging and was examined in relation to date (relative to hatching), sex, parental time‐budget, brood size and reproductive success. To distinguish between the two hypotheses we evaluate whether the reduction in body condition occurred during or ahead of the energetically most demanding part of the chick‐rearing period. We combine our results on changes in body condition and time‐budget with published information on field metabolic rate (FMR) and chick energy requirements from studies in the same colony. Our calculations of adult energy requirements and energy intakes indicate that the first part of the chick‐rearing period was energetically the most demanding period, because adult energy requirement per hour spent off the nest was highest in this period, and adults were time constrained because of the need for 24‐h brooding of the chicks. During the incubation period female body condition increased slightly, but significantly, while male body condition was stable. During the first part of the chick‐rearing period, female and male body condition decreased by 14.8% and 8.4%, respectively. During the second part of the chick‐rearing period, both male and female body condition remained stable. The reductions in body condition occurred during the phase which was suggested to be the energetically most demanding part of the chick‐rearing period, thus supporting the reproductive stress hypothesis. Parental body condition during the incubation period was positively related to the probability of successfully fledging young, providing additional support for the reproductive stress hypothesis.

Equations for predicting the energy requirements of healthy adults aged 18–81 y

Recent studies have questioned the accuracy of using the current recommended dietary allowances (RDAs) to predict usual energy requirements in adults. We developed equations to predict adult energy requirements from simple anthropometric and laboratory measures by using the doubly labeled water method to determine each subject's total energy expenditure (TEE), which is equal to usual energy requirements in weight-stable individuals. This was a cross-sectional study conducted with 93 healthy, free-living adults [44 men and 49 women; body mass index range (in kg/m2): 18.4-31.8] aged 18-81 y. Body fat and fat-free mass were measured by underwater weighing, physical activity was estimated by using activity monitors, and resting energy expenditure was determined by indirect calorimetry. Information on anthropometric variables and reported strenuous activity was also collected. Three regression equations were developed and verified for accuracy by using bootstrap analysis and doubly labeled water data published by other research groups. The first equation used information on only age, weight, height, and sex and had an SEE for prediction of TEE of 1.80 MJ/d. The second and third equations used different combinations of basic and laboratory data and had SEEs of 1.55 and 1.65 MJ/d, respectively. With use of the same analytic approaches, the RDAs for energy were shown to significantly underestimate usual energy needs by approximately 10%; the extent of underestimation was significantly greater for subjects with high TEEs than for subjects with low TEEs. Regression equations based on doubly labeled water measurements of TEE appear to be more accurate than the current RDAs for predicting energy requirements in healthy, nonobese adults living in affluent countries.

Ontogeny of Differential Migration and Sexual Segregation in Northern Elephant Seals

Adult northern elephant seals ( Mirounga angustirostris ) are substantially sexually dimorphic in size and in migratory behavior. Both sexes migrate over vast areas of the North Pacific Ocean during biannual migrations between rookeries in California waters and northern foraging grounds, but adult males segregate from adult females during each of these double migrations. I used satellite-linked radiotelemetry to document the ontogeny of differential migration and sexual segregation as a means to better define the ultimate causal mechanisms of these patterns and to evaluate the potential influence of this sexually dimorphic trait on the magnitude of size dimorphism between sexes in the northern elephant seal. The initial direction of migration (northwesterly from rookeries) was established during the 1st year of life in both males and females. Differential migration and sexual segregation appears to develop during puberty, when growth rates of males are substantially greater than those of females, and those patterns are well established by the time males are 4.5–5 years old. This outcome suggests that the development and proximate cause of sexual segregation of northern elephant seals is more precisely related to differential metabolic needs of males during the period of sexual maturation and accelerated growth rather than to sexual differences in gross energy requirements of adults. Segregation appears to confer to pubescent males survival benefits, which more than compensate for the higher mortality that generally is associated with rapid growth during puberty in other taxa with male-biased, sexual dimorphism. The most parsimonious explanation for the evolution of sexual dimorphism in size in northern elephant seals still appears to be sexual selection (intrasexual competition) acting through differential mating success of males. Moreover, differential, rapid growth during puberty and deferred maturity of males versus females are proximate mechanisms promoting larger size of males as adults. I suggest, however, that natural selection has led to sexually dimorphic migratory patterns and segregation of foraging elephant seals and that the segregation may partially maintain and, indeed, enhance sexual dimorphism in size.

Total Energy Expenditure in Adults with Cerebral Palsy as Assessed by Doubly Labeled Water

Objectives To characterize total energy expenditure (TEE) in free-living adults with cerebral palsy (CP) using the doubly labeled water technique, and to determine those physiologic variables and characteristics of CP that were markers of TEE in adults with CP. Design TEE was measured using the doubly labeled water technique in 30 free-living adults with CP (12 women, 18 men). To determine the best markers of TEE, the following factors were examined: CP status, resting metabolic rate (RMR), anthropomet-ric characteristics and body composition by means of dual-energy x-ray absorptiometry (DXA) and skinfold thickness measurements, energy cost of leisure-time activities, and oral-motor impairment. Statistical analysis Means±standard deviations, t tests, Pearson product-moment correlation coefficients, Spearman rank correlation coefficients, χ 2, stepwise multiple-correlation regression analysis, and analysis of covariance were used to examine the relationships among variables of interest. Results TEE was highly variable in the sample (mean=2,455±622 kcal/day for men and 1,986±363 kcal/day for women). Stepwise regression analysis showed that TEE was best predicted in the sample by RMR, percentage body fat determined by DXA, ambulation status, and sex (multiple R=.68, P=.003). When practical, easily measured variables were used, TEE was best predicted by height, ambulation status, percentage body fat by skinfold thickness measurements, and sex (multiple R=.61, P.=018). The contribution of energy expended in physical activity to TEE was significantly higher in the ambulatory subjects than the nonambulatory subjects (25% vs 16%, respectively; P=.009). Applications The high degree of variability in TEE, largely attributable to high interindividual variation in energy expended in physical activity, makes it difficult to provide general guidelines for energy requirements for adults with CP. Because ambulation status was an important predictor of TEE, it must be accounted for in estimating energy requirements in this population.

Athetosis Increases Resting Metabolic Rate in Adults with Cerebral Palsy

Objectives To determine whether resting metabolic rate (RMR) is higher or lower in adults with cerebral palsy compared with the RMR of control subjects and to further examine physical characteristics of cerebral palsy that might affect RMR. Design Twenty-one adults with cerebral palsy (9 women, 12 men) were compared with 50 control subjects (25 men, 25 women) within the same age range (18 through 50 years). The following measurements were made: RMR by indirect calorimetry, anthropometries, body composition, and habitual physical activity patterns. The study was conducted at the University of Vermont General Clinical Research Center and the Ball State University Human Performance Laboratory. Statistical analyses Mean values±standard deviations, t tests, Pearson product-moment correlation coefficients, analysis of covariance, and stepwise multiple correlation regression analysis were used to examine the relationships among variables of interest. Results No significant differences were found in body weight, body mass index, fat mass, percentage body fat, and measured RMR between the two groups. The subjects with cerebral palsy were significantly shorter, had less fat-free mass, and expended fewer kilocalories in leisure time activities than the control subjects. After statistical adjustment for differences in fat-free mass, the subjects with cerebral palsy had a 14% ( P<.001) higher adjusted RMR (1,742 kcal/day) compared with that of the control subjects (1,534 kcal/day). According to stepwise regression analysis, RMR was best predicted in the entire sample by fat-free mass and the presence or absence of athetosis (multiple R=.83, P<.001). The presence of cerebral palsy alone was not significantly correlated with RMR. Conclusions The increased energy requirements of adults with cerebral palsy can be partially explained by athetotic movements. In this sample, the presence of athetosis increased RMR by an average of 524 kcal/day. JAm Diet Assoc. 1995; 95:145-148.

Host‐feeding and oviposition by parasitoids in relation to host stage: Consequences for parasitoid‐host population dynamics

SummaryAmong parasitoids which host‐feed destructively, there is a tendency for females to partition their feeding and oviposition behaviour in relation to different host stages, feeding preferentially or exclusively on earlier host stages and ovipositing preferentially or exclusively in (or on) later ones. We explored the dynamic implications of this behaviour for parasitoid‐host population dynamics, using modifications of the age‐structured simulation models of Kidd and Jervis (1989, 1991).Using the new versions of the models, we compared the situation where parasitoids practice host stage discrimination with respect to feeding and oviposition, with the situation where they do not. Additionally, we examined the effects of host stage discrimination on populations by (a) having generations either discrete or overlapping, (b) varying initial age structure, (c) having varying degrees of density dependence acting on host adult mortality, and (d) varying parasitoid develoment times in relation to the length of host development.With either discrete or overlapping generations of the host population, a reduction in the parasitoid development time had a destabilizing influence on the parasitoid‐host population interaction. With discrete generations stage discrimination had no effect on the risk of extinction, irrespective of either the degree of density dependence acting on the host population, or the initial age structure of the host population. When parasitoid search was uncoupled from the insect's adult energy requirements, the interaction was always unstable. With continuous generations, stage discrimination affected stability at certain parasitoid development times, but not at others. The relative lengths of parasitoid and host development times also influenced the tendency of the host population to show discrete or overlapping generations.

Metabolism and nutritional adaptation to altered intakes of energy substrates

Adaptive changes in energy expenditure to changes in energy intake are far less than previously believed once changes in body weight and physical activity are taken into account. Alterations in metabolic efficiency of +/- 10% in total energy expenditure are the limits of what can normally be expected on prolonged under- or overfeeding. The supposed twofold variation in energy requirements of adults is based on measurements of food intake, which, despite involving weighted intakes over a week, cannot be considered realistic. Subtle differences in the energetic responses to fat, protein, and carbohydrate signify the different effective energetic contribution of isoenergetic substrates and may account for the propensity to obesity in individuals and societies on a high-fat diet.