Changes In Energy Expenditure Research Articles

Energy Metabolic Adaptation and Cardiometabolic Improvements One Year After Gastric Bypass, Sleeve Gastrectomy, and Gastric Band.

It is not known whether the magnitude of metabolic adaptation, a greater than expected drop in energy expenditure, depends on the type of bariatric surgery and is associated with cardiometabolic improvements. To compare changes in energy expenditure (metabolic chamber) and circulating cardiometabolic markers 8 weeks and 1 year after Roux-en-y bypass (RYGB), sleeve gastrectomy (SG), laparoscopic adjustable gastric band (LAGB), or a low-calorie diet (LCD). Design, Setting, Participants, and Intervention: This was a parallel-arm, prospective observational study of 30 individuals (27 females; mean age, 46 ± 2 years; body mass index, 47.2 ± 1.5 kg/m2) either self-selecting bariatric surgery (five RYGB, nine SG, seven LAGB) or on a LCD (n = 9) intervention (800 kcal/d for 8 weeks, followed by weight maintenance). After 1 year, the RYGB and SG groups had similar degrees of body weight loss (33-36%), whereas the LAGB and LCD groups had 16 and 4% weight loss, respectively. After adjusting for changes in body composition, 24-hour energy expenditure was significantly decreased in all treatment groups at 8 weeks (-254 to -82 kcal/d), a drop that only persisted in RYGB (-124 ± 42 kcal/d; P = .002) and SG (-155 ± 118 kcal/d; P = .02) groups at 1 year. The degree of metabolic adaptation (24-hour and sleeping energy expenditure) was not significantly different between the treatment groups at either time-point. Plasma high-density lipoprotein and total and high molecular weight adiponectin were increased, and triglycerides and high-sensitivity C-reactive protein levels were reduced 1 year after RYGB or SG. Metabolic adaptation of approximately 150 kcal/d occurs after RYGB and SG surgery. Future studies are required to examine whether these effects remain beyond 1 year.

Allometric scaling of the elevation of maternal energy intake during lactation.

BackgroundIn most mammals, lactating mothers dramatically increase their food intake after parturition and reach a peak intake rate after a certain time while their offspring continue to grow. A common view, perpetuated by the metabolic theory of ecology, is that the allometric scaling of maternal metabolic rate with body mass limits the changes in energy intake and expenditure. Therefore these potential effects of metabolic scaling should be reflected in the elevation of maternal energy intake during lactation. To test this hypothesis, we collected published data on 24 species (13 domesticated) and established scaling relationships for several characteristics of the patterns of energy intake elevation (amplitude of the elevation, time to peak, and cumulative elevation to peak).ResultsA curvilinear allometric scaling relationship with maternal body mass (in double-logarithmic space) was found for the amplitude of maternal energy intake elevation, similarly to what has been observed for scaling relationships of basal metabolic rate in non-breeding mammals. This result indirectly supports the metabolic theory of ecology. However, this curvilinear allometric scaling does not seem to drive the scaling relationships found for the other characteristics of maternal energy intake. Both the duration and shape of the energy intake patterns showed substantial variation independently of species’ body mass.ConclusionsData available for a few mammals, mostly domesticated, provides little evidence for the hypothesis that a single law of metabolic scaling governs the elevation of maternal energy intake after parturition. Obtaining further food intake data in wild species will be crucial to unravel the general mechanisms underlying variation in this unique adaptation of mammalian females.Electronic supplementary materialThe online version of this article (doi:10.1186/s12983-016-0164-y) contains supplementary material, which is available to authorized users.

Loss of Mrap2 is associated with Sim1 deficiency and increased circulating cholesterol.

Melanocortin receptor accessory protein 2 (MRAP2) is a transmembrane accessory protein predominantly expressed in the brain. Both global and brain-specific deletion of Mrap2 in mice results in severe obesity. Loss-of-function MRAP2 mutations have also been associated with obesity in humans. Although MRAP2 has been shown to interact with MC4R, a G protein-coupled receptor with an established role in energy homeostasis, appetite regulation and lipid metabolism, the mechanisms through which loss of MRAP2 causes obesity remains uncertain. In this study, we used two independently derived lines of Mrap2 deficient mice (Mrap2tm1a/tm1a) to further study the role of Mrap2 in the regulation of energy balance and peripheral lipid metabolism. Mrap2tm1a/tm1a mice have a significant increase in body weight, with increased fat and lean mass, but without detectable changes in food intake or energy expenditure. Transcriptomic analysis showed significantly decreased expression of Sim1, Trh, Oxt and Crh within the hypothalamic paraventricular nucleus of Mrap2tm1a/tm1a mice. Circulating levels of both high-density lipoprotein and low-density lipoprotein were significantly increased in Mrap2 deficient mice. Taken together, these data corroborate the role of MRAP2 in metabolic regulation and indicate that, at least in part, this may be due to defective central melanocortin signalling.

Energy Intake and Energy Expenditure for Determining Excess Weight Gain in Pregnant Women.

To conduct a secondary analysis designed to test whether gestational weight gain is the result of increased energy intake or adaptive changes in energy expenditures. In this secondary analysis, energy intake and energy expenditure of 45 pregnant women (body mass index [BMI] 18.5-24.9 [n=33] and BMI 25 or greater [n=12]) were measured preconceptionally and at 22 and 36 weeks of gestation. Energy intake was calculated as the sum of total energy expenditure measured by doubly-labeled water and energy deposition determined by the four-compartment body composition model. Measurements of weight, body composition, and basal metabolic rate were completed preconceptionally and 9, 22, and 36 weeks of gestation. Basal metabolic rate was measured by indirect calorimetry in a room calorimeter and activity energy expenditure by doubly-labeled water. Energy intake from 22 to 36 weeks of gestation was significantly higher in high gainers (n=19) (3,437±99 kcal per day) compared with low+ideal gainers (n=26) (2,687±110, P<.001) within both BMI categories. Basal metabolic rate increased in proportion to gestational weight gain; however, basal metabolic rate adjusted for body composition changes with gestational weight gain was not significantly different between high gainers and low+ideal gainers (151±33 compared with 129±36 kcal per day; P=.66). Activity energy expenditure decreased throughout pregnancy in both groups (low+ideal gainers: -150±70 kcal per day; P=.04 and high gainers: -230±92 kcal per day; P=.01), but there was no difference between high gainers and low+ideal gainers (P=.49). Interventions designed to increase adherence to the Institute of Medicine guidelines for weight gain in pregnancy may have increased efficacy if focused on limiting energy intake while increasing nutrient density and maintaining levels of physical activity.

Obesogen effects after perinatal exposure of 4,4'-sulfonyldiphenol (Bisphenol S) in C57BL/6 mice.

Bisphenol A were removed from consumer products and replaced by chemical substitutes such as Bisphenol S (BPS). Based on their structural similarity, BPS may be obesogen like Bisphenol A in mice. Our objective was to determine the impact of BPS on lipid homeostasis in C57Bl/6 mice after perinatal and chronic exposure. Pregnant mice were exposed to BPS via the drinking water (0.2; 1.5; 50μg/kg bw/d). Treatment began at gestational day 0 and continued in offspring up to 23-weeks old. Then, offspring mice were fed with a standard or high fat diet. The body weight, food consumption, fat mass and energy expenditure were measured. A lipid load test was performed to check the postprandial triglyceridemia. Plasma parameters and mRNA gene expression in adipose tissues were also analysed. BPS induced overweight in male mice offspring fed with a HFD at the two highest doses. There was no change in food intake and energy expenditure. The overweight was correlated to the fat mass, hyperinsulinemia and hyperleptinemia. The plasma triglyceride clearance was significantly increased with BPS and tyloxapol(®) (triglyceride clearance inhibitor) reversed this phenomenon. BPS induced alteration in mRNA expression of marker genes involved in adipose tissue homeostasis: hormone sensitive lipase, PPARγ, insulin receptor, SOCS3 and adiponectin. This is the first time that BPS is described as obesogenic at low doses and after perinatal and chronic exposure in male mice. BPS potentiated the obesity induced by a HFD by inducing the lipid storage linked to faster lipid plasma clearance.

Integrin‐Linked Kinase Enhances Skeletal Muscle Fatty Acid Metabolism In Vivo

Accumulation of extracellular matrix (ECM) components and activation of specific integrin receptors contribute to skeletal muscle (SkM) insulin resistance in the high fat (HF)‐fed mouse. Integrin‐linked kinase (ILK) is an adaptor protein that serves as a hub for the integrin signaling but its role in metabolism is poorly defined. A shift from glucose to fatty acid (FA) oxidation is a hallmark of insulin resistance and diabetes, but the mechanisms responsible for this shift in nutrient utilization are unclear. Integrins have been implicated in the transcriptional regulation of mitochondrial biogenesis and are known to interact with FA transporters at the plasma membrane. The objective of this study was to test the novel hypothesis that integrins, through ILK signaling, enhance SkM FA metabolism under insulin resistant conditions.SkM‐specific ILK knockout mice (mILK‐KO) were generated using mice expressing Cre recombinase on the human SkM actin (HSA) promoter. Body weight was measured weekly and body composition was measured immediately prior to and following energy balance studies. mILK‐KO and their wild type (WT) littermates were fed a chow or HF diet (60% calories from fat) for 27 weeks then placed in metabolic cages for five days (n=6–9/group). Tissues were collected after a 5‐h fast. Pyruvate and FA‐supported mitochondrial respiratory capacity was measured in permeabilized SkM myofibers (PmFBs) from the soleus and EDL. Muscle free fatty acids (FFAs) and triglycerides (TGs) were measured in gastrocnemius with gas chromatography. Comparisons were made using Student's t‐test or 2‐way ANOVA as appropriate.HF‐fed mILK‐KO mice had a decreased reliance on FA oxidation compared to their WT littermates, as suggested by the increase in RQ. This RQ difference was independent of changes in whole body energy expenditure, body composition, food consumption or spontaneous activity. RQ was unchanged in mILK‐KO mice fed a chow diet. FA‐supported PmFB respiration was decreased in EDL, but not soleus, of HF‐fed mILK‐KO mice. Respiration in chow‐fed mice was not affected by muscle ILK deletion. Total muscle FFAs and TGs were increased by HF feeding but lower in mILK‐KO mice fed a HF diet. Muscle lipids were unaffected by ILK deletion in mice on a chow diet.These data are the first to demonstrate a mechanistic role for integrin signaling in the regulation of SkM FA metabolism in vivo and suggest that integrin signaling, through ILK, responds to nutrient overload by enhancing the uptake, storage and oxidation of FAs in SkM. These findings provide strong support for a model where extracellular cues (e.g. ECM expansion) cause a coordinated shift in cellular energetics, a paradigm that may permit for therapeutic targeting of oxidative metabolism through integrin receptors.Support or Funding InformationFunding for this project was provided by the following NIH grants: R01 DK054902, U24 DK059637, P30 DK020593, and T32 DK007061.

Evaluating a small change approach to preventing long term weight gain in overweight and obese adults — Study rationale, design, and methods

Despite the rapid rise in obesity worldwide, few strategies have been effective in treating this epidemic. An emerging strategy is to focus on preventing excessive weight gain rather than weight reduction. The proposed intervention, small change approach (SCA), is an innovative weight gain prevention strategy in which individuals monitor their usual nutrition and physical activity patterns and then make modest but sustainable alterations through behavioral intervention techniques (self-regulation, goal setting) enough to reduce overall energy balance by 100 to 200kcal per day (e.g., reduce caloric intake by 100kcal per day and/or increase daily step count by ~2000 steps (~100kcal) per day). The primary aim of the trial is to determine whether small changes in energy expenditure and/or energy intake prevent weight gain in overweight and obese men and women long-term. The pre-specified primary and secondary assessments are at 2 and 3years post-randomization respectively. The primary outcome is change in body weight. Secondary outcomes include body composition variables (adipose tissue distribution and lean mass distribution) and cardiorespiratory fitness (VO2peak).We randomized 320 primarily White (n=305) overweight and obese men and women to one of 2 conditions: 1) usual care (UC), 2) small change approach (SCA). Participant involvement in the study is 3years; 2year intervention with a 1year follow-up. Our study findings will indicate whether there is value in clinicians adopting a SCA to lifestyle counseling for their patients who are overweight and obese.

Diet-induced thermogenesis in postoperatve Roux-en-Y gastric bypass patients with weight regain

BackgroundBariatric surgery has been shown to be an effective treatment for obesity. Changes in energy expenditure, especially through diet-induced thermogenesis (DIT), have been identified as one of the mechanisms to explain this success. However, not all patients are able to maintain healthy postoperative weight loss. Therefore, a question arises: In the weight regain after bariatric surgery, are these changes in energy metabolism still active? ObjectiveTo investigate if weight regain after Roux-en-Y gastric bypass (RYGB) surgery is associated with a lower diet-induced thermogenesis in the late postoperative period. SettingA cross-sectional study with the participants chosen from among the patients from a private practice. MethodsThis was a cross-sectional study where 3 groups of female patients were evaluated: (1) 20 patients with a RYGB postoperative time period of at least 2 years, who kept a healthy weight after surgery (loss of at least 50% of excess weight; Healthy group); (2) 19 patients with clinically severe obesity (BMI>40 kg/m2, without co-morbidities and>35 kg/m2, with co-morbidities; Pre group); (3) 18 patients who experienced weight regain after RYGB (Regain group). The 3 groups were submitted to indirect calorimetry to measure resting metabolic rate (RMR), respiratory quotient (RQ), and DIT. Immediately after the RMR measurement, a mixed meal of regular consistency was offered. Ten minutes after the food intake began, energy expenditure measurements were initiated continuing throughout the following 3 postprandial hours. Body composition was evaluated using multifrequency bioelectrical impedance. In subgroups of the studied population, glucose and insulin levels were measured at baseline and at 30, 60, 90, 120, and 180 minutes after feeding. The mean area under the curve (AUC) between the 3 groups and measurements at baseline were compared using the analysis of variance (ANOVA). ResultsThe Healthy group had the highest weight adjusted RMR value compared with both the Pre and Regain group (23.03±3.02 kcal/kg; 16.18±2.94 kcal/kg; 17.11±3.28 kcal/kg, respectively; P<.0001). The Regain and Pre groups showed no difference for this variable. The weight-adjusted DIT (AUC 0–180 min) was about 42% and 34% higher in the Healthy group compared with the Pre and Regain groups, respectively (P<.0001). Lean body mass (kg) showed a positive correlation with the AUC of weight-adjusted DIT in the 3 groups. Multiple regression revealed that lean body mass was the only variable related to weight adjusted DIT, independent of group and other selected variables. ConclusionWeight-adjusted DIT in the Regain group was smaller compared with the Healthy group, and with no difference compared with the Pre group. The lean body mass seems to have a positive association with diet-induced thermogenesis.

Energy metabolism and nutritional status in hospitalized patients with lung cancer.

This study aimed to investigate the energy metabolism of patients with lung cancer and the relationship between energy metabolism and proinflammatory cytokines. Twenty-eight patients with lung cancer and 18 healthy controls were enrolled in this study. The nutritional status upon admission was analyzed using nutritional screening tools and laboratory tests. The resting energy expenditure and respiratory quotient were measured using indirect calorimetry, and the predicted resting energy expenditure was calculated using the Harris–Benedict equation. Energy expenditure was increased in patients with advanced stage disease, and there were positive correlations between measured resting energy expenditure/body weight and interleukin-6 levels and between measured resting energy expenditure/predicted resting energy expenditure and interleukin-6 levels. There were significant relationships between body mass index and plasma leptin or acylated ghrelin levels. However, the level of appetite controlling hormones did not affect dietary intake. There was a negative correlation between plasma interleukin-6 levels and dietary intake, suggesting that interleukin-6 plays a role in reducing dietary intake. These results indicate that energy expenditure changes significantly with lung cancer stage and that plasma interleukin-6 levels affect energy metabolism and dietary intake. Thus, nutritional management that considers the changes in energy metabolism is important in patients with lung cancer.

Effects of Exergaming on Physical Activity in Overweight Individuals

The majority of patients with overweight and type 2 diabetes show insufficient levels of daily physical activity (PA) and usually are among the least likely to engage in or adhere to any form of generic PA. Active video games (exergames) may be a solution to motivate these individuals to overcome their sedentary lifestyle. This systematic review was conducted to review the current evidence for the effectiveness of exergaming in overweight and type 2 diabetes mellitus and thus to evaluate the suitability of these games to be used as tools for exercise promotion that meet current PA guidelines. We searched electronic bibliographic databases (PubMed, Embase, Web of Science, OpenGrey, and the Cochrane Central Register of Controlled Trials) up to March 2015. Randomized controlled trials (RCT) and cross-sectional studies published in English in a peer-reviewed journal and analyzing the effects of exergames on objectively measured intensity parameters of PA in overweight (body mass index [BMI] ≥25kg/m(2)) adults (mean age ≥18years) with and without type 2 diabetes were included. Study selection, data extraction, and quality assessment were performed independently by two review authors. Primary outcomes included changes in oxygen uptake (VO2), energy expenditure (EE), heart rate (HR), or activity counts. Secondary outcomes were enjoyment of treatment, exercise adherence, ratings of perceived exertion (RPE), changes in body composition, and changes in blood parameters (serum glucose, long-term blood glucose, blood cholesterol, triglycerides, or serum lactate). Of 2845 records, 14 publications (11 studies) met the inclusion criteria. All included studies (ten experimental, cross-sectional laboratory studies and one RCT) were able to show increases in either VO2, EE, HR, or activity counts. However, effects of exergaming in terms of changes in these intensity parameters varied significantly between game modes and consoles as well as because of the vastly differing durations of exergame activity between studies. One of the included studies had a low risk of bias, and three had a high risk of bias; seven studies had an unclear risk of bias as the study description was insufficient. No studies were found investigating the changes in objectively measured PA intensity parameters in patients with type 2 diabetes. This review suggests that exergames are able to increase PA among overweight individuals. However, the inconsistent results and the overall poor or moderate methodological quality do not permit judgment on whether exergames are suitable to meet PA guidelines in this target group. The lack of research regarding the effects of exergames in type 2 diabetes indicates a great need for future research.

Metabolic phenotype and adipose and liver features in a high-fat Western diet-induced mouse model of obesity-linked NAFLD.

nonalcoholic fatty liver disease (NAFLD), an obesity and insulin resistance associated clinical condition - ranges from simple steatosis to nonalcoholic steatohepatitis. To model the human condition, a high-fat Western diet that includes liquid sugar consumption has been used in mice. Even though liver pathophysiology has been well characterized in the model, little is known about the metabolic phenotype (e.g., energy expenditure, activity, or food intake). Furthermore, whether the consumption of liquid sugar exacerbates the development of glucose intolerance, insulin resistance, and adipose tissue dysfunction in the model is currently in question. In our study, a high-fat Western diet (HFWD) with liquid sugar [fructose and sucrose (F/S)] induced acute hyperphagia above that observed in HFWD-fed mice, yet without changes in energy expenditure. Liquid sugar (F/S) exacerbated HFWD-induced glucose intolerance and insulin resistance and impaired the storage capacity of epididymal white adipose tissue (eWAT). Hepatic TG, plasma alanine aminotransferase, and normalized liver weight were significantly increased only in HFWD+F/S-fed mice. HFWD+F/S also resulted in increased hepatic fibrosis and elevated collagen 1a2, collagen 3a1, and TGFβ gene expression. Furthermore, HWFD+F/S-fed mice developed more profound eWAT inflammation characterized by adipocyte hypertrophy, macrophage infiltration, a dramatic increase in crown-like structures, and upregulated proinflammatory gene expression. An early hypoxia response in the eWAT led to reduced vascularization and increased fibrosis gene expression in the HFWD+F/S-fed mice. Our results demonstrate that sugary water consumption induces acute hyperphagia, limits adipose tissue expansion, and exacerbates glucose intolerance and insulin resistance, which are associated with NAFLD progression.

Minimal impact of age and housing temperature on the metabolic phenotype of Acc2-/- mice.

An important regulator of fatty acid oxidation (FAO) is the allosteric inhibition of CPT-1 by malonyl-CoA produced by the enzyme acetyl-CoA carboxylase 2 (ACC2). Initial studies suggested that deletion of Acc2 (Acacb) increased fat oxidation and reduced adipose tissue mass but in an independently generated strain of Acc2 knockout mice we observed increased whole-body and skeletal muscle FAO and a compensatory increase in muscle glycogen stores without changes in glucose tolerance, energy expenditure or fat mass in young mice (12-16 weeks). The aim of the present study was to determine whether there was any effect of age or housing at thermoneutrality (29 °C; which reduces total energy expenditure) on the phenotype of Acc2 knockout mice. At 42-54 weeks of age, male WT and Acc2(-/-) mice had similar body weight, fat mass, muscle triglyceride content and glucose tolerance. Consistent with younger Acc2(-/-) mice, aged Acc2(-/-) mice showed increased whole-body FAO (24 h average respiratory exchange ratio=0.95±0.02 and 0.92±0.02 for WT and Acc2(-/-) mice respectively, P<0.05) and skeletal muscle glycogen content (+60%, P<0.05) without any detectable change in whole-body energy expenditure. Hyperinsulinaemic-euglycaemic clamp studies revealed no difference in insulin action between groups with similar glucose infusion rates and tissue glucose uptake. Housing Acc2(-/-) mice at 29 °C did not alter body composition, glucose tolerance or the effects of fat feeding compared with WT mice. These results confirm that manipulation of Acc2 may alter FAO in mice, but this has little impact on body composition or insulin action.

Thyroid hormone and vitamin D regulate VGF expression and promoter activity.

The Siberian hamster (Phodopus sungorus) survives winter by decreasing food intake and catabolizing abdominal fat reserves, resulting in a sustained, profound loss of body weight. Hypothalamic tanycytes are pivotal for this process. In these cells, short-winter photoperiods upregulate deiodinase 3, an enzyme that regulates thyroid hormone availability, and downregulate genes encoding components of retinoic acid (RA) uptake and signaling. The aim of the current studies was to identify mechanisms by which seasonal changes in thyroid hormone and RA signaling from tanycytes might ultimately regulate appetite and energy expenditure. proVGF is one of the most abundant peptides in the mammalian brain, and studies have suggested a role for VGF-derived peptides in the photoperiodic regulation of body weight in the Siberian hamster. In silico studies identified possible thyroid and vitamin D response elements in the VGF promoter. Using the human neuroblastoma SH-SY5Y cell line, we demonstrate that RA increases endogenous VGF expression (P<0.05) and VGF promoter activity (P<0.0001). Similarly, treatment with 1,25-dihydroxyvitamin D3 increased endogenous VGF mRNA expression (P<0.05) and VGF promoter activity (P<0.0001), whereas triiodothyronine (T3) decreased both (P<0.01 and P<0.0001). Finally, intra-hypothalamic administration of T3 blocked the short day-induced increase in VGF expression in the dorsomedial posterior arcuate nucleus of Siberian hamsters. Thus, we conclude that VGF expression is a likely target of photoperiod-induced changes in tanycyte-derived signals and is potentially a regulator of seasonal changes in appetite and energy expenditure.

Change in energy expenditure and physical activity in response to aerobic and resistance exercise programs.

Exercise is considered an important component of a healthy lifestyle but there remains controversy on effects of exercise on non-exercise physical activity (PA). The present study examined the prospective association of aerobic and resistance exercise with total daily energy expenditure and PA in previously sedentary, young men. Nine men (27.0 ± 3.3 years) completed two 16-week exercise programs (3 exercise sessions per week) of aerobic and resistance exercise separated by a minimum of 6 weeks in random order. Energy expenditure and PA were measured with the SenseWear Mini Armband prior to each intervention as well as during week 1, week 8 and week 16 of the aerobic and resistance exercise program. Body composition was measured via dual x-ray absorptiometry. Body composition did not change in response to either exercise intervention. Total daily energy expenditure on exercise days increased by 443 ± 126 kcal/d and 239 ± 152 kcal/d for aerobic and resistance exercise, respectively (p < 0.01). Non-exercise moderate-to-vigorous PA, however, decreased on aerobic exercise days (−148 ± 161 kcal/d; p = 0.03). There was no change in total daily energy expenditure and PA on non-exercise days with aerobic exercise while resistance exercise was associated with an increase in moderate-to-vigorous PA during non-exercise days (216 ± 178 kcal/d, p = 0.01). Results of the present study suggest a compensatory reduction in PA in response to aerobic exercise. Resistance exercise, on the other hand, appears to facilitate non-exercise PA, particularly on non-exercise days, which may lead to more sustainable adaptations in response to an exercise program.

Ice ingestion improves cycling in hot, humid conditions with no change in energy expenditure or sweat response

Introduction: Previous research indicates that ice ingestion is an effective pre-cooling technique for improving endurance performance in the heat. Why performance is improved however, remains speculative, with little evidence to support proposed theories. This study aimed to examine the effects of pre-cooling via ice ingestion on the body's metabolic output and sweat response when exercising in hot, humid conditions.

Prospective Changes in Energy Intake, Physical Activity, and Resting Energy Expenditure during Pregnancy

Background and Purpose: Prenatal changes in energy intake (EI), physical activity (PA), and resting energy expenditure (REE) are important determinants of future health and obesity outcomes. This study examined changes in EI, PA and REE in 16 adult, pregnant women (75% Normal-weight, 15% overweight/obese) early in pregnancy (

Low levels of physical activity are associated with dysregulation of energy intake and fat mass gain over 1 year

Previous studies suggest that appetite may be dysregulated at low levels of activity, creating an energy imbalance that results in weight gain. The aim was to examine the relation between energy intake, physical activity, appetite, and weight gain during a 1-y follow-up period in a large sample of adults. Participants included 421 individuals (mean ± SD age: 27.6 ± 3.8 y). Measurements included the following: energy intake with the use of interviewer-administered dietary recalls and calculated by using changes in body composition and energy expenditure, moderate-to-vigorous physical activity (MVPA) with the use of an arm-based monitor, body composition with the use of dual-energy X-ray absorptiometry, and questionnaire-derived perceptions of dietary restraint, disinhibition, hunger, and control of eating. Participants were grouped at baseline into quintiles of MVPA (min/d) by sex. Measurements were repeated every 3 mo for 1 y. At baseline, an inverse relation existed between body weight and activity groups, with the least-active group (15.7 ± 9.9 min MVPA/d, 6062 ± 1778 steps/d) having the highest body weight (86.3 ± 13.2 kg) and the most-active group (174.5 ± 60.5 min MVPA/d, 10260 ± 3087 steps/d) having the lowest body weight (67.5 ± 11.0 kg). A positive relation was observed between calculated energy intake and activity group, except in the lowest quintile of activity. The lowest physical activity group reported higher levels of disinhibition (P = 0.07) and cravings for savory foods (P = 0.03) compared with the group with the highest level of physical activity. Over 1 y of follow-up, the lowest activity group gained the largest amount of fat mass (1.7 ± 0.3 kg) after adjustment for change in MVPA and baseline fat mass. The odds of gaining >3% of fat mass were between 1.8 and 3.8 times as high for individuals in the least-active group as for those in the middle activity group. These results suggest that low levels of physical activity are a risk factor for fat mass gain. In the current sample, a threshold for achieving energy balance occurred at an activity level corresponding to 7116 steps/d, an amount achievable by most adults. This trial was registered at clinicaltrials.gov as NCT01746186.

Energy expenditure changes after Roux-en-Y Gastric Bypass

Background Weight loss usually decreases energy expenditure (EE) because of changes in body composition (BC). The reduction in EE may contribute, in part, to long-term weight regain. Patients undergoing bariatric surgery might experience a decrease in EE, mainly due to reduced resting metabolic rate (RMR), explained by a decreased lean body mass (LBM), similarly to what occurs to patients after diet-induced weight loss.

Effects of Patrol Operation on Hydration Status and Autonomic Modulation of Heart Rate of Brazilian Peacekeepers in Haiti.

The stress of operational missions may challenge the maintenance of body homeostasis, affecting soldiers' cardiac autonomic control, promoting dehydration, and compromising performance. Therefore, we aimed to determine the effects of peacekeeper patrol operation in Haiti on soldiers' hydration status and cardiac autonomic modulation, and to determine whether fluctuations in autonomic modulation were associated with changes in hydration status, energy expenditure (EE), and aerobic fitness (V[Combining Dot Above]O2max). A group of 20 soldiers (23.5 ± 4.7 years; V[Combining Dot Above]O2max 52.9 ± 4.5 ml·kg⁻¹·min⁻¹) completed an operational patrol mission with a mean duration of 160.6 ± 28.6 minutes. Before (Pre) and after (Post) the operation, the soldiers' body masses (BMs) were measured and 5-minute heart rate interbeat (R-R) intervals were recorded at rest to estimate heart rate variability (low-frequency [LF] and high-frequency [HF] power, and sympathovagal balance [LF/HF]). During the mission, EE was estimated using heart rate (HR) monitors. Changes from Pre to Post in BM (%BM loss) and LF/HF (ΔLF/HF) were used to evaluate the soldiers' dehydration levels and autonomic modulation, respectively. The mean EE was 711.0 ± 208.7 kcal. From pre to post, increases (p < 0.01) were noted in LF normalized units (n.u.) and LF/HF and decreases (p < 0.01) were noted in BM, R-R interval, and HF n.u. The variation in ΔLF/HF correlated with EE (r = 0.49; p = 0.02), V[Combining Dot Above]O2max (r = -0.42; p = 0.05), and %BM loss (r = 0.53; p = 0.02). The results demonstrated that an operational peacekeeper patrol with an approximate duration of 160 minutes promoted both dehydration and an imbalance in the autonomic modulation of soldiers' HR. The reduction in sympathovagal balance correlated with EE, dehydration, and aerobic conditioning.

Changes in Physical Activity and Psychological Variables Following a Web-Based Motivational Interviewing Intervention: Pilot Study

BackgroundWeb-based interventions for enhancing physical activity participation are in demand for application in health care settings. Recent research suggests Web-based interventions that are based on motivational interviewing are effective to increase physical activity. It is unclear whether motivational interviewing can influence targeted psychological variables such as perceived readiness, willingness, and ability to participate in physical activity.ObjectiveThe aims of this study were to determine whether there were changes in physical activity and psychological variables associated with readiness, willingness, and perceived ability to participate in physical activity following completion of a novel Web-based intervention. The goal of the motivational interviewing–based intervention was to increase physical activity.MethodsTwenty-three underactive or inactive urban dwelling adults were recruited at a medical office for participation in a 4-session Web-based intervention lasting approximately 15 minutes per week. Sessions were based on principles of motivational interviewing. Assessment of physical activity was conducted using pedometers immediately prior to intervention participation (pre) and immediately post intervention (post1). Self-report assessments of physical activity and psychological variables were conducted using online surveys at pre, post1, and again at one month following intervention participation (post2).ResultsComparisons of pre and post1 pedometer recordings revealed significant increases in steps per day (t 22=2.09, P=.049). There were also significant changes in total physical activity energy expenditure per week (χ2 2=8.4, P=.02) and in moderate intensity physical activity energy expenditure per week (χ2 2=13.9, P<.001) over time following participation in the Web-based intervention. Significant changes in psychological variables following participation in the Web-based intervention included: (1) change in stage classification over time (χ2 2=21.5, P<.001), where the percentage of participants classified in the action or maintenance stages of change in physical activity increased over time (pre=25% [6/24], post1=71% [17/24], post2=68% [15/22]); (2) decreases in self-reported decisional balance cons (F 2,42=12.76, P<.001); (3) increases in self-reported decisional balance pros (F 2,42=16.19, P<.001); (4) increases in physical activity enjoyment (F 2,20=3.85, P=.04); and (5) increases in self-efficacy (F 2,42=3.30, P=.047).ConclusionsThe Web-based intervention piloted in this study shows preliminary promise as a tool to promote physical activity in health care settings. Additional research is needed to test the effectiveness of motivational interviewing compared to a control condition and to refine content by considering mediation by psychological variables in a larger sample.