Decrease In Resting Energy Expenditure Research Articles

Metabolic adaptation to caloric restriction and subsequent refeeding: the Minnesota Starvation Experiment revisited

Adaptive thermogenesis (AT) is the fat-free mass (FFM)-independent reduction of resting energy expenditure (REE) to caloric restriction (CR). AT attenuates weight loss and favors weight regain. Its variance, dynamics, and control remain obscure. Our aims were to address the variance and kinetics of AT, its associations with body composition in the context of endocrine determinants, and its effect on weight regain. Thirty-two nonobese men underwent sequential overfeeding (1 wk at +50% of energy needs), CR (3 wk at -50% of energy needs), and refeeding (2 wk at +50% of energy needs). AT and its determinants were measured together with body composition as assessed with the use of quantitative magnetic resonance, whole-body MRI, isotope dilution, and nitrogen and fluid balances. Changes in body weight were +1.8 kg (overfeeding), -6.0 kg (CR), and +3.5 kg (refeeding). CR reduced fat mass and FFM by 114 and 159 g/d, respectively. Within FFM, skeletal muscle (-5%), liver (-13%), and kidneys (-8%) decreased. CR also led to reductions in REE (-266 kcal/d), respiratory quotient (-15%), heart rate (-14%), blood pressure (-7%), creatinine clearance (-12%), energy cost of walking (-22%), activity of the sympathetic nervous system (SNS) (-38%), and plasma leptin (-44%), insulin (-54%), adiponectin (-49%), 3,5,3'-tri-iodo-thyronine (T3) (-39%), and testosterone (-11%). AT was 108 kcal/d or 48% of the decrease in REE. Changes in FFM composition explained 36 kcal, which left 72 kcal/d for true AT. The decrease in AT became significant at ≤3 d of CR and was related to decreases in insulin secretion (r = 0.92, P < 0.001), heart rate (r = 0.60, P < 0.05), creatinine clearance (r = 0.79, P < 0.05), negative fluid balance (r = 0.51, P < 0.01), and the free water clearance rate (r = -0.90, P < 0.002). SNS activity and plasma leptin, ghrelin, and T3 and their changes with CR were not related to AT. During early weight loss, AT is associated with a fall in insulin secretion and body fluid balance. This trial was registered at clinicaltrials.gov as NCT01737034.

Effects of Incremental Dietary Macronutrient Changes on Fat Oxidation and Body Composition

Despite evidence that low-carbohydrate diets (LCD) can improve metabolic syndrome (MetS) characteristics and risk for cardiovascular disease, concerns remain regarding the potential deleterious effects of higher fat intake. If higher fat intake (in the context of lower carbohydrate intake) is accompanied by higher fat oxidation, there would likely be more efficient fat loss and improved health parameters. PURPOSE: Our aim was to examine how diets spanning a broad range of carbohydrate levels ranging from very low (<50 g/day) to current dietary guidelines (∼350 g/day) affect substrate oxidation patterns and changes in body composition within the same person while keeping caloric and protein intake constant. METHODS: After an initial 3-wk run-in LCD, 16 adults with MetS (age 44.9 ± 9.9 yr, BMI 37.9 ± 6.3 kg/m2) were fed six sequential moderately hypocaloric 3-wk diets that progressively increased carbohydrate (CHO) (from 47 to 344 g/day) with concomitant decreases in total fat. Body composition was determined by dual-energy X-ray absorptiometry (DXA) and respiratory quotient (RQ), fat oxidation, and resting energy expenditure (REE) were determined by indirect calorimetry after each diet phase. RESULTS: Subjects lost significantly more fat mass (-2.32±1.53 kg) on the free-living LCD phase, but overall fat mass loss was variable between subjects and on average less than expected from the calculated caloric deficit (-8.3±4.5 vs -12.7±15.8 kg, respectively). There was a significant decrease in REE, but no significant change in relative REE (kcals/kg/day). Fat oxidation rates significantly increased when consuming diets with 7% CHO, but decreased to below baseline by the highest CHO phase. RQ decreased on the LCD (0.75±0.04), and increased linearly as CHO increased, up to 0.84 ±0.05. Body mass was significantly correlated with CHO consumption (r=0.49), insulin (r=0.34), fat consumption (r=-0.49) and ketones (r=-0.46). CONCLUSION: These findings suggest that it is difficult to estimate weight loss within an individual, even with a constant caloric deficit, since individuals vary in their substrate oxidation response to reintroduction of dietary carbohydrate. Those who can maintain a higher fat oxidation to a greater extent as dietary carbohydrates are increased (and fat decreased) may possess an enhanced ability for fat loss on higher carbohydrate diets.

Independent and combined influence of the FTO rs9939609 and MC4Rrs17782313 polymorphisms on hypocaloric diet induced changes in body mass and composition and energy metabolism in non-morbid obese premenopausal women.

To examine the independent and combined influence of the FTOrs9939609 and the MC4Rrs17782313 polymorphisms on changes in fat mass (FM), resting energy expenditure (REE), leptin, and thyrotropin (TSH) levels, after a 12-week energy-restricted diet intervention in non-morbid premenopausal obese women. Fat mass (dual X-ray absorptiometry), REE (indirect calorimetry) and plasma leptin and thyrotropin levels were measured (before and after the intervention) in 77 obese (BMI: 33.9 ± 2.8 kg/m(2)) women (age: 36.8 ± 7.0y). There were no significant differences across FTOrs9939609 genotype groups (TT vs. A allele carriers, Ps>0.1) on changes in body mass (-8.6 ± 3.2% vs. -8.7 ± 3.3 %), FM (12.8 ± 4.7% vs. -12.9 ± 6.3%), REE (-11.3 ± 4.7 vs. -9.4 ± 8.1%), leptin (-34.1 ± 25.1% vs. -43.5 ± 24.1%) or TSH (5.2 ± 34.5% vs. -1.7 ± 27.1%) levels. Moreover, it was not observed any significant difference on changes in body mass (-8.6 ± 3.6% vs. -8.9 ± 2.6%), FM (-12.7 ± 6.1% vs. -13.4 ± 5.3%), REE (-9.8 ± 7.4% -9.4 ± 9.4%), leptin (-39.0 ± 26.9% vs. -44.8 ± 18.4%) or TSH (-1.0 ± 30.0% vs. 1.5 ± 26.5%) levels between non-C allele carriers and C allele carriers of the MC4Rrs17782313 (Ps>0.3). Finally, there were no significant difference on changes in body mass and composition, REE, leptin or TSH levels among non-risk allele carriers, carriers of the C allele risk of the MC4Rrs17782313, carriers of the A allele of the FTOrs9939609 and carriers of both risk alleles after the 12-week energy-restricted diet intervention (Ps>0.1). Carrying the A risk allele of the FTOrs9939609 and/or the C risk allele of the MC4Rrs17782313 did not influence body mass and FM loss, or REE decrease in obese women after a 12-week energy-restricted diet intervention.

Effect on Resting Energy Expenditure of Three Maintenance Diets

Patients who diet often regain all or part of lost weight, possibly because calorie restriction induces a decline in resting energy expenditure (REE). Whether the composition of the maintenance diet affects this decrease in REE was assessed in 21 overweight and obese adults …

Influence of water drinking on resting energy expenditure in overweight children

It was previously demonstrated that drinking water significantly elevates the resting energy expenditure (REE) in adults, and that low water intake is associated with obesity and lesser success in weight reduction. This study addressed the potential of water drinking to increase the REE in children, as an additional tool for weight management. To examine the effect of drinking water on the REE of overweight children. A total of 21 overweight, otherwise-healthy children (age 9.9±1.4 years, 11 males) drank 10 ml kg(-1) cold water (4 °C). REE was measured before and after water ingestion, for 66 min. The main outcome measure was the change in mean REE from baseline values. Immediately after drinking water, there was a transient decrease in REE, from a baseline value of 3.32±1.15 kilojoule (kJ) per min to 2.56±0.66 kJ per min at minute 3 (P=0.005). A subsequent rise in REE was then observed, which was significantly higher than baseline after 24 min (3.89±0.78 kJ/min (P=0.021)), and at most time points thereafter. Maximal mean REE values were seen at 57 min after water drinking (4.16±1.43 kJ per min (P=0.004)), which were 25% higher than baseline. REE was significantly correlated with age, height, weight and fat-free mass; the correlations with maximal REE values after water drinking were stronger than with baseline REE values. This study demonstrated an increase of up to 25% in REE following the drinking of 10 ml kg(-1) of cold water in overweight children, lasting for over 40 min. Consuming the recommended daily amount of water for children could result in an energy expenditure equivalent to an additional weight loss of about 1.2 kg per year. These findings reinforce the concept of water-induced REE elevation shown in adults, suggesting that water drinking could assist overweight children in weight loss or maintenance, and may warrant emphasis in dietary guidelines against the obesity epidemic.

Focus on the assessment of physical activity level of patients with cancer cachexia enrolled in a randomized phase III clinical trial.

9164 Background: Physical activity is an important component of the physical and social domains of quality of life (QL); therefore any restoration of physical activity level (PAL) towards a normal level may translate into an improvement in QL of cachectic cancer patients. Purpose: We carried out a phase III randomized study to establish which was the most effective and safest treatment to improve the primary endpoints of cancer cachexia and among them we have selected as the most relevant PAL. Patient total daily PAL and associated energy expenditure was assessed with an electronic device (SenseWear PRO2 Armband), shown in some validation studies to be able to assess appropriately the total energy expenditure (TEE) and its specific components, resting energy expenditure (REE) and active energy expenditure (AEE). AEE was recorded at an intensity ≥ 3.0 metabolic equivalents corresponding to a moderate physical activity. The armband is able to identify the specific type of patient physical activity in such a way to attribute to it a “functional quality.” Methods: Seventy out of 332 patients with cancer cachexia enrolled in the study were assessed for total daily PAL before and after treatment. The study design planned to randomly assign eligible patients to 1 of 5 arms of treatment: 1) medroxyprogesterone 500 mg/d or megestrol acetate 320 mg/d; 2) oral supplementation with 2 g EPA; 3) L-carnitine 4 g/d; 4) thalidomide 200 mg/d; 5) a combination of the above. Treatment duration: 4 months. Results: Total daily PAL showed that TEE and AEE increased significantly in arm 5 (TEE from 1291 kcal/die to 1649 kcal/die, p=0.04 and AEE from 93.8 kcal/die to 155 kcal/die, p=0.032) with a concomitant significant decrease of REE (from 1227 ± 439 to 1067 ± 181 kcal/die, p=0.044). The primary endpoints LBM (by DEXA) and fatigue improved significantly in arm 5. Toxicity was substantially negligible, comparable between treatment arms. Conclusions: The present study showed that the combination regimen was the only effective treatment in improving patient total daily PAL. Our trial shows that PAL monitoring provides a new dimension in the assessment of the comprehensive quality of life of cachectic cancer patients. No significant financial relationships to disclose.

Brain and high metabolic rate organ mass: contributions to resting energy expenditure beyond fat-free mass

The degree to which interindividual variation in the mass of select high metabolic rate organs (HMROs) mediates variability in resting energy expenditure (REE) is unknown. The objective was to investigate how much REE variability is explained by differences in HMRO mass in adults and whether age, sex, and race independently predict REE after adjustment for HMRO. A cross-sectional evaluation of 55 women [30 African Americans aged 48.7 +/- 22.2 y (mean +/- SD) and 25 whites aged 46.4 +/- 17.7 y] and 32 men (8 African Americans aged 34.3 +/- 18.2 y and 24 whites aged 51.3 +/- 20.6 y) was conducted. Liver, kidney, spleen, heart, and brain masses were measured by magnetic resonance imaging, and fat and fat-free mass (FFM) were measured by dual-energy X-ray absorptiometry. REE was measured by indirect calorimetry. REE estimated from age (P = 0.001), race (P = 0.006), sex (P = 0.31), fat (P = 0.001), and FFM (P < 0.001) accounted for 70% (adjusted (2)) of the variability in REE. The addition of trunk HMRO (P = 0.001) and brain (P = 0.006) to the model increased the explained variance to 75% and rendered the contributions of age, sex, and race statistically nonsignificant, whereas fat and FFM continued to make significant contributions (both P < 0.05). The addition of brain to the model rendered the intercept (69 kcal . kg(-1) . d(-1)) consistent with zero, which indicated zero REE for zero body mass. Relatively small interindividual variation in HMRO mass significantly affects REE and reduces the role of age, race, and sex in explaining REE. Decreases in REE with increasing age may be partly related to age-associated changes in the relative size of FFM components.

Macronutrient-specific effect of FTO rs9939609 in response to a 10-week randomized hypo-energetic diet among obese Europeans

The A risk allele of rs9939609 of the fat mass- and obesity-associated gene (FTO) increases body fat mass. To examine whether FTO rs9939609 affects obese individuals' response to a high-fat, low-carbohydrate (CHO) (HF) or low-fat, high-CHO (LF), hypo-energetic diet and whether the effect of the FTO variant depends on dietary fat and CHO content. In a 10-week, European, multi-centre dietary intervention study 771 obese women and men were randomized to either LF (20-25% of energy (%E) from fat, 60-65%E from CHO) or HF (40-45%E from fat, 40-45%E from CHO), hypo-energetic diet (measured resting metabolic rate multiplied by 1.3-600 kcal day(-1)). Body weight, fat mass (FM), fat-free mass (FFM), waist circumference (WC), resting energy expenditure (REE), fasting fat oxidation as % of REE (FatOx), insulin release (HOMA-beta) and a surrogate measure of insulin resistance (HOMA-IR) were measured at baseline and after the intervention. In all, 764 individuals were genotyped for FTO rs9939609. For A-allele carriers the drop-out rate was higher on HF than LF diet (in AT, P=0.002; in AT/AA combined, P=0.003). Among those individuals completing the intervention, we found no effect of FTO rs9939609 genotype on Deltaweight, DeltaFM, DeltaFFM, DeltaWC or DeltaFatOx. However, participants with TT had a smaller reduction in REE on LF than on HF diet (75 kcal/24 h; interaction: P=0.0055). These individuals also showed the greatest reduction in HOMA-beta and HOMA-IR (interaction: P=0.0083 and P=0.047). The FTO rs9939609 may interact with the macronutrient composition in weight loss diets in various ways; carriers of the A allele on LF diet appear to have a lower risk for drop out, and TT individuals have a smaller decrease in REE and greater decrease in HOMA-beta and HOMA-IR on LF than on HF diet.

Authors' Response to Letter

To the Editor: We are grateful to Beattie and Wiskin for taking an interest in our work. We agree that the area of energy requirements in paediatric inflammatory bowel disease (IBD) is controversial and that further work is necessary to determine the best nutritional management of children with IBD. We still believe that our data support the argument against the simple division of resting energy expenditure (REE) by fat-free mass (FFM) to adjust for differences in body composition in any population, and that raising the denominator to the power of 0.5 was a valid way of achieving this aim in the IBD cohort we studied. Our conclusion differs from that of Azcue et al (1), but it is nonetheless appropriate because their conclusion was drawn from inappropriate data expression. We clearly demonstrated that when REE is divided by FFM a negative relation is produced whereby those individuals with higher FFM display lower REE and those with lower FFM display higher REE. Following this model, it would be expected that the Crohn group would display higher REE per kilogram of FFM due to having lower FFM than controls, as we state in our original article. Azcue et al compared children with Crohn disease and anorexia nervosa and their findings do not necessarily fit our model. However, they also stated that this comparison is potentially confounded by the older age and exclusive female sex of the children with anorexia. Beattie and Wiskin also interpret the findings of Varille et al (2) as suggesting the reduction in REE between pre- and postsurgical adolescents with Crohn disease is indicative of increased inflammation presurgery preventing the physiological downregulation of REE associated with poor nutrition. Although a valid interpretation, it is contrary to Varille and colleagues own conclusion, being that the decrease in REE postsurgery is related to the actual removal of gut rather than the impact of inflammation. Also, as suggested by Beattie and Wiskin, our work indicates the raised REE per kilogram of FFM reported in the Crohn disease group is possibly due to inappropriate expression of the raw data because the disease group had a lower FFM than did the controls. Therefore, we agree that expression of data in an appropriate manner is necessary to answer the important question of how REE changes in individuals with IBD, and we hope that our original study has contributed to this literature.

Hypermetabolism in Gaucher disease type I is not associated with altered thyroid hormone levels

Type I Gaucher disease (OMIM 231000) is an inherited storage disorder in which deficiency of the enzyme glucocerebrosidase (EC 32145) leads to accumulation of glucocerebroside in lysosomes of macrophages. These storage cells are present in liver, spleen and bone marrow resulting in hepatosplenomegaly, cytopenia and bone complications. Metabolic abnormalities in Gaucher patients include hypermetabolism, possibly caused by elevated levels of pro-inflammatory cytokines. Nonthyroidal illness (NTI) is a combination of changes in circulating thyroid hormone levels (decreased T(3), elevated rT(3), normal or mildly depressed TSH) present in different illnesses and might be an adaptation to protect the organism from harmful catabolic effects of hypermetabolism. The hypermetabolism and the elevated cytokine levels in Gaucher disease led us to hypothesize that the alterations in thyroid hormone levels as seen in NTI might also occur in Gaucher patients. We studied thyroid hormone levels before and during treatment in 22 adult type I Gaucher patients and resting energy expenditure (REE) and correlations with thyroid hormone levels in 12 patients. Baseline thyroid hormone levels were normal in the majority (17) of patients. No cases of nonthyroidal illness were detected. Baseline REE (kcal/kg per 24 h) was not correlated with circulating levels of T(3), rT(3) or fT(4). Treatment of Gaucher disease with enzyme replacement therapy for several years resulted in a decrease in circulating fT(4) levels. After several months of treatment most patients showed a decrease in REE. There was no correlation between the changes in REE and changes in fT(4) and T(3).

Acute effects of ingesting Java Fit™ energy extreme functional coffee on resting energy expenditure and hemodynamic responses in male and female coffee drinkers

BackgroundThe purpose of this study was to examine the effects of a functional coffee beverage containing additional caffeine, green tea extracts, niacin and garcinia cambogia to regular coffee to determine the effects on resting energy expenditure (REE) and hemodynamic variables.MethodsSubjects included five male (26 ± 2.1 y, 97.16 ± 10.05 kg, 183.89 ± 6.60 cm) and five female (28.8 ± 5.3 y, 142.2 ± 12.6 lbs) regular coffee drinkers. Subjects fasted for 10 hours and were assessed for 1 hour prior (PRE) and 3 hours following 1.5 cups of coffee ingestion [JavaFit™ Energy Extreme (JF) ~400 mg total caffeine; Folgers (F) ~200 mg total caffeine] in a double-blind, crossover design. REE, resting heart rate (RHR), and systolic (SBP) and diastolic (DBP) blood pressure was assessed at PRE and 1, 2, and 3-hours post coffee ingestion. Data were analyzed by three-factor repeated measures ANOVA (p < 0.05).ResultsJF trial resulted in a significant main effect for REE (p < 0.01), SBP (p < 0.01), RER (p < 0.01), and VO2 (p < 0.01) compared to F, with no difference between trials on the RHR and DBP variables. A significant interaction for trial and time point (p < 0.05) was observed for the variable REE. The JF trial resulted in a significant overall mean increase in REE of 14.4% (males = 12.1%, females = 17.9%) over the observation period (p < 0.05), while the F trial produced an overall decrease in REE of 5.7%. SBP was significantly higher in the JF trial; however, there was no significant increase from PRE to 3-hours post.ConclusionResults from this study suggest that JavaFit™ Energy Extreme coffee is more effective than Folgers regular caffeinated coffee at increasing REE in regular coffee drinkers for up to 3 hours following ingestion without any adverse hemodynamic effects.

Persistent suppression of resting energy expenditure after acute hypoxia

Resting energy expenditure (REE) is known to be influenced by various ambient conditions such as oxygen supply. Investigations in healthy subjects during acute hypoxia revealed a drop in REE, but persistent effects after hypoxia had ended have not been examined so far. Although indirect calorimetry is a well-established method to measure REE, it may lead to false conclusions when hyperventilation, rise in lactate or catecholamines, and decrease of food intake accompany hypoxia. Therefore, we determined REE in healthy men after hypoxia had ended and under conditions of controlled energy supply during a glucose clamp. In a double-blind crossover study design, we induced hypoxia for 30 minutes by decreasing oxygen saturation to 75% (vs 96% in a control session) in 13 healthy men. Indirect calorimetry was performed at baseline and 150 minutes after hypoxia had ended. Plasma glucose was held stable between 4.5 and 5.5 mmol/L, and lactate as well as catecholamine concentrations were monitored. In parallel, we measured alterations in hormones of the hypothalamic-pituitary-thyroid axis, which is one known factor mediating changes in REE. Resting energy expenditure was decreased after hypoxia (from 1656 ± 80 to 1564 ± 97 kcal/d) as compared with the normoxic control condition (1700 ± 82 to 1749 ± 79 kcal/d, P = .037), whereas the respiratory quotient remained stable ( P = .79). Plasma lactate, catecholamine levels, and the pituitary thyroid secretory activity were unchanged after hypoxia ( P > .2). Our data demonstrate that the REE decrease persists 150 minutes after acute hypoxia, indicating an adaptation of energy metabolism. This should be valued as an additive pathogenic factor in diseases with disturbed energy metabolism.

A new device for measuring resting energy expenditure (REE) in healthy subjects

Background and aim Lifestyle change targeted towards increasing daily resting energy expenditure (REE) is one of the cornerstones of obesity treatment. Measurements of energy expenditure and substrate utilization are essential to understanding the metabolic basis of obesity, and the physiological responses to perturbations in habitual food intake. REE is the largest part of human energy expenditure (60-70%) and an increase or decrease in REE would have a large impact on total energy. Accurate and easy-to-use methods for measuring REE are needed, to be applied by clinicians in daily clinical settings to assess the validity of a new instrument to estimate REE in normal weight, healthy adults. Methods Ninety-nine subjects (52 females and 47 males) (mean ± SD, age 38 ± 14 years; body mass index (BMI) 23 ± 3 kg/m 2) were tested. REE was assessed using a Sensor Medics Vmax metabolic cart with a ventilated canopy and with the SenseWear armband. Body composition, percentage fat mass (%FM) and percentage fat free mass (%FFM) were assessed by skinfold thickness measurements (SF), bio-electrical impedance analysis (BIA) and air displacement plethysmography (BOD-POD). Results No significant difference was found among measurements of FFM using the three different techniques. Both SenseWear and Sensor Medics Vmax showed a high correlation, r = 0.42 and r = 0.40 ( p < 0.0001) respectively, with BMI. No significant difference was found in mean REE between SenseWear (1540 ± 280 kcal/day) and Sensor Medics Vmax (1700 ± 330 kcal/day) ( p = ns) and the correlation between REE measured by SenseWear and Sensor Medics Vmax was high ( r = 0.86, p < 0.0001). Bland–Altman plot showed no difference in REE determination between SenseWear and Sensor Medics Vmax. %FFM determined by BOD-POD correlated with SenseWear ( r = 0.42, p < 0.0001) as well as Sensor Medics Vmax ( r = 0.38, p < 0.001). Conclusion SF, BIA and BOD-POD provide valid and reliable measurements of FFM. Our results suggest that the SenseWear armband is an acceptable device to accurately measure REE in healthy subjects. Its characteristics have the potential to reduce measurement times and make the SenseWear armband useful for epidemiological studies.

Resting energy expenditure and body composition of Labrador Retrievers fed high fat and low fat diets

A high dietary fat intake may be an important environmental factor leading to obesity in some animals. The mechanism could be either an increase in caloric intake and/or a decrease in energy expenditure. To test the hypothesis that high fat diets result in decreased resting energy expenditure (REE), we measured REE using indirect calorimetry in 10-adult intact male Labrador Retrievers, eating weight-maintenance high-fat (HF, 41% energy, average daily intake: 8018 +/- 1247 kJ/day, mean +/- SD) and low-fat (LF, 14% energy, average daily intake: 7331 +/- 771 kJ/day) diets for a 30-day period. At the end of each dietary treatment, body composition measurements were performed using dual-energy X-ray absorptiometry. The mean +/- SD REE was not different between diets (4940 +/- 361 vs. 4861 +/- 413 kJ/day on HF and LF diets respectively). Measurements of fat-free mass (FFM) and fat mass (FM) also did not differ between diets (FFM: 26.8 +/- 2.3 kg vs. 26.3 +/- 2.5 kg; FM: 3.0 +/- 2.3 vs. 3.1 +/- 1.5 kg on HF and LF diets respectively). In summary, using a whole body calorimeter, we found no evidence of a decrease in REE or a change in body composition on a HF diet compared with LF diet.

Effect of green tea on resting energy expenditure and substrate oxidation during weight loss in overweight females

We assessed the effect of ingestion of green tea (GT) extract along with a low-energy diet (LED) on resting energy expenditure (REE), substrate oxidation and body weight as GT has been shown to increase energy expenditure and fat oxidation in the short term in both animals and people. Forty-six overweight women (BMI 27.6 (sd 1.8) kg/m2) were fed in energy balance from day 1 to day 3, followed by a LED with GT (1125 mg tea catechins +225 mg caffeine/d) or placebo (PLAC) from day 4 to day 87. Caffeine intake was standardised to 300 mg/d. Energy expenditure was measured on days 4 and 32. Reductions in weight (4.19 (sd 2.0) kg PLAC, 4.21 (sd 2.7) kg GT), BMI, waist:hip ratio, fat mass and fat-free mass were not statistically different between treatments. REE as a function of fat-free mass and fat mass was significantly reduced over 32 d in the PLAC group (P<0.05) but not in the GT group. Dietary restraint increased over time (P<0.001) in both groups, whereas disinhibition and general hunger decreased (P<0.05). The GT group became more hungry over time and less thirsty, and showed increased prospective food consumption compared with PLAC (P<0.05). Taken together, the ingestion of GT along with a LED had no additional benefit for any measures of body weight or body composition. Although the decrease in REE as a function of fat-free mass and fat mass was not significant with GT treatment, whereas it was with PLAC treatment, no significant effect of treatment over time was seen, suggesting that a robust limitation of REE reduction during a LED was not achieved by GT.

Greater than predicted decrease in resting energy expenditure with age: cross-sectional and longitudinal evidence

To determine whether the age-related decrease in resting energy expenditure (REE) is explained by variations in body composition. In Study 1, adult subjects (20-70 years) from the Quebec Family Study were classified into five different age groups. Body composition was measured by hydrodensitometry to determine fat mass and fat-free mass as predictors of REE. In the youngest group of individuals these predictors were used to plot a reference regression that was then used to predict REE in the other age groups. In Study 2, this issue was investigated in a longitudinal design (6-year follow-up). Subjects were subdivided into three groups and a reference regression was plotted at the beginning of the follow-up and was then used to predict REE 6 years later in the three age groups. In Study 1, 627 adults (288 men and 339 women), aged between 20 and 70 years. In Study 2, 191 adults (93 men and 98 women). In Study 1, measured REE was 329, 302, 528 and 636 kJ/day (P < 0.0001) below predicted REE at 34, 44, 54 and 64 years, respectively. In Study 2 the most marked deviation from predicted REE in response to the 6-year follow-up in men was observed in young adults (-548 kJ/day, P < 0.001) while in women, the largest deviation occurred later in life (-720 kj/day, P < 0.001). Aging is accompanied by a decrease in REE that is significantly greater than what is predicted by variations in body composition. This decrease may reach a mean level of about 500-800 kj/day.

Oral Glutamine Supplementation Decreases Resting Energy Expenditure in Children and Adolescents With Sickle Cell Anemia.

To determine the effects of orally administered glutamine on the resting energy expenditure (REE) and nutritional status of children and adolescents with sickle cell anemia. Twenty-seven children and adolescents (13 boys, 14 girls), 5.2 to 17.9 years old (median 11.0 years), received orally administered glutamine (600 mg/kg per day) for 24 weeks. Measures of REE and other nutritional parameters were compared at baseline and 24 weeks. After 24 weeks, the patients' median REE (kcal/d) decreased by 6% (P = 0.053) as indicated by the Harris Benedict equations and by 5% (P = 0.049) as indicated by the modified equations. Patients with less than 90% ideal body weight had even greater declines in REE after 24 weeks (P < 0.03 and 0.02, respectively). Improvements in nutrition parameters and in two amino acids in the plasma were observed. After 24 weeks of orally administered glutamine, children and adolescents with sickle cell anemia had a decrease in REE and improvement in nutritional parameters. Those who were underweight had a greater decrease in REE than those of normal body weight. Lowering REE may be an effective way to improve the growth of these children and adolescents.

Impact of intravenous antibiotic therapy on total daily energy expenditure and physical activity in cystic fibrosis children with Pseudomonas aeruginosa pulmonary exacerbation.

Resting energy expenditure (REE) increases during pulmonary exacerbation by Pseudomonas aeruginosa in cystic fibrosis (CF) patients, and decreases after i.v. anti-Pseudomonas aeruginosa antibiotic therapy (IVAT). However, the impact of IVAT on total energy expenditure (TEE) is unknown. The aim of this study was to assess the changes in TEE and its main components after IVAT administered at home. Body composition measured by skinfold thickness and bio-impedance analysis, energy intake (EI) assessed by a weekly diary, REE measured by indirect calorimetry (IC), TEE assessed by a technique using 24-h heart-rate monitoring method and physical activity (PA) monitored using an activity diary (AD) were assessed in 16 patients (9 boys and 7 girls) aged 12.1 +/- 2.3 y (range, 7.1-14.6 y), before and after 28 +/- 4 d including a 14-d IVAT course. After IVAT, weight increased significantly by 1.9% (32.1 +/- 7.5 versus 32.7 +/- 7.6 kg; p < 0.05), while fat mass and fat free mass increased non significantly. EI increased by 4.6% (10,797 +/- 3039 versus 11320 +/- 3074 kJ/d; p < 0.05). TEE was not affected by IVAT (7014 +/- 1929 versus 7081 +/- 1478 kJ/d) whereas REE decreased by 4.1% (5295 +/- 909 versus 5093 +/- 837 kJ/d; p < 0.05), resulting in 9.3% increase in PA assessed by AD converted to metabolic equivalent tasks (MET) (37.0 +/- 3.1 versus 40.7 +/- 4.5 MET; p < 0.05). The improvement in nutritional status after IVAT is not related to a decrease in TEE, but probably to an increase in EI and a decrease of REE after IVAT. After IVAT, the reduction in REE is probably compensated by an increase in PA in CF patients.

Long-term changes in energy expenditure and body composition after massive weight loss induced by gastric bypass surgery

Little is known about the determinants of individual variability in body weight and fat loss after gastric bypass surgery or about the effects of massive weight loss induced by this surgery on energy requirements. The objectives were to determine changes in energy expenditure and body composition with weight loss induced by gastric bypass surgery and to identify presurgery predictors of weight loss. Thirty extremely obese women and men with a mean (+/- SD) age of 39.0 +/- 9.6 y and a body mass index (BMI; in kg/m(2)) of 50.1 +/- 9.3 were tested longitudinally under weight-stable conditions before surgery and after weight loss and stabilization (14 +/- 2 mo). Total energy expenditure (TEE), resting energy expenditure (REE), body composition, and fasting leptin were measured. Subjects lost 53.2 +/- 22.2 kg body weight and had significant decreases in REE (-2.4 +/- 1.0 MJ/d; P < 0.001) and TEE (-3.6 +/- 2.5 MJ/d; P < 0.001). Changes in REE were predicted by changes in fat-free mass and fat mass. The average physical activity level (TEE/REE) was 1.61 at both baseline and follow-up (P = 0.98). Weight loss was predicted by baseline fat mass and BMI but not by any energy expenditure variable or leptin. Measured REE at follow-up was not significantly different from predicted REE. TEE and REE decreased by 25% on average after massive weight loss induced by gastric bypass surgery. REE changes were predicted by loss of body tissue; thus, there was no significant long-term change in energy efficiency that would independently promote weight regain.

Age-related decrease in resting energy expenditure in sedentary white women: effects of regional differences in lean and fat mass

Lean mass and resting energy expenditure (REE) decrease with age. However, it is unknown whether age-related changes in regional lean and fat mass are responsible for the age-related decrease in REE. Our objective was to determine how regional lean and fat mass vary with age and whether age is independently related to REE after adjustment for regional fat and lean mass. The study was a cross-sectional evaluation of 58 white women aged 23-77 y. Regional and whole-body lean and fat mass were measured by dual-energy X-ray absorptiometry, subcutaneous abdominal tissue (SAT) and intraabdominal adipose tissue (IAF) by computed tomography, and REE by ventilated-canopy indirect calorimetry. Independent of other significant correlates, age was significantly and independently associated with greater IAF (beta = 0.49) and less leg lean mass (beta = -0.35). IAF (r = -0.28) and IAF:SAT (r = -0.31) correlated negatively with REE. REE was negatively associated with greater age (beta = -0.42), independent of changes in lean and fat mass in different parts of the body. By contrast, trunk lean (beta = 0.27) and leg fat (beta = 0.27) mass were associated with greater REE independent of age and other body-composition variables. These results suggest that trunk lean mass (presumably primarily organ tissue) is relatively resistant to age-related changes in body composition, whereas muscle mass, especially leg muscle, tends to be lost. These data also suggest that the age-related decreases in REE are not fully explained by changes in body composition.