Effect of daytime on resting energy expenditure and thermic effect of food in obese adolescents.

The aim of this study was to investigate the effect of daytime on resting energy expenditure (REE) and thermic effect of food (TEF), REE and TEF were measured in 11 obese boys (mean age +/- SD 11.9 +/- 1.6 years; body mass index 30.1 +/- 4.0 kg/m2) by indirect calorimetry (SensorMedics 2900) on two consecutive days: early in the morning (7:30 a.m.) on one day and at 12 noon on the other day or vice versa. REE was measured for 30 minutes and TEF for 180 minutes after a 600 kcal liquid meal containing 13% protein, 39% fat and 48% carbohydrates. REE measured in the morning was not statistically different from that measured at noon (2191 +/- 358 vs 2223 +/- 319 kcal/24 hours) and morning values were highly correlated with afternoon values (r2 = 0.805). Therefore we conclude that the effect of daytime is negligible for measurements of REE if the patients are in a postabsorptive state and avoid physical activity and stress 10-12 hours prior to measurements. The thermic effect of food calculated in the morning also was not statistically significantly from values found in the afternoon (8.2 +/- 8.8% in the morning and 6.6 +/- 7.5% in the afternoon). However, because of very high within-patient variability the correlation between morning and afternoon values was weaker than for REE (r2 = 0.289).     

Physical activity,total energy expenditure,and food intake in grossly obese and normal weight women

The doubly labeled water method was used to measure average daily total energy expenditure (TEE) in 10 healthy normal weight women classified as unrestrained eaters and in 10 grossly obese women. The body mass index was 20.0 ± 1.3 kg/m² in the control group and 37.4 ± 8.1 kg/m² for the obese group. TEE was measured over a 2-week period. TEE was 2,357 ± 504 kcal/day for the controls and 3,708 ± 367 kcal/day for the obese group during a cognitive-behavioral treatment. © 1995 by John Wiley & Sons, Inc.     

Effects of weight loss on substrate oxidation, energy expenditure, and insulin sensitivity in obese individuals.

To evaluate the effect of weight loss on substrate oxidation, energy expenditure, and insulin sensitivity we studied 12 obese subjects (body mass index 33.4 +/- 1.1) before and after 6 wk of a very-low-calorie diet (VLCD) with euglycemic insulin clamp in combination with indirect calorimetry. Body weight decreased from 105.3 +/- 4.6 to 94.1 +/- 4.0 kg (P less than 0.001) and fat mass from 47.2 +/- 3.6 to 37.7 +/- 3.0 kg (P less than 0.001). Total glucose disposal during insulin clamp increased from 30.4 +/- 4.3 to 38.4 +/- 4.4 mumol.kg lean body mass (LBM)-1.min-1 (P less than 0.05), insulin-stimulated glucose oxidation from 14.3 +/- 4.6 to 19.1 +/- 1.4 mumol.kg LBM-1.min-1 (P less than 0.05), and non-oxidative glucose metabolism from 16.0 +/- 3.8 to 19.3 +/- 3.6 mumol.kg LBM-1.min-1 (NS). Lipid oxidation decreased in the basal state (P less than 0.05) and during the insulin clamp (P less than 0.01). The basal rate of energy expenditure decreased from 99.1 +/- 4.6 to 88.5 +/- 2.7 kJ.kg LBM-1.min-1 (P less than 0.05) after weight reduction. A reduction in fat mass achieved by VLCD is associated with reduced lipid oxidation and, because of substrate competition, enhanced glucose oxidation. The physiological consequence is improved insulin sensitivity.     

Effect of protein ingestion on energy expenditure and substrate utilization after exercise in middle-aged women

Research suggests that ingesting protein after resistance exercise (RE) increases muscle protein synthesis and results in greater muscle gains. The effect on energy expenditure and substrate utilization, however, is unclear. This study evaluated the effect of RE and postexercise protein on recovery energy expenditure and substrate utilization in 17 women (age 46.5 +/- 1.2 y). A whey-protein supplement (120 kcal, 30 g protein) was ingested immediately after 1 bout of RE (PRO) and a noncaloric placebo after another (PLA).VO2 and respiratory-exchange ratio (RER) were measured before and for 120 min after each exercise session. RE resulted in a significant increase in VO2 that persisted through 90 min of recovery (P < 0.01) and was not affected by protein supplementation. RE significantly lowered RER, resulting in an increase in fat oxidation for both PLA and PRO (P < 0.01). For PRO, however, RER returned to baseline values earlier than for PLA, resulting in a reduced fat-oxidation response (P = 0.02) and earlier return to preexercise baseline values than for PLA. Substrate utilization was significantly different between conditions (P = 0.02), with fat contributing 77.76% +/- 2.19% for PLA and 72.12% +/- 2.17% for PRO, while protein oxidation increased from 17.18% +/- 1.33% for PLA to 20.82% +/- 1.47% for PRO. Postexercise protein did not affect energy expenditure, but when protein was available as an alternate fuel fat oxidation was diminished. Based on these findings it might be beneficial for middle-aged women to delay protein intake after RE to maximize fat utilization.     

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.     

Short-term effects of a progestational contraceptive drug on food intake, resting energy expenditure, and body weight in young women

BACKGROUND: Studies showed that hormonal fluctuations that occur over the human menstrual cycle affect energy intake and expenditure. However, little is known about the possible effects on body weight regulation that may arise when these cyclic changes are suppressed with hormonal contraceptives. OBJECTIVE: The aim of this study was to examine how a progestational contraceptive drug (depot medroxyprogesterone acetate) affects food intake, resting energy expenditure (REE), and body weight in young women. DESIGN: Twenty normal-weight women were tested in a single-blind, placebo-controlled experiment. Body weight, REE, and 3-d food intake (food provided) were measured in the follicular and luteal phases of 2 menstrual cycles before a single injection of depot medroxyprogesterone or saline solution was administered. Measurements were also taken 4 times after injection: in the luteal and follicular phases of 2 cycles in the placebo group and 2 wk apart (to mimic timing of the menstrual phases) in the drug group. RESULTS: Before injection, the phase of the menstrual cycle affected both energy intake and REE. The study participants consumed more energy (4.3%; P = 0.02) and expended more energy at rest (4.3%; P = 0.0002) in the luteal phase than in the follicular phase. Comparison of pre- and postinjection means showed that treatment with the contraceptive drug had no significant effects on energy intake, REE, or body weight. CONCLUSIONS: This study showed that, although phases of the menstrual cycle affected energy intake and REE, depot medroxyprogesterone acetate did not alter energy intake or expenditure or cause weight gain in young women.     

Effect of a high-protein, very-low-calorie diet on resting metabolism, thyroid hormones, and energy expenditure of obese middle-aged women

A 4-6 mo study was conducted to examine effects of a very-low-calorie, high-protein diet and realimentation on energy expenditure, resting metabolic rate (RMR), and serum thyroid hormones of obese women aged 30-54 yr. Fifteen healthy women, greater than or equal to 126% ideal body weight, were placed on the diet (420 kcal/day) and lost an average of 1.1 kg/wk until a predetermined goal weight was attained. RMR, triiodothyronine (T3), and reverse T3 decreased significantly (p less than 0.05). Thyroxine remained unchanged. Upon gradual realimentation onto solid foods, all metabolic parameters increased significantly within 5 wk toward pre-diet baseline values, but RMR (kcal/h) and T3 values remained significantly below pre-study values. Estimates of mean energy expenditure, utilizing a technique based on energy intake and body composition changes, averaged 1719 kcal/day during the diet period.     

Energy expenditure and body composition during weight reduction in hyperplastic obese women

The energy expenditure and body composition changes in out-patients during a long-term weight reduction with a diet recommended to provide 1100 kcal were studied in eight hyperplastic obese women. The study was focused on finding plausible explanations for the decreasing weight loss rate after several weeks of successful weight reduction. Using a heart rate monitoring method, the energy expenditure was measured four times at selected intervals during the study. Then, the energy intake was calculated on the basis of three dietary recordings lasting from 4 to 7 days. The recorded energy intake increased at the end of the weight reduction, but no changes in daily energy expenditure were found. The oxygen consumption during standardized cycling, walking, and domestic work decreased, but when the patient was at rest, no changes occurred during the weight reduction. The weight loss predicted from the energy balance and body composition changes was considerably greater than the actually determined weight loss. Large discrepancies were found after 5 weeks on the weight reducing regimen between the recorded dietary intake and what could be calculated from urinary nitrogen losses. With the available methods for determining energy intake and expenditure, it was considered impossible to fully explain the reason for the weight plateau observed after long-term weight reduction in out-patients.     

Effect of meal frequency on the thermic effect of food in women

The effect of meal frequency on the thermic effect of food (TEF), also referred to as dietary induced thermogenesis (DIT), was investigated in eighteen non-obese female subjects. Their metabolic rate before and after consuming the test meal was measured by open circuit indirect calorimetry using the Douglas bag technique, while the subjects were in the resting state (lying down). Eight subjects consumed a high carbohydrate-low fat (HCLF) meal providing 70, 19 and 11 per cent of the energy content from carbohydrate, fat and protein, respectively, and ten other subjects consumed a low carbohydrate-high fat (LCHF) meal providing 24, 65 and 11 per cent of the energy from carbohydrate, fat and protein, respectively. On two separate occasions, each subject consumed the appropriate diet either as one large meal containing 5040 kJ (1200 kcal) or as two smaller meals each containing 2520 kJ (600 kcal). TEF values were calculated for 6 h after the test meal and the mean values after consuming the HCLF meal were 377.0 +/- 30.0 kJ (90 +/- 7.2 kcal) and 381.0 +/- 26.5 kJ (91.0 +/- 6.3 kcal) for the one meal and the two meals, respectively. The mean TEF values for the subjects who consumed the LCHF meal wre 356.0 +/- 23.0 kJ (85.0 +/- 5.5 kcal) and 340 +/- 15.9 kJ (81.0 +/- 3.8 kcal) for the one meal and the two meals, respectively. No significant differences were found between the two feeding regimens (HCLF, P = 0.94; LCHF, P = 0.64) as well as between the compositions (P = 0.57). Thus, meal frequency and meal composition did not seem to influence the TEF.     

Whole-body protein turnover and resting energy expenditure in obese, prepubertal children

BACKGROUND: Obesity is becoming more frequent in children; understanding the extent to which this condition affects not only carbohydrate and lipid metabolism but also protein metabolism is of paramount importance. OBJECTIVE: We evaluated the kinetics of protein metabolism in obese, prepubertal children in the static phase of obesity. DESIGN: In this cross-sectional study, 9 obese children (x +/- SE: 44+/-4 kg, 30.9+/-1.5% body fat) were compared with 8 lean (28+/-2 kg ,16.8+/-1.2% body fat), age-matched (8.5+/-0.2 y) control children. Whole-body nitrogen flux, protein synthesis, and protein breakdown were calculated postprandially over 9 h from 15N abundance in urinary ammonia by using a single oral dose of [15N]glycine; resting energy expenditure (REE) was assessed by indirect calorimetry (canopy) and body composition by multiple skinfold-thickness measurements. RESULTS: Absolute rates of protein synthesis and breakdown were significantly greater in obese children than in control children (x +/- SE: 208+/-24 compared with 137+/-14 g/d, P < 0.05, and 149+/-20 compared with 89+/-13 g/d, P < 0.05, respectively). When these variables were adjusted for fat-free mass by analysis of covariance, however, the differences between groups disappeared. There was a significant relation between protein synthesis and fat-free mass (r = 0.83, P < 0.001) as well as between protein synthesis and REE (r = 0.79, P < 0.005). CONCLUSIONS: Obesity in prepubertal children is associated with an absolute increase in whole-body protein turnover that is consistent with an absolute increase in fat-free mass, both of which contribute to explaining the greater absolute REE in obese children than in control children.     

Effect of acclimation on resting energy expenditure measurements.

BACKGROUND: Development of an acclimation protocol for use when measuring resting energy expenditure (REE) would simplify and standardize data collection. The purpose of this study was to determine if our 2 metabolic carts could be used interchangeably and to determine if excluding the first 3 or 5 minutes of data collected as an acclimation period would significantly improve the coefficients of variation (CVs) for oxygen consumed (VO(2)) and carbon dioxide produced (VCO(2)) when performing REE assessments with our metabolic cart systems. METHODS: Thirteen healthy, nonsmoking adults ranging in age from 32 to 45 years, with activity levels ranging from sedentary to highly active, participated. Indirect calorimetry was performed twice in the morning after 30 minutes of supine resting. Subjects had fasted for 12 hours, and did not exercise within the last 24 hours. The system order for testing was randomized for the first measurement. When the first measurement was completed, subjects were crossed over for measurement using a second metabolic cart. RESULTS: The CVs for VO(2) and VCO(2) were significantly lower when excluding the first 3 (VO(2), p = .0005), (VCO(2), p = .0024) or 5 minutes (VO(2), p = .0001, VCO(2), p = .0021) of data compared with no exclusions. No significant differences in CVs between the 3- and 5-minute exclusions were found for VO(2) (p = .3224) or VCO(2) (p = .2255). CONCLUSIONS: Clearly, our machines cannot be used interchangeably within a study. An acclimation period improves CVs of VO(2) and VCO(2.) The similarities in CVs led us to adopt a 3-minute acclimation period for measuring REE.     

Effect of energy and protein intake and exercise intensity on the thermic effect of food

The effect of energy content and protein concentration of a test meal and exercise intensity on the thermic effect of food (TEF) was examined. TEF was measured in eight men in response to meals representing 15, 30, and 45% of daily energy requirement; protein concentrations of 15, 30, and 45% of energy of the meal, and exercise intensities of 35, 50, and 65% of maximum capacity. In response to energy content of the meals, total 3-h TEF (mean +/- SEM) 4.0 +/- 0.83, 9.7 +/- 1.15, and 10.8 +/- 0.79 1 O2 for the 15, 30, and 45% meals, respectively, indicating a positive linear and a negative quadratic relationship. Although the 15% protein meal resulted in the smallest TEF, 150-270 min after the meal, total 5-h increase in oxygen consumption did not differ among the three protein meals. Exercise intensity did not alter TEF. Energy content of the test meal had the greatest effect on TEF.     

Effects of recombinant human leptin treatment as an adjunct of moderate energy restriction on body weight,resting energy expenditure and energy intake in obese humans

We explored the effects of recombinant human leptin (rL) as an adjunct of mild energy restriction (2092 kJ/day less than needed) in the treatment of obese humans as part of a larger multicentre trial. In a double blind, randomised, placebo (P)-controlled design, the effects of 10 mg of rL once daily vs twice daily (rL OD/BID, by s.c. injection) upon body weight, resting energy expenditure (REE) and energy intake were compared. The study groups comprised 9 (P), 15 (rL OD) and 6 (rL BID) healthy subjects (body mass index 27.5-35 kg/m2). We observed in both groups treated with rL a decline of body weight. [2.8+/-1.1 kg (P), 5.2+/-0.9 kg (rL OD), 7.9+/-1.4 kg (rL BID), p < 0.035]. No significant effects of rL treatment upon energy intake or REE were observed. However, rL tended to reduce the decline of energy expenditure associated with energy restriction, whereas the tendency of energy intake to increase back to baseline levels in placebo-treated subjects was largely prevented in subjects treated with rL. Thus, rL appears to enhance the loss of body weight in obese humans in a dose-dependent fashion if prescribed as an adjunct of energy restriction. This effect might be mediated by rL ability to counteract the behavioural and metabolic adaptations that accompany weight loss attempts.     

Predicted and measured resting energy expenditure in healthy young women

Basal energy expenditure (BEE) was either measured by indirect calorimetry or predicted by different formulae in 104 young women: 74 lean and overweight subjects (normal weight, NWt) and 30 obese subjects. The predictive equations were based on weight alone (Owen, FAO-1, Schofield-1) or on weight and height (Harris-Benedict, Mifflin, Kleiber, and again FAO-2 and Schofield-2). With the exception of the Owen equation all the equations over-estimated measured BEE in both study groups. The ratio between measured and predicted value (% MP) varied between 102.3 (Owen) and 87.7 (Kleiber) in the NWt subjects and between 113.2 (Owen) and 89.3 (Schofield-1) in the obese subjects. The range including 95% of the predicted-measured differences (PMdiff) was larger than 1700 kJ/d in the NWt group and 2300 kJ/d in the obese group. In both study groups most of the equations showed a significant relationship between PMdiff and/or % MP with body weight and the magnitude of BEE. In conclusion, these equations are of little help in predicting BEE in a single subject and should be used with caution when assessing energy requirements in populations or groups of subjects.     

孕前超重/肥胖的妊娠期糖尿病孕妇血糖管理：基于静息能量消耗计算每日总能量消耗

目的探讨基于静息能量消耗(REE)计算每日总能量消耗(TEE)，对孕前超重/肥胖的妊娠期糖尿病(GDM)孕妇血糖管理意义。 方法选择2018年6月至2019年6月，于首都医科大学附属北京潞河医院产科"糖尿病一日门诊"就诊时，被诊断为孕前超重/肥胖的67例GDM孕妇为研究对象。按照其首次就诊时间的奇、偶周，将其分为研究组(n＝34，首次就诊时间为奇数周者)和对照组(n＝33，首次就诊时间为偶数周者)。采用成组t检验对2组孕妇年龄、孕次、孕期体重增加值、新生儿出生体重、空腹血糖、餐后2 h血糖等进行统计学分析。采用Mann-Whitney U检验对2组孕妇分娩孕龄、产次等进行统计学分析。采用χ²检验、Fisher确切概率法、连续性校正χ²检验对2组孕妇尿酮体阳性率、巨大儿发生率等进行统计学分析。本研究经首都医科大学附属北京潞河医院医学伦理委员审核批准(审批文号：2018-LHKY-027-02)，并与所有受试者签署知情同意书。 结果①2组GDM孕妇年龄、孕次、产次、分娩孕龄及孕前人体质量指数(BMI)构成比比较，差异均无统计学意义(P>0.05)。②研究组孕妇TEE为(1 532.6±301.9)kcal/d，显著低于对照组的(1 824.1±313.2) kcal/d，并且差异有统计学意义(t＝3.311、P＝0.002)；2组孕妇血糖达标情况构成比比较，差异亦有统计学意义(P＝0.040)。③研究组孕妇孕期体重增加值、糖化血红蛋白(HbA1c)水平和新生儿出生体重分别为(13.4±6.2)kg、(5.6±0.3)%和(3 287.5±577.1)g，明显低于对照组的(18.2±4.8)kg、(6.2±0.2)%和(3 632.8±490.6)g，并且差异均有统计学意义(t＝2.235、P＝0.031，t＝2.882、P＝0.047，t＝2.121、P＝0.039)。 结论基于REE估算的TEE，较通用系数法估算的TEE，更接近于孕前超重/肥胖GDM孕妇的实际能量需求。因此，基于REE估算的TEE更有利于对孕前超重/肥胖的GDM进行孕期血糖管理。     

Effect of chewing gum containing nicotine and caffeine on energy expenditure and substrate utilization in men

BACKGROUND: Nicotine replacement therapy limits weight gain after smoking cessation. This finding is partly attributable to the thermogenic effect of nicotine, which may be enhanced by caffeine. OBJECTIVE: We assessed the acute thermogenic effects of chewing gum containing different doses of nicotine and caffeine. DESIGN: This randomized, double-blind, placebo-controlled, crossover study included 12 healthy, normal-weight men (aged 18-45 y). Energy expenditure was measured with indirect calorimetry before and 2.5 h after subjects chewed each of 7 different types of gum containing the following doses of nicotine/caffeine: 0/0, 1/0, 2/0, 1/50, 2/50, 1/100, and 2/100 mg/mg. RESULTS: The thermogenic responses (increases over the response to placebo) were 3.7%, 4.9%, 7.9%, 6.3%, 8.5%, and 9.8%, respectively, for the gums containing 1/0, 2/0, 1/50, 2/50, 1/100, and 2/100 mg nicotine/mg caffeine (P < 0.05 for all). Adding caffeine to 1 and 2 mg nicotine significantly enhanced the thermogenic response, but changing the caffeine dose (from 50 to 100 mg) did not change the thermogenic effect. None of the combinations changed the respiratory quotient compared with placebo, which indicates that glucose and fat oxidation rates were increased to a similar extent. Side effects occurred only with 2 mg nicotine. CONCLUSIONS: One milligram of nicotine has a pronounced thermogenic effect, which can be increased by approximately 100% by adding 100 mg caffeine. Increasing the nicotine dose to 2 mg does not increase the thermogenic effect but produces side effects in most subjects. Caffeine may be useful in preventing weight gain after smoking cessation if its thermogenic effect can be used to enhance nicotine's effect on long-term energy balance.     

Determinants of free-living energy expenditure in normal weight and obese women measured by doubly labeled water

Total free-living energy expenditure (TEE) was measured in 9 normal weight controls and 5 obese women using the doubly labeled water (DLW) method. Resting energy expenditure (REE) and the thermic effect of food (TEF) were measured by indirect calorimetry and the energy cost of physical activity (PA) calculated by deduction, in order to quantify the components and identify determinants of free-living TEE. Although REE was quantitatively the major component of TEE in both groups, PA best explained the variability, contributing 76% to the variance in free-living TEE. The obese women had elevated values for TEE (12397 +/- 2565 vs. 8339 +/- 1787 kJ/d, mean +/- SD; p < 0.005), compared with the control women. PA (5071 +/- 2385 vs. 2552 +/- 1452; p < 0.05) and REE (6393 +/- 678 vs. 5084 +/- 259; p < 0.0005) were also raised in the obese, whereas TEF was not significantly different between the groups, accounting for 7.6% of energy expenditure for the obese and 8% for the control subjects. Body weight was the single best determinant of mean daily free-living TEE across both groups. We conclude that PA and body weight are the main determinants of free-living TEE.