Effects of Walking Speed on Total and Regional Body Fat in Healthy Postmenopausal Women

Introduction: This study had two aims: (1) To confirm the efficacy of exercise speed and impulse (session duration at a given speed) to produce total and abdominal fat loss in postmenopausal women, and (2) compare the exercise speed and impulse necessary for the stimulation of fat loss to the suppression of bone mineral loss. Of special interest was to compare these parameters of exercise on fat loss in the same study and with the same subjects where they were found to suppress bone mineral loss. We hypothesized that (1) more total fat will be lost with slow walking and a longer impulse than with fast speed and shorter impulse, and (2) more abdominal subcutaneous (SC) and visceral fat (VF) will be lost with fast walking speed. Materials and Methods: Fat loss and suppression of bone mineral loss were measured in the same 25 subjects after 15 weeks, and fat measurements were also taken after 30 weeks in 16 residual subjects. Study parameters were walking a 4.8 km distance 4 days/week at either 6.6 km/h (120% of ventilatory threshold (VT)) or at 5.5 km/h (101.6% of VT) and expending 300 kcal/session. Body composition (fat and lean body mass, LBM) was measured with dual-energy X-ray absorptiometry (DXA) and anthropometric methods. Results: Slow walkers in the residual group progressively lost a significant percent of total body fat over 30 weeks while no such loss occurred after 15 weeks in fast walkers in either group, supporting hypothesis 1. However, the 20% higher starting body fat in 16 residual slow relative to fast subjects suggests that exercise fat loss is greater in overweight than in lean subjects. In fast walkers, fat loss occurred after 30 weeks of training. Hypothesis 2 was not supported as both speeds led to equal VF loss in 30-week group as estimated by waist circumference (CF) confirming that VF responds to the magnitude of energy expenditure and not the walking speed. Conclusions: Total body fat is lost through walking at all speeds, but the change is more rapid, clear, and initially greater with slow walking in overweight subjects. A longer exercise impulse at a lower speed in our study initially produced greater total fat loss than a shorter one with fast walking speed. This was reversed in comparison to how the same exercise in the same subjects suppressed bone mineral loss. Data from other studies indicate that longer impulses may promote greater fat loss at both slow and high exercise speeds, and our study providing only a 4.8 km walking distance may have limited the walking impulse and the magnitude of fat loss. Increased exercise energy expenditure at either walking speed produces equivalent declines in visceral fat in postmenopausal women, and with sufficiently long impulses, should reduce disabilities associated with central obesity.     

Commercially available pedometers: considerations for accurate step counting

BACKGROUND: Many commercially available pedometers undercount, especially at slower speeds. We examined the effects of age, obesity, and self-selected walking speed on pedometer accuracy. We also compared the accuracy of piezoelectric and spring-levered pedometers at slow walking speeds. METHODS: Study 1: 259 subjects walked on a motorized treadmill at two self-selected walking speeds. Steps were counted using a spring-levered pedometer. Study 2: 32 subjects walked on a motorized treadmill at slow walking (1.0-2.6 MPH) speeds. Steps were counted using spring-levered and piezoelectric pedometers. RESULTS: Study 1: self-selected walking speed and pedometer accuracy decreased with increasing age, weight, and body mass index (BMI). Accuracy was 71% below 2.0 MPH, 74-91% between 2.0 and 3.0 MPH, and 96% above 3.0 MPH. Decreased accuracy was best predicted by increasing age. Study 2: between 1.8 and 2.0 MPH, the accuracy of the piezoelectric pedometer (>97%) exceeded that of the spring-levered pedometers (52-95%). Even at 1.0 MPH, accuracy of the piezoelectric pedometer (56.4 +/- 33.8%) was superior to the spring-levered pedometers (7-20%). CONCLUSION: Accuracy of all pedometers tested exceeded 96% at speeds 3.0 MPH, but decreased at slower walking speeds. In individuals that naturally ambulate at slower walking speeds (e.g., elderly), we recommend the use of more sensitive (e.g., piezoelectric) pedometers.     

Associations of body composition with physical performance and self-reported functional limitation in elderly men and women

To understand how body composition relates to functional impairment, the authors examined cross-sectional associations of absolute and relative measures of fat and lean mass with physical performance and self-reported functional limitation. The sample consisted of a community-based cohort of 1,655 older women and men from Sonoma, California, who had complete baseline data in 1993-1994 on body composition, physical performance, and functional limitation. Physical performance was assessed by walking speed and grip strength, while global functional limitation, across several domains, was assessed by self-report using standard questions. Lean mass and fat mass were estimated from bioelectric impedance using population-specific prediction equations derived from dual x-ray energy absorptiometry. Higher fat mass was associated with slower walking speed and greater likelihood of functional limitation, while higher lean mass was generally associated only with increased grip strength. A higher lean mass-to-fat mass ratio, a relative measure of body composition, was associated with faster walking speed and less limitation. These findings suggest that fat mass negatively impacts some domains of physical performance and overall functioning, while lean mass is less significant in absolute terms but is important relative to amount of body fat.     

A weight reduction program preserves fat-free mass but not metabolic rate in obese adolescents

OBJECTIVE: To determine the effects of a multidisciplinary weight reduction program on body composition and energy expenditure (EE) in severely obese adolescents. RESEARCH METHODS AND PROCEDURES: Twenty-six severely obese adolescents, 12 to 16 years old [mean BMI: 33.9 kg/m(2); 41.5% fat mass (FM)] followed a 9-month weight reduction program including moderate energy restriction and progressive endurance and resistance training. Body composition was assessed by DXA, basal metabolic rate by indirect calorimetry, and EE by whole-body indirect calorimetry with the same activity program over 36-hour periods before starting and 9 months after the weight reduction period. RESULTS: Adolescents gained (least-square mean +/- SE) 2.9 +/- 0.2 cm in height, lost 16.9 +/- 1.3 kg body weight (BW), 15.2 +/- 0.9 kg FM, and 1.8 +/- 0.5 kg fat-free mass (FFM) (p < 0.001). Basal metabolic rate, sleeping, sedentary, and daily EE were 8% to 14% lower 9 months after starting (p < 0.001) and still 6% to 12% lower after adjustment for FFM (p < 0.05). Energy cost of walking decreased by 22% (p < 0.001). The reduction in heart rate during sleep and sedentary activities (-10 to -13 beats/min), and walking (-20 to -25 beats/min) (p < 0.001) resulted from both the decrease in BW and physical training. DISCUSSION: A weight reduction program combining moderate energy restriction and physical training in severely obese adolescents resulted in great BW and FM losses and improvement of cardiovascular fitness but did not prevent the decline in EE even after adjustment for FFM.     

Impact of Sarcopenia and Obesity on Gait Speed After Total Knee Replacement

ObjectivesOlder adults with sarcopenic obesity have a higher risk of experiencing mobility difficulty. Additionally, sarcopenia and obesity are closely associated with knee osteoarthritis. This study investigated the associations of sarcopenia, obesity, and in combination of both with walking disability during postoperative rehabilitation in older adults with knee osteoarthritis who underwent total knee replacement.DesignA retrospective cohort study.Setting and ParticipantsFrom a rehabilitation center database, we retrospectively selected and investigated 482 older patients with knee osteoarthritis who had undergone total knee replacement and received postoperative rehabilitation.MethodsSarcopenia was identified in accordance with the diagnostic criteria established by the Asian Working Group for Sarcopenia and obesity was defined as body mass index ≥ 30 kg/m². Accordingly, patients were classified into four body composition groups, namely sarcopenic obese, sarcopenic, obese, and normal (reference group). After total knee replacement, all patients attended monthly follow-up admission during the postoperative rehabilitation. Gait speed was measured before surgery and monthly after total knee replacement. A gait speed cutoff of 1.0 m/s was used to identify postoperative walking disability. Kaplan–Meier curve analysis was performed to measure the probability of experiencing postoperative walking disability among the groups. Cox multivariate regression models were established to calculate the hazard ratios of postoperative walking disability.ResultsCompared with the reference group, the sarcopenic, obese, and sarcopenic obese groups appeared to have a higher probability of experiencing postoperative walking disability (all P < .001). The sarcopenic obese group were likely to have the highest risk of experiencing postoperative walking disability (adjusted hazard ratio = 3.89).Conclusions and ImplicationsSarcopenia or obesity alone may independently exert negative effects on postoperative gait speed. The participants with sarcopenic obesity were likely to have the highest risk of experiencing walking disability following total knee replacement. The findings may serve as a reference for clinicians developing rehabilitation strategies to optimize walking ability after total knee replacement, especially those preoperatively diagnosed as having sarcopenic obesity.     

Aerobic and anaerobic performance before and after a short-term body mass reduction program in obese subjects

The cardiovascular response to an aerobic cycloergometer exercise test (ACET, 15 min at 60 W, 60 rpm) and the maximally attainable muscle power output, assessed by a stair climbing test (SCT), were evaluated in 60 obese patients (41 females and 19 males; age: 18-68 yr; body mass index, BMI: 40.8+/-4.8 kg/m2) before and after a 3-week body mass reduction (BMR) program, entailing integrated energy-restricted diet (1200-1500 kcal/day), low-grade aerobic exercise conditioning and individual and/or group psychological therapy. The daily conditioning protocol (5 days/week) consisted of: 1) 30 min of indoor jogging and dynamic aerobic standing and floor exercises performed with arms and legs, under the guidance of a therapist; 2) 30 min of cycloergometer exercise at 60 W; and/or 3) 4-km outdoor leisure walking on flat terrain. Three weeks of BMR program induced a significant weight loss (-4.5 %; p<0.001), a reduction of systolic (-11+/-14 mmHg, -7.3%,p<0.001) and diastolic (-7+/-9 mmHg, -7.3%,p<0.001) resting arterial blood pressure, as well as a reduction of heart rate at rest (-18.6%,p<0.001), during ACET (-11.3%,p<0.001) and 5 min thereafter (-14.8%,p<0.001). The subjective rating of perceived exertion in terms of breathlessness and general fatigue during ACET, scored on a 0-100 visual analogic scale, was significantly reduced (p<0.001) after BMR program. A 11.2% decrease in SCT time (p<0.001) was also observed, corresponding to a 9.6% increase (p<0.001) in average muscle power (W) and 14.6% increase (p<0.001) in specific muscle power (W.kg(-1)). In conclusion, a combination of energy restricted diet, low intensity aerobic exercise and psychological counselling appears to significantly improve both aerobic and anaerobic performance in morbidly obese subjects. Different factors (ie, reduction of body mass, shift in the balance between parasympathetic and sympathetic activity, a weight-loss dependent shift toward a more favourable region of the muscle power-velocity curve, acquisition of a certain degree of motor skillfulness during the conditioning program, improvement of self-esteem and motivation) might be responsible, alone or in combination, for these short-term positive effects of BMR program.     

Assessment of energy expenditure associated with physical activities in free-living obese and nonobese adolescents

BACKGROUND: Information on activity patterns and the energy cost of activities is critically missing. OBJECTIVE: We measured the energy cost of and time devoted to various activities in obese and nonobese adolescents. DESIGN: Daily energy expenditure (DEE) and its main components were determined in 27 obese and 50 nonobese adolescents aged 12-16 y by using whole-body calorimetry with the same activity program and the heart rate-recording method in free-living conditions. RESULTS: In whole-body calorimetry, energy expenditures (EEs) during sleep and sedentary activities were 18.9% and 21.5%, respectively, higher in obese subjects than in nonobese subjects (P < 0.001), but not significantly different after adjustment for fat-free mass (FFM). EEs during walking and DEEs were significantly higher in obese than in nonobese subjects, both absolutely (71% and 33%, respectively) and after adjustment for body weight or FFM (16% and 11%, respectively). In free-living conditions, EEs associated with physical activities did not differ significantly between obese and nonobese subjects, but they were 51% lower in obese subjects after adjustment for body weight (P < 0.001). The obese adolescents spent more time in light physical activities but much less time in moderate activities and sports than did the nonobese subjects. The activity-related time equivalent corrected for sedentary EE (ARTE EE(2)) averaged 69 and 122 min/d in obese and nonobese subjects, respectively (P < 0.01). CONCLUSION: Physical activity is low in obese subjects and can be assessed satisfactorily in both obese and nonobese adolescents by using ARTE EE(2) when DEE and the basal metabolic rate are known.     

我国成人步行和慢跑基本特征与代谢当量初探

目的探索我国成人步行、慢跑的速度、步频和代谢当量等基本特点。方法 39名23～64岁健康成人在室外100米塑胶跑道上按拟合后的步频,先后进行每分钟90步、120步的步行和每分钟150步、180步跑步,人工记录步数、距离。其中24人在400米塑胶跑道上先后按每分钟100步步行5 min和每分钟160步慢跑3分钟,以K4b2气体代谢遥测仪测量运动耗能,人工记时和测距。结果每分钟100、120步[平均(4.2±0.4)km/h、(5.2±0.4)km/h]接近样本人群(23～64岁)中速走、快走的自然步频,每分钟160步接近慢跑的自然步频[平均(8.5±1.4)km/h]。其代谢当量2.5、5.5MET,均显著低于美国《身体活动概要》相应推荐值,但显著相关(r=0.723、0.791;P0.01)。结论样本人群步行、慢跑的基本特点与国外数据基本一致。     

The effects of a 20-week exercise training program on resting metabolic rate in previously sedentary, moderately obese women

The present study was designed to investigate the effects of exercise training on resting metabolic rate (RMR) in moderately obese women. It was hypothesized that exercise training would increase resting metabolic rate. Nineteen previously sedentary, moderately obese women (age = 38.0 +/- 0.9 years, percent body fat = 37.5 +/- 0.8) trained for 20 weeks using either resistance training (RT) or a combination of resistance training and walking (RT/W). The high intensity resistance-training program was designed to increase strength and fat-free mass and the walking program to increase aerobic capacity. There was also a non-exercising control group (C) of 9 subjects in this study. Fat-free mass was significantly increased in both the RT (+1.90 kg) and RT/W (+1.90 kg) groups as a result of the training program. No group showed significant changes in fat mass or relative body fat from pre- to post-training. Aerobic capacity was slightly, though significantly, increased in the RT/W group only. The RT group showed a significant increase (+44 kcal x day(-1)), while the RT/W group showed a significant decrease (-53 kcal x day(-1)) in resting metabolic rate post-training. RT can potentiate an increase in RMR through an increase in fat-free mass, and the decrease in RMR in the RT/W group may have been a result of heat acclimation from the walk training.     

Dual-energy x-ray absorptiometry for total-body and regional bone-mineral and soft-tissue composition

Bone mineral density (BMD) and soft-tissue composition of the total body and major subregions were measured with dual-energy x-ray absorptiometry (DEXA). Total body scans were made in 12 young adults (6 male, 6 female) on five occasions at both a medium speed (20 min) and a fast speed (10 min). There were no significant differences in mean results or in precision errors between the two speeds. The precision errors (1 SD) for total body BMD, percent fat in soft tissue (% Fat), fat mass, and lean tissue mass were less than 0.01 g/cm2, 1.4%, 1.0 kg, and 0.8 kg, respectively. These results corresponded to a relative error of 0.8% for total body BMD and 1.5% for lean body mass. Regional BMD and soft-tissue values (arms, legs, trunk) were determined with slightly higher precision errors. Skeletal mineral was 5.8 +/- 0.5% of lean tissue mass (r = 0.96, p less than 0.001). DEXA provides precise composition analysis with a low radiation exposure (less than 0.1 microGy).     

Validation of ActiReg to measure physical activity and energy expenditure against doubly labelled water in obese persons

ActiReg is an instrument that uses combined recordings of body position and motion to calculate energy expenditure (EE) and physical activity (PA). The aim of the study was to compare mean total energy expenditure (TEE) measured by ActiReg and doubly labelled water (DLW) in obese subjects. TEE was measured by the DLW method during a period of 14 d in fifty obese men and women with metabolic risk factors. During the same period ActiReg recordings were obtained for 7 d. RMR was measured by indirect calorimetry and also estimated by standardized equations. Because EE may be disproportionately increased in obese subjects during weight-bearing activities, we established a new set of physical activity ratios (PAR). These ratios were based on oxygen uptake measurements during treadmill walking. The mean TEE according to the DLW was 13.94 (sd 2.47) MJ/d. Mean TEE calculated from the ActiReg data and measured RMR was 13.39 (sd 2.26) MJ/d, an underestimation of 0.55 MJ (95 % CI 0.13, 0.98; P = 0.012) or 3.9 %. RMR derived from standard equations based on weight, age and sex were overestimated while the RMR based on fat-free mass values in addition was underestimated. Despite slight underestimation ActiReg may be used to measure TEE in obese subjects on two premises: RMR should be measured, and the increased EE during weight-bearing activities in obese subjects should be considered.     

Effects of weekly administration of pegylated recombinant human OB protein on appetite profile and energy metabolism in obese men

BACKGROUND: Results of leptin administration in mice, rats, and humans provide a rationale for therapeutic augmentation of circulating leptin (OB protein) concentrations in obese humans; this may reduce food intake, increase metabolic rate, and lower body mass. OBJECTIVE: We assessed the effects of weekly subcutaneous pegylated polyethylene glycol (PEG)-OB protein administration on appetite and energy metabolism in obese men. DESIGN: We performed a randomized, double-blind, placebo-controlled trial in 30 obese men [body mass index (in kg/m(2)): 34.2 +/- 3.6; age: 44.7 +/- 7 y]. Subjects received 20 mg PEG-OB protein/wk for 12 wk while limiting their energy intake to 2.1 MJ/d. RESULTS: During treatment, appetite and hunger before breakfast decreased and remained lower in the PEG-OB-protein group, whereas they increased and remained higher in the placebo group (P < 0.0001). During treatment, hunger decreased in the PEG-OB-protein group (P < 0.05) and cognitive restraint increased in the placebo group (P < 0.0001). Neither appetite nor food intake changed significantly during the ad libitum evening meal. Under energy balance conditions in the respiration chamber, appetite at the end of treatment was not significantly different from baseline despite similar, significant reductions in 24-h energy intake, energy expenditure, sleeping metabolic rate, body mass, fat mass, and fat-free mass (P < 0.01 for all) in both groups. CONCLUSION: Treatment with PEG-OB protein modified subjective appetite at a dosage that produced no changes in body composition, energy expenditure, or body mass loss relative to placebo treatment, suggesting that PEG-OB protein has central rather than peripheral biological activity in obese men.     

Association of energy intake and macronutrient composition with overweight and obesity in malay women from klang valley

This cross-sectional study investigates the association between energy intake and macronutrient composition of the diet with overweight and obesity among Malaysian women. One hundred and fifteen adult Malay women aged 20 to 59 years (mean age 37.2±7.6 years) were interviewed. Dietary intake was assessed using the food history method. Body weight status was assessed using weight, height, waist circumference and fat percentage measurements. When energy intake was assessed for accuracy, only 41% of the subjects (n=47) were normal energy reporters. Among the normal energy reporters, 55% were of normal weight whereas 32% and 13% were overweight and obese. Mean energy intake for normal weight, overweight and obese subjects was 1685±199 kcal/day, 1810±166 kcal/day and 2119±222 kcal/day, respectively. Energy intake increased with body mass index (BMI) category. Among the overweight and obese, energy intake was respectively higher by 125 kcal/day and 434 kcal/day as compared to their normal weight counterparts (p< 0.001). There was also a significant, moderate and positive correlation between energy intake and BMI (r=0.635), waist circumference (r=0.545), and body fat percentage (r=0.534). When macronutrient composition of diet was analysed (% energy and g/1000 kcal), there was no significant difference in carbohydrate, protein or fat intake between the obese, overweight and normal weight subjects. There was also no significant correlation between macronutrient composition of the diet and body weight status. Based on these findings, we conclude that the subjects' body weight status is likely to be influenced by energy intake rather than the macronutrient composition of the diet.     

肥胖儿童青少年每日步数与减脂效果的剂量效应关系

目的 探究肥胖儿童青少年每日不同步数与减脂效果间是否存在非线性关系和阈值效应,以期为肥胖儿童青少年的运动减脂提供科学精准的理论依据。方法 2021年7—8月,在深圳减肥达人训练营招募48名10～17岁肥胖儿童青少年进行4周封闭式运动训练,使用ActiGraph GT3X+监控每日步数,通过干预前后身体成分指标的变化评价减脂效果。干预前后指标的比较使用配对样本t检验;每日步数与减脂效果间的剂量-效应关系使用线性回归及分段回归分析,非线性关系的分析使用限制性立方样条(RCS)分析。结果 干预后体脂肪量(27.50±7.33)kg、体脂百分比(36.17±5.59)%、瘦体重(47.55±6.48)kg、骨骼肌量(26.14±3.84)kg较干预前[(31.97±7.82)kg,(39.06±5.12)%,(49.08±6.93)kg,(27.08±4.15)kg]均下降(t值分别为21.04,13.32,7.65,8.35,P值均<0.05),每日步数与以上指标的变化量间存在非线性剂量-效应关系(P值均<0.05);分段回归结果显示,校正年龄、性别和基线BMI后,每日步数每增加...     

Effect of daily energy intake and amount of walking on body weight reduction and its maintenance]

The relationship of daily energy intake and the amount of walking performed, based on pedometer readings, for effective body weight reduction were studied based on results of a weight reduction program at the Aichi Prefectural Center of Health Care from 1983 to 1990. In addition, a follow-up study based on a mailed questionnaire was performed, to further determine the relationship to maintenance of body weight reduction of energy intake and amount of walking after the conclusion of program. The subjects were two-hundred and forty middle-aged obese women who were placed on a 5-month weight reduction program consisting of diet (1500 kcal/day) and exercise (10000 walk steps/day). At the end of the program, the mean energy intake and the mean number of steps per day had reached target levels and the mean body weight reduction was 4.2 kg. The relationship of energy intake, and the number of steps walked at the end of program to the amount of reduction in body weight during the program was analyzed by multiple regression analysis, and the amount of walking expressed in the number of steps necessary for weight reduction were calculated for various energy intakes. A follow-up study was performed in 1988, with sixty-six women responding to the mailed questionnaire. Since the end of the program, body weight increase of 1.1 kg occurred, but body weight was still lower than initially. Although mean energy intake increased after the program, a level about 200 kcal less than at the beginning of the program was being maintained, so the effect of diet recommendation in the program appeared to be retained.(ABSTRACT TRUNCATED AT 250 WORDS)     

Efficiency of walking and stepping: relationship to body fatness

OBJECTIVE: To determine energetic efficiency of walking and stepping in a heterogeneous normal adult population and its association with body fatness and to assess within- and between-individual variations. RESEARCH METHODS AND PROCEDURES: Using a combination of a whole-room indirect calorimeter and a large precision force platform, we simultaneously measured minute-by-minute energy expenditure (EE) and mechanical work during walking and stepping in healthy adult men (n = 60) and women (n = 85). Efficiency was calculated as a ratio (percentage) of mechanical work and EE of activity. Efficiency of walking and stepping performed at various intensities was compared for reproducibility within the same day (morning and afternoon) and correlated with a subject's characteristics. RESULTS: The efficiency of walking was negatively correlated with body fatness in both men and women at 0.9 to 1.2 m/s but positively correlated with body fatness in men and not correlated in women at the slowest speed tested (0.6 m/s). Efficiency of walking and stepping of various intensities was reproducible during the same day. Compared at similar EE levels, walking was more efficient than stepping (26% to 27% vs. 18% to 22%, p < 0.01). Women were significantly (p < 0.01) more efficient than men during stepping. Age, sex, body mass, fat-free mass, fitness (maximal oxygen uptake), height, and speed variations contributed to the between-subject differences in efficiency. DISCUSSION: Obese individuals were less efficient than lean individuals during normal-speed walking. Significant interindividual variations in efficiency of walking and stepping may be attributed to habituation and physical characteristics such as age, sex, and fitness level.     

The effects of different percentages of dietary fat intake, exercise, and calorie restriction on body composition and body weight in obese females

PURPOSE. The goal of this study was to determine the effect of varying the amount of dietary fat, while holding calories at 1,200 kcals/day, on body weight and percent body fat in 35 obese women. DESIGN. A pretest, midtest, posttest experimental design was employed, and subjects were randomly divided into one of four dietary fat groups, with 10%, 20%, 30%, or 40% of caloric intake as dietary fat. INTERVENTION. Subjects consumed 1,200 kcals/day and a specified percentage of total energy as fat, depending on their dietary group. Protein was held constant at 20%. All subjects engaged in a five day/week walking program. SETTING. Participants were recruited from the general community using newspaper advertisements. SUBJECTS. Thirty-five obese women 25 to 45 years of age (means=38 +/- 4.97) served as subjects. All were at least 20% above ideal weight and 30% to 52% body fat. MEASURES. Percent body fat, body weight, and anthropomorphic measurements were taken at baseline, six and 12 weeks. Dietary intake was recorded daily by each subject, and exercise walking logs were maintained by each participant. RESULTS. All subjects lost body weight and body fat; however, there were no significant differences in the rate or amount of body weight or percent body fat lost across the four groups during the intervention. CONCLUSIONS. It appears that during calorie restriction and exercise for 12 weeks, percent of calories derived from dietary fats does not influence loss of body weight or percent body fat in adult obese women.     

Determinants of childhood overweight and obesity in China

In order to investigate the determinants of childhood overweight and obesity in China, the prevalence of overweight (including obesity) was compared according to different dietary and physical activity patterns and parental body weight status. A total of 6826 children aged 7-17 years from the 2002 China National Nutrition and Health Survey were included in the study. Information for dietary intake was collected using three consecutive 24-h recalls by trained interviewers. The amounts of cooking oil and condiments consumed were weighed. An interview-administered 1-year physical activity questionnaire was used to collect physical activity information. The results showed that the heavier the parental bodyweight, the higher the overweight prevalence in children. The prevalence ratio increased if parent(s) were overweight and/or obese, up to 12.2 if both parents were obese. Overweight children consumed significantly more dietary energy, protein and fat, but less carbohydrate than their normal weight counterparts. On average, overweight children spent 0.5 h less on moderate/vigorous activities and 2.3 h more on low intensity activities per week. The following prevalence ratios were statistically significant: walking to and from school (0.6); moderate/vigorous activities > or =45 min/d (0.8); low intensity physical activities >2 h/d (1.3); the consumption of > or =25 g/d cooking oil (1.4); > or =200 g/d meat and meat products consumption (1.5); > or =100g/d dairy products (1.8). After adjustment for parental body weight status and socioeconomic status, only cooking oil consumption and walking to and from school remained significantly related to child overweight. In conclusion, parental weight status is an import-ant determinant. Fat intake, low intensity activities and active transport to/from school may be suitable entry points for overweight prevention among Chinese school children.     

Body fat distribution and energy metabolism in obese men and women.

Upper body obesity seems to be associated with a better prognosis for weight loss than does lower body obesity. However, the impact of body fat distribution on energy metabolism is not clear.

One hundred fifteen non-diabetic obese Caucasians (64 males and 51 females) and 108 Caucasian lean controls (82 males and 26 females) were studied.

Body composition was assessed by hydrodensitometry and body fat distribution was estimated by the waist-to-thigh circumference ratio (W/T). Values of 24-hour energy expenditure (24h-EE), basal metabolic rate (BMR), sleeping metabolic rate (SMR) and respiratory quotient (RQ) were measured in a respiration chamber.

BMR, adjusted for differences in fat-free mass, fat mass, age and sex, correlated with W/T in obese males (r = 0.40; p < 0.01), but not in obese females. Obese male subjects with upper body obesity had BMR significantly higher than those with lower body obesity (2189 +/? 268 vs 1974 +/? 141 kcal/day; p < 0.01), independently of differences in fat-free mass, fat mass and age. No correlations were found between W/T and adjusted 24h-EE, SMR or RQ in all examined groups.

These findings indicate that in obese males, upper body obesity is associated with increased metabolic rate, possibly related to higher levels of lipid turnover in visceral fat.