A meta-analysis of the effects of exercise and/or dietary restriction on resting metabolic rate

Assessment of Changes in Body Composition During the First Postoperative Year After Bariatric Surgery

BACKGROUND

The potential effect of bariatric surgery on weight reduction and improvement of associated comorbidities is known, but the ratio obtained between the components of body weight, including lean body mass, body fat mass, and bone mass, is still not determined. This study aims to verify the changes in body composition during the first year after bariatric surgery.

METHODS

We conducted a prospective observational cohort study. Fifty patients who underwent bariatric surgery and maintained follow-ups were selected. Patients were assessed preoperatively and postoperatively for periods of 1, 3, 6, and 12 months using tetrapolar bioelectrical impedance analysis and laboratory testing of lipids and serum albumin levels. Data were statistically analyzed.

RESULTS

Statistically significant differences (p < 0.001) were obtained between the preoperative and 12-month evaluation respectively, for body mass index (BMI) (45.8 ± 7.5 to 30.0 ± 4.8 kg/m²), FM (64.7 ± 15.5 to 30.6 ± 9.8 kg), PFM (51.6 ± 4.17 to 37.3 ± 7.6%), and total cholesterol levels (197.1 ± 49.8 to 169.8 ± 31.0 mg/dL). The decrease in PFM shows a better proportion between the body components. PFM showed significantly higher decrease in males than in females (p = 0.012). Lean body mass (p = 0.000) reduction was highest for patients operated by the Unified Health System (SUS, Government of Brazil) probably because of its few financial resources to maintain postoperative care.

CONCLUSION

The change in body composition of patients who underwent Roux-en-Y gastric bypass was statistically significant for all variables examined during the first year postoperatively. This shows the effectiveness of the surgical procedure and clinical protocol set, which tends to favor a better health prognosis and weight maintenance in the long term.

One-year caloric restriction and 12-week exercise training intervention in obese adults with type 2 diabetes: emphasis on metabolic control and resting metabolic rate

PURPOSE

The effect of combined lifestyle interventions (LSI) including dietary and physical activity on metabolic health, energy metabolism and VO₂max in diabetic patients has provided mixed results. We evaluated the impact of 1-year caloric restriction (CR), and 12-week supervised structured exercise training (SSET) on metabolic health, RMR and VO₂max in obese adults with type 2 diabetes.

METHODS

After 1-month education for LSI, 33 participants had anthropometric, biochemical and metabolic assessments. They then started CR based on RMR, and 3-month SSET during the months 1-3 (Early-SSET) or 4-6 (Late-SSET). Reassessments were planned after 3, 6 and 12 months. Using a per-protocol analysis, we evaluated parameter changes from baseline and their associations for the 23 participants (11 Early-SSET, 12 Late-SSET) who completed the study. RMR was adjusted (adjRMR) for age, sex, fat-free mass (FFM) and fat mass (FM).

RESULTS

Compared with baseline, after 6 months we found significant increases in VO₂max (+ 14%) and HDL-cholesterol (+ 13%), and reduction in body mass index (- 3%), FM (- 8%) and glycated hemoglobin (HbA1c, - 7%). Training-related caloric expenditure negatively correlated with changes in body weight (p < 0.001), FM (p < 0.001) and HbA1c (p = 0.006). These results were confirmed at the 12-month follow-up. Pooling together all follow-up data, adjRMR changes correlated with changes in glycemia (r = 0.29, p = 0.02), total-cholesterol (r = 0.29, p = 0.02) and VO₂max (r = - 0.26,p = 0.02). No significant differences emerged between the Early- and Late-SSET groups.

CONCLUSIONS

Combined intervention with SSET and CR improved metabolic control. Changes in metabolic health and fitness correlated with changes of adjRMR, which was reduced improving fitness, glycemia and cholesterolemia.

CLINICAL TRIAL REGISTRY

Trial registration number: NCT03785379. URL of registration: http://clinicaltrials.gov .

Physical Activity Energy Expenditure and Total Daily Energy Expenditure in Successful Weight Loss Maintainers

OBJECTIVE

The objective of this study was to compare physical activity energy expenditure (PAEE) and total daily energy expenditure (TDEE) in successful weight loss maintainers (WLM) with normal weight controls (NC) and controls with overweight/obesity (OC).

METHODS

Participants were recruited in three groups: WLM (n = 25, BMI 24.1 ± 2.3 kg/m² ; maintaining ≥ 13.6-kg weight loss for ≥ 1 year), NC (n = 27, BMI 23.0 ± 2.0 kg/m² ; similar to current BMI of WLM), and OC (n = 28, BMI 34.3 ± 4.8 kg/m² ; similar to pre-weight loss BMI of WLM). TDEE was measured using the doubly labeled water method. Resting energy expenditure (REE) was measured using indirect calorimetry. PAEE was calculated as (TDEE - [0.1 × TDEE] - REE).

RESULTS

PAEE in WLM (812 ± 268 kcal/d, mean ± SD) was significantly higher compared with that in both NC (621 ± 285 kcal/d, P < 0.01) and OC (637 ± 271 kcal/d, P = 0.02). As a result, TDEE in WLM (2,495 ± 366 kcal/d) was higher compared with that in NC (2,195 ± 521 kcal/d, P = 0.01) but was not significantly different from that in OC (2,573 ± 391 kcal/d).

CONCLUSIONS

The high levels of PAEE and TDEE observed in individuals maintaining a substantial weight loss (-26.2 ± 9.8 kg maintained for 9.0 ± 10.2 years) suggest that this group relies on high levels of energy expended in physical activity to remain in energy balance (and avoid weight regain) at a reduced body weight.

Effects of breathing exercises on resting metabolic rate and maximal oxygen uptake

[Purpose] The aim of the present study is to examine effects of diaphragm breathing exercise and feedback breathing exercise on maximal oxygen uptake and resting metabolic rate. [Participants and Methods] Thirty-eight healthy participants were randomly assigned to two groups; the diaphragm breathing exercise group and the feedback breathing exercise group. The diaphragm breathing exercise group was asked to perform diaphragm respiration, and the feedback breathing exercise group was asked to breathe with feedback breathing device. Maximal oxygen uptake and resting metabolic rate were measured before and after two breathing exercises. [Results] Significant difference was found in maximal oxygen uptake before and after two breathing exercises. There was also significant difference in resting metabolic rate before and after diaphragm breathing exercise. However, significant difference was not found in resting metabolic rate before and after feedback breathing exercise. There were not significant between-group differences in both maximal oxygen uptake and resting metabolic rate. [Conclusion] Diaphragm breathing exercise and feedback breathing exercise could influence maximal oxygen uptake. Diaphragm breathing exercise could influence resting metabolic rate, but feedback breathing exercise could not.

Energy compensation in response to aerobic exercise training in overweight adults

Weight loss from exercise is often less than expected. Putative compensatory mechanisms may limit exercise-induced reductions in body fat and might be proportional to exercise energy expenditure (ExEE). This study was conducted to determine compensation for (the difference between accumulated exercise energy expenditure and changes in body tissue energy stores) and compensatory responses to 1,500 or 3,000 kcal/wk of ExEE. Overweight-to-obese ( n = 36) sedentary men and women were randomized to groups expending 300 or 600 kcal/exercise session, 5 days/wk, for 12 wk. Fourteen participants in the 300-kcal group and 15 in the 600-kcal group completed the study. The primary outcome was energy compensation assessed through changes in body tissue energy stores. Secondary outcomes were putative compensatory responses of resting metabolic rate, food reinforcement, dietary intake, and serum acylated ghrelin and glucagon-like peptide-1. All measures were determined pre- and posttraining. The 3,000 kcal/wk group decreased ( P < 0.01) percentage and kilograms of body fat, while the 1,500 kcal/wk group did not. The 1,500 and 3,000 kcal/wk groups compensated for 943 (-164 to 2,050) and 1,007 (32 to 1,982) kcal/wk (mean, 95% CI, P ≥ 0.93), or 62.9% and 33.6% of ExEE, respectively. Resting metabolic rate and energy intake did not change. Food reinforcement and glucagon-like peptide-1 decreased ( P < 0.02), whereas acylated ghrelin increased ( P ≤ 0.02). Compensation is not proportional to ExEE. Similar energy compensation occurred in response to1,500 and 3,000 kcal/wk of ExEE. ExEE of 3,000 kcal/wk is sufficient to exceed compensatory responses and reduce fat mass.

The associations of resting metabolic rate with chronic conditions and weight loss

The aim of this study was to examine the associations between baseline and changes in resting metabolic rate (RMR) with chronic condition(s) and weight loss (WL). Sex stratified analysis was undertaken on 393 adults from the Wharton Weight Management Clinics. The association between baseline RMR and WL was examined adjusting for age, BMI, ethnicity and treatment time. The association between changes in RMR (ΔRMR) and WL was also examined adjusting for baseline RMR and above covariates. Models were further adjusted for high glucose, triglycerides, blood pressure, low-density lipoprotein (LDL) and low high-density lipoprotein (HDL). While men (6.0 ± 8.6 kg) and women (5.6 ± 8.3 kg) had significant WL throughout the intervention, their measured decreases in RMR (-48 ± 322 kcal and -5 ± 322 kcal, respectively) were non-significant (P > 0.05). Individuals with a high blood pressure had a higher baseline RMR and women with a high LDL had a lower baseline RMR than those without the chronic condition (P < 0.05). Regardless of sex, WL was not significantly associated with baseline RMR or ΔRMR (P > 0.05) in both models. Participants with a low baseline RMR do not appear to be at a disadvantage for WL. Further, WL can occur without decreases in RMR in populations with high levels of obesity and obesity-related comorbidities.

Why do individuals not lose more weight from an exercise intervention at a defined dose? An energy balance analysis

Weight loss resulting from an exercise intervention tends to be lower than predicted. Modest weight loss can arise from an increase in energy intake, physiological reductions in resting energy expenditure, an increase in lean tissue or a decrease in non-exercise activity. Lower than expected, weight loss could also arise from weak and invalidated assumptions within predictive models. To investigate these causes, we systematically reviewed studies that monitored compliance to exercise prescriptions and measured exercise-induced change in body composition. Changed body energy stores were calculated to determine the deficit between total daily energy intake and energy expenditures. This information combined with available measurements was used to critically evaluate explanations for low exercise-induced weight loss. We conclude that the small magnitude of weight loss observed from the majority of evaluated exercise interventions is primarily due to low doses of prescribed exercise energy expenditures compounded by a concomitant increase in caloric intake.

Physical activity plays an important role in body weight regulation

Emerging literature highlights the need to incorporate physical activity into every strategy intended to prevent weight gain as well as to maintain weight loss over time. Furthermore, physical activity should be part of any plan to lose weight. The stimulus of exercise provides valuable metabolic adaptations that improve energy and macronutrient balance regulation. A tight coupling between energy intake and energy expenditure has been documented at high levels of physical exercise, suggesting that exercise may improve appetite control. The regular practice of physical activity has also been reported to reduce the risk of stress-induced weight gain. A more personalized approach is recommended when planning exercise programs in a clinical weight loss setting in order to limit the compensatory changes associated to exercise-induced weight loss. With modern environment promoting overeating and sedentary behavior, there is an urgent need for a concerted action including legislative measures to promote healthy active living in order to curb the current epidemic of chronic diseases.

Interindividual variations in resting metabolic rate during weight loss in obese postmenopausal women A pilot study

The objective of the study was to examine if decreases in resting metabolic rate (RMR) take place early in the weight loss process and if they remain throughout the duration of the weight loss intervention. Twenty obese postmenopausal women (61.8 +/- 5.9 years) participated in a 15-week weight loss program. After the fifth week, subjects were characterized as having an increased (>5%) or a decreased (<5%) RMR based on baseline values. Afterward, they were followed for an additional 10 weeks. Outcome measures were as follows: fat mass ([FM] total, trunk), lean body mass (total, trunk), RMR, resting heart rate (RHR), and physical activity level. After 5 weeks, significant decreases were observed for lean body mass, FM, and RHR (P < .05), whereas no overall changes in physical activity level and RMR were observed. However, on an individual basis, large variations in RMR were observed (ranging from -320 to +330 kcal/d). Analyses showed that subjects characterized as either having an increased or a decreased RMR after the fifth week maintained these adaptations at the end of intervention. Finally, subjects displaying a decreased RMR during weight loss had a significantly higher RMR and lower FM accumulations at baseline (total and trunk) compared with those with an increased RMR. Interindividual variations in RMR took place early in the weight loss process and were maintained over the duration of the weight loss program in our cohort of obese postmenopausal women. Baseline RMR, changes in RHR, and FM accumulations (total and trunk) seem to be important factors to consider when studying the effects of weight loss on RMR.

Dietary fat oxidation as a function of body fat

PURPOSE OF REVIEW

Is trafficking of dietary fat involved in the development of obesity?

RECENT FINDINGS

Studies on energy expenditure and substrate utilization during overfeeding, studies on individual differences in substrate utilization between individuals fed at energy balance, and differences in responses in energy expenditure and substrate utilization in individuals after weight reduction, illustrate that the capacity of fat oxidation is a potential determinant for the development of obesity.

SUMMARY

The ability to store dietary fat seems to be involved in the susceptibility to gain weight during a positive energy balance. Obese individuals show less oxidation and more storage of dietary fat as compared with the lean phenotype. Differences in fuel trafficking make individuals prone to overeating in the current obesogenic environment with a high availability of energy-dense fatty foods. It is difficult to get rid of excess body fat as energy requirement for weight maintenance after weight reduction is lower than predicted from the new body composition reached and thus, there is a high risk for weight regain.

Physical activity as determinant of daily energy expenditure

Inter-individual variation in energy expenditure is mainly a function of differences in body size and physical activity. Intra-individually, the energy expenditure associated with physical activity, i.e. muscular contractions to perform body postures and -movements, is the most variable component of total energy expenditure. Determinants of activity associated energy expenditure (AEE), as derived from observational and intervention studies are presented. Twin studies showed that most of the between subject variation in AEE is explained by genetic factors. AEE of subjects in the confined environment of a respiration chamber was on average halve the value as observed in the same subjects in free-living conditions with doubly labeled water. In young adults, non-training activity was not affected by exercise training. However, in elderly subjects, exercise training induced an equivalent compensatory decline in non-training activity. Similarly, AEE was reduced during energy restriction and in patients with chronic disease increasing resting energy expenditure. Studies with exercise training showed the reduction is difficult to overcome.

Metabolismo de repouso de mulheres pós-menopausadas submetidas a programa de treinamento com pesos (hipertrofia)

O estudo objetivou avaliar o gasto energético de repouso (GER) de mulheres pós-menopausadas submetidas a programa de treinamento com pesos. Foram estudadas 30 mulheres (FSH > 40mIU/mL) entre 45 e 70 anos, separadas em dois grupos (GT: treinamento, n = 15 e GC: controle, n = 15). Calculou-se o índice de massa corporal (kg/m²) e por meio da impedância bioelétrica (BIA) determinaram-se o percentual de gordura corporal e a massa muscular. O GER foi obtido por meio da calorimetria indireta (O2 e CO2 respiratórios) e calculado pela equação de Weir. A mensuração ocorreu após 12 horas de jejum, durante 30 minutos sob temperatura e umidade controladas. O GT participou do programa de treinamento com pesos durante 16 semanas, na freqüência de três vezes por semana. Os dados analisados pelos testes t de Student, Mann-Whitney e ANOVA (p < 0,05) demonstraram que o GT teve a massa corporal aumentada na média de 1,8kg, a massa muscular em 2,0kg e o GER apresentou elevação de 8,4% em relação ao GC. Em conclusão, o treinamento com pesos aumentou a massa muscular e o GER. Recomenda-se, portanto, esse tipo de exercício como parte de conduta para reverter perdas muscular e metabólica decorrentes do envelhecimento e/ou da menopausa.

Avoidance of unhealthy fattening: A longstanding proposal

Diverse customary patterns of eating, drinking or movement are hypothesised to be effective in weight control based on laboratory experiments or theoretical calculations, in some cases supported by ecologically valid evidence. This method is applicable to healthy members of the public and to patients at high risk of and from obesity such as those having type-2 diabetes or chronic arthritis. Weight-reducing behaviour not adequately identified in current best practice educational messages includes: integration of exercise into desk-based employment; uses of stairs; uncompensated vigorous activity or reduction in amount eaten at a meal; protein level and carbohydrate timing in meals; having a "snack". This paper presents the scientific parts of a request for funds to integrate a suite of research methods based on theoretical models that can be applied to identify further, culturally and locally specific eating customs that avoid overweight and reduce obesity and can be iterated in a continuous (re)development of evidence-based expert advice and self-care practices in health and chronic disease.

Heart rate response to therapeutic riding in children with cerebral palsy: an exploratory study

PURPOSE

The study was designed to document the heart rate response to therapeutic riding in children with cerebral palsy having mild-to-severe disability.

METHODS

Participants consisted of eight youth riders with cerebral palsy, divided into two groups: ambulatory and wheelchair dependent. The riders received continuous digital heart rate monitoring during 10 weekly 20-minute therapeutic horseback riding sessions.

RESULTS

The averaged resting, median, and peak heart rate values, as well as the peak percentage heart rate reserve values, were significantly higher in the wheelchair-dependent group.

CONCLUSIONS

The youth with severe disability (The Gross Motor Function Classification System level IV) who were wheelchair dependent demonstrated higher heart rate values during therapeutic riding than their ambulatory counterparts. In view of these higher heart rate values, further studies are needed to address the role of monitoring heart rate response during therapeutic riding.

Assessment of a high-throughput screening methodology for the measurement of purified UCP1 uncoupling activity

Three mitochondrial uncoupling proteins (UCP1, 2, 3) have been described. The proton transport activity of UCP1 triggers mitochondrial uncoupling and thermogenesis but the roles of UCP2 and UCP3 remain debated. Accordingly, compounds able to finely control the proton permeability of the mitochondrial inner membrane where and when needed may have enormous practical consequences. Using purified hamster brown adipose tissue UCP1 reconstituted in liposomes, we describe herein a robust assay allowing the measurement of this artificial membrane conductance to protons in a format compatible with high-throughput screening. The assay was initially developed with a known chemical protonophore in an aproteic system. Then, using the proteolipid reconstituted UCP1 preparation, we assessed the assay with known modulators of UCP1, particularly retinoic acid and guanosine 5'-triphosphate. The system was developed for a 96-well plate format. We then exemplified its use by generating primary data on a set of compounds screened in this system. These primary data will open new routes for the search of candidate compounds that will help biochemical studies on UCPs.

Physical activity and human energy expenditure

PURPOSE OF REVIEW

This is a review on the measurement of physical activity under daily life conditions. The focus is on the doubly labelled water method and accelerometry. Doubly labelled water is a gold standard and the reference for the validation of field methods to assess physical activity. Accelerometry is the most objective and precise technique to assess activity patterns in terms of frequency, duration and intensity. Applications of the two techniques are illustrated with the limits of physical activity and energy expenditure and with activity intensity as a determinant of the physical activity level.

RECENT FINDINGS

The upper limit of the physical activity index (total energy expenditure as a multiple of basal metabolic rate) of 2.5, as derived from cross-sectional data, is confirmed by training intervention studies. Exercise training, in which total energy expenditure was measured before and at the end of the training programme, showed no increase in physical activity index when training was combined with an energy restricted diet and in elderly subjects. In children, the distribution of time spent at activities with low and high intensity determines the physical activity index while in adults moderate-intensity activities are the main determinant.

SUMMARY

In adults, within the normal physical activity index range, the distribution of time spent at activities with low and moderate intensity determines the physical activity level. High-intensity activity does not have much impact on daily energy expenditure. High-intensity activity is not required to increase the activity energy expenditure.

Obesity: the integrated roles of environment and genetics

Obesity represents one of the most serious global health issues with approximately 310 million people presently affected. It develops because of a mismatch between energy intake and expenditure that results from behavior (feeding behavior and time spent active) and physiology (resting metabolism and expenditure when active). Both of these traits are affected by environmental and genetic factors. The dramatic increase in the numbers of obese people in Western societies reflects mostly changing environmental factors and is linked to reduced activity and perhaps also increased food intake. However, in all societies and subpopulations, there are both obese and nonobese subjects. These differences are primarily a consequence of genetic factors as is revealed by the high heritability for body mass index. Most researchers agree that energy balance and, hence, body weight are regulated phenomena. There is some disagreement about exactly how this regulation occurs. However, a common model is the "lipostatic" regulation system, whereby our energy stores generate signals that are compared with targets encoded in the brain, and differences between these drive our food intake levels, activity patterns, and resting and active metabolisms. Considerable advances were made in the last decade in understanding the molecular basis of this lipostatic system. Some obese people have high body weight because they have broken lipostats, but these are a rare minority. This suggests that for the majority of obese people, the lipostat is set at an inappropriately high level. When combined with exposure to an environment where there is ready availability of food at low energy costs to obtain it, obesity develops. The evolutionary background to how such a system might have evolved involves the evolution of social behavior, the harnessing of fire, and the development of weapons that effectively freed humans from the risks of predation. The lipostatic model not only explains why some people become obese whereas others do not, but also allows us to understand why energy-controlled diets do not work. Drug-based solutions to the obesity problem that work with the lipostat, rather than against it, are presently under development and will probably be in regular use within 5-10 y. However, several lines of evidence including genetic mapping studies of quantitative trait loci associated with obesity suggest that our present understanding of the regulatory system is still rudimentary. In particular, we know nothing about how the target body weight in the brain is encoded. As our understanding in this field advances, new drug targets are likely to emerge and allow us to treat this crippling disorder.

Weight management in women

With 61% of the American population overweight or obese, the need for treatment far exceeds the capacity of the health care system to provide care on an individual basis. Moreover, the most effective method for the delivery of treatment, and the best ways to induce and sustain client adherence to such a program, remain elusive. Obesity stands in the ignominious position of being the only epidemic in the latter decades of the twentieth century and into the new millennium that nurses--clinicians, academicians, and investigators alike seem to have virtually ignored. There are few past or present clinical descriptions, curriculum examples, or research results that have been presented or published by nurses that demonstrate the discipline's recognition of and commitment to this pervasive health problem. With the ever-increasing prevalence of obesity and obesity-related diseases, the burgeoning expansion of health care delivery in outpatient care, and the growing emphasis on health promotion, it is imperative that nurses in all roles give their long overdue and concerted attention to grappling with this unrelenting epidemic.

Time course for changes in aerobic capacity and body composition in overweight men and women in response to long-term exercise: the Midwest Exercise Trial (MET)

OBJECTIVE

To determine the time course for changes in aerobic capacity, body weight (BW), and composition in overweight adults in response to a supervised exercise trial with a targeted energy expenditure of 2000 kcal week(-1).

DESIGN

The Midwest Exercise Trial (MET) was a randomized, controlled, 16-month verified, supervised exercise trial. Aerobic exercise progressed to 45 min day(-1), 5 days week(-1) over 6-months and was then maintained for 10 months. Controls maintained their normal physical activity and all participants maintained ad libitum diets.

SUBJECTS

A total of 131 participants were randomized to exercise or control groups and 74 completed the intervention and all laboratory testing.

MEASUREMENTS

At baseline and months 4, 9, 12, and 16, aerobic capacity (VO(2max) ) was measured by indirect calorimetry, BW by digital scale, and fat weight and fat-free weight by hydrostatic weighing.

RESULTS

Aerobic capacity (ml kg(-1) min(-1)) increased (P<0.05) from baseline (39.2+/-5.2, mean+/-s.d.) to 9 months (48.8+/-4.3) in exercising men as well as women (32.8+/-4.2-39.6+/-5.5) with no significant changes occurring at 12 or 16 months. From baseline to 9 months BW (94.0+/-12.6-88.7+/-9.7 kg) and fat weight (26.8+/-6.8-21.8+/-4.5 kg) significantly decreased in exercising men with no changes occurring at 12 or 16 months. There were no changes in fat-free weight across the 16 months for exercising men or for BW or composition in exercising women. Further, there were no significant changes for the control men for aerobic capacity, BW, or body composition across 16 months. Women in the control group showed significant increases in weight of 2.9+/-5.5 kg and fat weight of 2.1+/-4.8 kg at 16 months only.

CONCLUSIONS

We recommend that investigations that use exercise without diet as the stimulus for weight loss have at least a 9-month duration to provide sufficient time for the full effects to be realized, should such effects be present.

Exercise-induced weight loss preferentially reduces abdominal fat

PURPOSE

To investigate whether abdominal fat is reduced in response to substantial weight loss induced by exercise in young obese men.

METHODS

Thirty obese men (mean age 19.8 +/- 0.6 yr) were evaluated before (pretraining) and after (posttraining) 4 months of regimented training in the Singapore Armed Forces. There were 30 obese male subjects (mean age 19.2 +/- 1.3 yr) without training who were monitored as control subjects. Fat free mass (FFM), fat mass, and percent body fat were determined from skinfold measurements. Differences between pre- and posttraining responses were analyzed with a paired -test.

RESULTS

Subjects lost 12.0 +/- 3.6 kg (P < 0.001) from pre- to posttraining, which was attributable to a reduction in fat mass (P < 0.001), as FFM was unchanged. Both waist circumference (WC) and hip circumference (HC) decreased (P < 0.01), the reduction in WC (13.7%) being greater than the reduction in HC (7.7%) as reflected by the decrease in waist-to-hip ratio (WHR; P < 0.001). These data reveal that large exercise-induced weight losses are associated with maintenance of FFM. The significant reduction in WHR indicates a greater mobilization of abdominal fat and a preferential loss of fat from this region.

CONCLUSIONS

Large exercise-induced weight loss is associated with a preferential reduction in abdominal fat and a corresponding maintenance of FFM. Such an effect on body composition should reduce disease risk and the eventual weight regain that typically follows diet-induced weight losses with obese subjects.

Estimating energy expenditure by heart-rate monitoring without individual calibration

Heart rate monitoring has been shown to be a valid method for measuring free-living energy expenditure at the group level, but its use in large-scale studies is limited by the need for an individual calibration of the relationship between heart rate and energy expenditure.

PURPOSE

To determine whether energy expenditure can be estimated from heart rate monitoring without individual calibration in epidemiological studies.

METHODS

Our previously validated heart rate monitoring method relies on measuring individual calibration parameters obtained from resting energy expenditure and the regression line between energy expenditure and heart rate during exercise. We developed prediction equations for these parameters using easily measured variables in a population-based study of 789 individuals. The predictive ability of these parameters was tested in a separate population-based sample (N = 97).

RESULTS

Physical activity level (PAL = total energy expenditure/basal metabolic rate) using the four estimated parameters was correlated with PAL using the measured parameters (r = 0.82, P < 0.01). Comparison of measured and estimated PAL showed that 97.9% of the scores were placed in the same or adjacent quartile.

CONCLUSION

A combination of simple measurements and heart rate monitoring produces estimates of energy expenditure that are highly correlated with those obtained using full individual calibration. This simplification of the heart rate monitoring method could extend its use in ranking individuals in epidemiological studies.

Second phase of a double-blind study clinical trial on Sibutramine for the treatment of patients suffering essential obesity: 6 months after treatment cross-over

OBJECTIVE

To evaluate the weight gain after Sibutramine 10 mg daily discontinuation. To evaluate the effect of Sibutramine 10 mg daily in patients who were on a diet for 6 months.

DESIGN

After a double-blind, placebo-controlled, parallel, prospective phase for 6 months, the treatments were crossed over and the patients continued in double-blind observation for another 6-month period.

SUBJECTS

Forty out of 44 patients who were on Sibutramine and 42/44 who were on placebo switched the trial medication. All the patients were obese at the beginning of the trial (body mass index, BMI>30 kg/m(2)). During the first phase, the weight loss in the Sibutramine group was 7.52 kg (95% confidence intervals (95% CI) 6.15; 8.9) and that in the placebo group 3.56 kg (95% CI 2.41; 4.7) (using last observation carried forward (LOCF)).

MEASUREMENTS

Body weight, BMI, waist, medical history, assessment of hunger, satiety and diet compliance, standard laboratory assessments, blood pressure, heart rate and ECG.

RESULTS

Thirty out 40 patients in the Sibutramine/placebo (S/P) group and 32 out of 42 in the placebo/Sibutramine (P/S) group completed the second phase of the trial. During the second part of the trial the S/P gained 3.21 (95% CI 2.15; 4.26) kg, 1.21 (0.82; 1.59) kg/m(2), and 2.83 (1.55; 4.12) waist cm. The P/S group lost 1.62 (2.62; 0.61), 0.67 (1.09; -0.25) kg/m(2), and 1.85 (3.18; 0.53) waist cm. Eleven patients in the S/P group suffered 14 adverse events, mainly blood pressure increase (n=4); 19 patients in the P/S group had 29 adverse events, mainly dry mouth (n=8), constipation (n=5) and blood pressure increase (n=4). Only one P/S patient withdrew because of an adverse event.

CONCLUSIONS

After Sibutramine discontinuation patients had weight gain but they did not reach the baseline body weight. No significant adverse events presented after Sibutramine discontinuation. When Sibutramine was administrated to patients after 6 months of diet, the weight plateau was broken. Early Sibutramine administration had better effects than late post-diet administration. Sibutramine was well tolerated by the patients.

The effects of a children's summer camp programme on weight loss, with a 10 month follow-up

OBJECTIVE

To assess the long-term effects of a multidisciplinary approach involving structured fun-type skill learning physical activities in the treatment of obese and overweight children.

DESIGN

A longitudinal investigation incorporating repeated measurements before and after the 8 week intervention and after the 44 week follow-up period.

METHODS

The camp programme (Massachusetts, USA) utilised structured fun-based skill learning physical activities, moderate dietary restriction and behaviour modification. The primary aims of the intervention were to reduce body mass and promote the maintenance of the reduction in body mass using an alternative to standard exercise prescription.

SUBJECTS

One-hundred and ninety-four children (64 boys and 130 girls, aged 12.6+/-2.5y) enrolled at a summer weight loss camp, of which 102 children (38 boys and 64 girls aged 13.6+/-2.4y) returned 1 y later.

MEASUREMENTS

On commencement of the programme all children were assessed for body mass and stature. At follow-up, data was available on 102 subjects for body mass and stature.

RESULTS

Over the 8 week intervention significant reductions (P= 0.00) in body mass were obtained. During the 44 week follow-up significant increases (P= 0.00) were noted in body mass, body mass index (BMI) and stature, but as expected there were large variations in the responses. One year after the initial measures had been taken mean body mass and BMI were lower than at the start of the intervention, BMI significantly so (week 0, 32.9 +/- 7.4 kg/m2; week 8 29.1 +/- 6.5 kg/m2; week 52, 30.05 +/- 7.04 kg/m2); (P= 0.00). Stature increased significantly (week 0, 1.58 +/- 0.12 m; week 52, 1.64 0.11 m) (P= 0.00) during this period, demonstrating a reduction in mean body mass over a 1 y period whilst subjects continued to increase in stature. When changes in BMI are analysed with the use of standard scores, there is a non-significant increase (P=0.07) in BMI during the follow-up phase and 89% of children had a lower BMI than at week 0.

CONCLUSIONS

These findings suggest that the use of a structured fun-based skill learning programme may provide an alternative method of exercise prescription to help children prolong the effects of the 8 week intervention. Further investigations will help identify the key factors that are necessary for long-term lifestyle modification.