Does physical activity prevent weight gain--a systematic review

Exercise Program-Induced Mood Improvement and Improved Eating in Severely Obese Adults

Background:

Using a practical setting, this study aimed to test exercise and nutrition interventions' effects on negative mood, self-regulation, and self-efficacy to control eating; and to assess the ability of mood change to predict changes in eating behavior, while accounting for changes in self-regulation and self-efficacy.

Methods:

Severely obese adults participated in a cognitive-behavioral exercise support treatment paired with either nutrition education ( n = 140) or cognitive-behavioral methods applied to improved eating ( n = 146). They were assessed on measures of overall negative mood, self-regulatory skill usage, self-efficacy to control eating when negative moods are present, and fruit and vegetable consumption at baseline and Week 26.

Results:

Significant improvements in each psychosocial variable and fruit and vegetable intake were found. Improved mood significantly predicted fruit and vegetable consumption change, R2 = 0.12, P < 0.001. Entry of changes in self-regulation and self-efficacy into the multiple regression equation significantly strengthened the variance explained, R2 = 0.18, P < 0.001.

Discussion:

Findings suggest that exercise-induced improvements in mood improve eating behaviors, with increases in self-regulation and self-efficacy adding to this effect.

Physical activity and the incidence of obesity in young African-American women

BACKGROUND

Obesity occurs more commonly among African-American women than among other racial/ethnic groups, and most weight gain occurs before middle age.

PURPOSE

The study prospectively investigated the relationship of vigorous exercise and brisk walking to the incidence of obesity (BMI ≥ 30) among African-American women aged <40 years.

METHODS

During 1995-2009 in the Black Women's Health Study, the current authors followed 20,259 African-American women who were aged <40 years and not obese at baseline. BMI, exercise, and walking were assessed at baseline and on biennial follow-up questionnaires. Data for BMI were collected through 2009. Data for exercise and walking were collected through 2007. Validation and reproducibility data indicated that reporting was more accurate for vigorous exercise than for brisk walking. Cox proportional hazards models estimated incidence rate ratios (IRRs) and 95% CIs of incident obesity for hours/week of vigorous exercise and walking relative to "little or no exercise" (<1 hour/week of vigorous exercise and <1 hour/week of brisk walking). The analyses were conducted in 2012.

RESULTS

The incidence of obesity decreased with increasing vigorous exercise; the IRR was 0.77 (95% CI=0.69, 0.85) for ≥ 7 hours/week relative to little or no exercise; the IRRs were reduced both among women with a healthy weight (BMI <25) at baseline and among women who were overweight (BMI 25-<30) at baseline. The IRRs for brisk walking for exercise and walking for transport were <1.0 for most levels of walking, but without clear trends of decreasing risk with increasing time spent walking.

CONCLUSIONS

The results suggest that vigorous exercise may reduce the incidence of obesity among young African-American women. Results for brisk walking were inconclusive.

A systematic review of physical activity levels in Native American populations in Canada and the United States in the last 50 years

Physical activity is beneficial for many chronic conditions. However, activity levels of Native Americans are not well known. This systematic review investigated if Native American populations achieve the recommended physical activity levels, compared current and past activity levels, and assessed the ability of exercise training programmes to improve health outcomes among this population. Electronic databases (e.g. MEDLINE, EMBASE) were searched and citations were cross-referenced. Included articles reported physical activity levels or investigations among Native Americans. This search identified 89 articles: self-report (n = 61), accelerometry and pedometry (n = 10), metabolic monitoring (n = 10) and physical activity interventions (n = 17). Few adults were found to meet the physical activity recommendations (27.2% [95% confidence interval = 26.9-27.5%] self-report, 9% [4-14%] accelerometry). Among children/youth, 26.5% (24.6-28.4%) (self-report) to 45.7% (42.3-49.1%) (pedometry/accelerometry) met the recommendations. Adults and children/youth were generally identified as physically inactive (via doubly labelled water). Overall, Native American adults reported lower activity levels since 2000, compared to 1990s, although similar to 1980s. Few physical activity interventions employed strong methodologies, large sample sizes and objective outcome measures. There is a clear need to increase Native American populations' physical activity. Additional research is required to evaluate exercise training programmes among this population.

[The effect of physical activity on weight loss]

BACKGROUND

Physical activity increases energy expenditure and may cause considerable negative energy balance and weight loss. The objective of this article is to review the evidence for the effect of physical activity on weight loss in overweight or obese subjects.

MATERIAL AND METHOD

A literature search was undertaken in Medline and Embase. The search was restricted to adults (> 18 years), review articles and meta-analyses published from 2000 to 2012, as well as recent randomised controlled trials (RCTs) that were not included in these meta-analyses (2009-2012).

RESULTS

Five meta-analyses based on RCT studies and 13 original studies were included. Physical activity caused a weight loss of 1 to 3 kg when physical activity was compared to a control situation, or when combined interventions including dieting and physical activity were compared to dieting alone.

INTERPRETATION

Physical activity appears to have little effect on weight loss in case of obesity. However, the results should be interpreted in light of the fact that many studies are fraught with methodological shortcomings associated with the design of the interventions and the measurement of actual completed physical activity. The effect of physical activity is therefore probably strongly underestimated in many studies.

Activity related energy expenditure, appetite and energy intake: potential implications for weight management

The aim was to investigate relationships between activity related energy expenditure (AREE), appetite ratings and energy intake (EI) in a sample of 40 male (26.4years; BMI 23.5kg/m(2)) and 42 female (26.9years; BMI 22.4kg/m(2)) participants. AREE was expressed as the residual value of the regression between total daily EE (by doubly labeled water) and resting EE (by indirect calorimetry). EI was measured using an ad libitum buffet meal and visual analogue scales measured subjective appetite ratings before and after the meal. AREE was divided into low, middle and high sex-specific tertiles. General linear models were used to investigate differences in appetite ratings and EI across AREE tertiles. Before the meal, males in the high AREE tertile had significantly lower desire to eat and lower prospective food consumption and higher feelings of fullness compared to those in the low tertile. Males in the middle tertile had significantly higher satiety quotients after the meal and lower EI compared to the other tertiles. No significant differences across tertiles were found in females. Sex differences in relationships between AREE, appetite ratings and EI may lead to differing patterns of EI and subsequent weight maintenance.

Rate of weight gain predicts change in physical activity levels: a longitudinal analysis of the EPIC-Norfolk cohort

OBJECTIVE

To investigate the relationship of body weight and its changes over time with physical activity (PA).

DESIGN

Population-based prospective cohort study (Norfolk cohort of the European Prospective Investigation into Cancer and Nutrition, EPIC-Norfolk, United Kingdom).

SUBJECTS

A total of 25 639 men and women aged 39-79 years at baseline. PA was self-reported. Weight and height were measured by standard clinical procedures at baseline and self-reported at 18-month and 10-year follow-ups (calibrated against clinical measures). Main outcome measure was PA at the 10-year follow-up.

RESULTS

Body weight and PA were inversely associated in cross-sectional analyses. In longitudinal analyses, an increase in weight was associated with higher risk of being inactive 10 years later, after adjusting for baseline activity, 18-month activity, sex, baseline age, prevalent diseases, socioeconomic status, education, smoking, total daily energy intake and alcohol intake. Compared with stable weight, a gain in weight of >2 kg per year in the short-, medium- and long-term was consistently and significantly associated with greater likelihood of physical inactivity after 10 years, with the most pronounced effect for long-term weight gain, OR=1.89 (95% CI: 1.30-2.70) in fully adjusted analysis. Weight gain of 0.5-2 kg per year over long-term was substantially associated with physical inactivity after full adjustment, OR=1.26 (95% CI: 1.11-1.41).

CONCLUSION

Weight gain (during short-, medium- and long-term) is a significant determinant of future physical inactivity independent of baseline weight and activity. Compared with maintaining weight, moderate (0.5-2 kg per year) and large weight gain (>2 kg per year) significantly predict future inactivity; a potentially vicious cycle including further weight gain, obesity and complications associated with a sedentary lifestyle. On the basis of current predictions of obesity trends, we estimate that the prevalence of inactivity in England would exceed 60% in the year 2020.

Obesity does not impair walking economy across a range of speeds and grades

Despite the popularity of walking as a form of physical activity for obese individuals, relatively little is known about how obesity affects the metabolic rate, economy, and underlying mechanical energetics of walking across a range of speeds and grades. The purpose of this study was to quantify metabolic rate, stride kinematics, and external mechanical work during level and gradient walking in obese and nonobese adults. Thirty-two obese [18 women, mass = 102.1 (15.6) kg, BMI = 33.9 (3.6) kg/m(2); mean (SD)] and 19 nonobese [10 women, mass = 64.4 (10.6) kg, BMI = 21.6 (2.0) kg/m(2)] volunteers participated in this study. We measured oxygen consumption, ground reaction forces, and lower extremity kinematics while subjects walked on a dual-belt force-measuring treadmill at 11 speeds/grades (0.50-1.75 m/s, -3° to +9°). We calculated metabolic rate, stride kinematics, and external work. Net metabolic rate (Ė net/kg, W/kg) increased with speed or grade across all individuals. Surprisingly and in contrast with previous studies, Ė net/kg was 0-6% less in obese compared with nonobese adults (P = 0.013). External work, although a primary determinant of Ė net/kg, was not affected by obesity across the range of speeds/grades used in this study. We also developed new prediction equations to estimate oxygen consumption and Ė net/kg and found that Ė net/kg was positively related to relative leg mass and step width and negatively related to double support duration. These results suggest that obesity does not impair walking economy across a range of walking speeds and grades.

Obesity-related hypertension: pathogenesis, cardiovascular risk, and treatment--a position paper of the The Obesity Society and The American Society of Hypertension

In light of the worldwide epidemic of obesity, and in recognition of hypertension as a major factor in the cardiovascular morbidity and mortality associated with obesity, The Obesity Society and The American Society of Hypertension agreed to jointly sponsor a position paper on obesity-related hypertension to be published jointly in the journals of each society. The purpose is to inform the members of both societies, as well as practicing clinicians, with a timely review of the association between obesity and high blood pressure, the risk that this association entails, and the options for rational, evidenced-based treatment. The position paper is divided into six sections plus a summary as follows: pathophysiology, epidemiology and cardiovascular risk, the metabolic syndrome, lifestyle management in prevention and treatment, pharmacologic treatment of hypertension in the obese, and the medical and surgical treatment of obesity in obese hypertensive patients.

Changes in body weight, C-reactive protein, and total adiponectin in non-obese women after 12 months of a small-volume, home-based exercise program

OBJECTIVE

Our objective was to evaluate the effects of small-volume, home-based exercise combined with slight caloric restriction on the inflammatory markers C-reactive protein and adiponectin.

METHODS

In total, 54 women were randomly assigned to one of two groups for exercise intervention: the control or home-based exercise groups. Weight, waist and hip circumferences, and inflammatory markers were measured at baseline and after 6 and 12 months. Women allocated to the home-based exercise group received a booklet explaining the physical exercises to be practiced at home at least 3 times per week, 40 minutes per session, at low-to-moderate intensity. All participants received dietary counseling aimed at reducing caloric intake by 100-300 calories per day, with a normal distribution of macro-nutrients (26-28% of energy as fat). Clinicaltrials.gov: NCT01206413 RESULTS: The home-based exercise group showed a significantly greater reduction in weight and body mass index at six months, but no difference between groups was observed thereafter. With regard to the inflammatory markers, a greater but non-statistically significant reduction was found for C-reactive protein in the home-based exercise group at six months; however, this difference disappeared after adjusting for weight change. No differences in adiponectin were found at the 6- or 12-month follow-up.

CONCLUSION

Small-volume, home-based exercise did not promote changes in inflammatory markers independent of weight change.

Obesity-related hypertension: pathogenesis, cardiovascular risk, and treatment: a position paper of The Obesity Society and the American Society of Hypertension

In light of the worldwide epidemic of obesity, and in recognition of hypertension as a major factor in the cardiovascular morbidity and mortality associated with obesity, The Obesity Society and the American Society of Hypertension agreed to jointly sponsor a position paper on obesity-related hypertension to be published jointly in the journals of each society. The purpose is to inform the members of both societies, as well as practicing clinicians, with a timely review of the association between obesity and high blood pressure, the risk that this association entails, and the options for rational, evidenced-based treatment. The position paper is divided into six sections plus a summary as follows: pathophysiology, epidemiology and cardiovascular risk, the metabolic syndrome, lifestyle management in prevention and treatment, pharmacologic treatment of hypertension in the obese, and the medical and surgical treatment of obesity in obese hypertensive patients.

Combined impact of lifestyle factors on prospective change in body weight and waist circumference in participants of the EPIC-PANACEA study

Background

The evidence that individual dietary and lifestyle factors influence a person’s weight and waist circumference is well established; however their combined impact is less well documented. Therefore, we investigated the combined effect of physical activity, nutrition and smoking status on prospective gain in body weight and waist circumference.

Methods

We used data of the prospective EPIC-PANACEA study. Between 1992 and 2000, 325,537 participants (94,445 men and 231,092 women, aged between 25–70) were recruited from nine European countries. Participants were categorised into two groups (positive or negative health behaviours) for each of the following being physically active, adherent to a healthy (Mediterranean not including alcohol) diet, and never-smoking for a total score ranging from zero to three. Anthropometric measures were taken at baseline and were mainly self-reported after a medium follow-up time of 5 years.

Results

Mixed-effects linear regression models adjusted for age, educational level, alcohol consumption, baseline body mass index and follow-up time showed that men and women who reported to be physically active, never-smoking and adherent to the Mediterranean diet gained over a 5-year period 537 (95% CI −706, −368) and 200 (−478, −87) gram less weight and 0.95 (−1.27, −0.639) and 0.99 (−1.29, −0.69) cm less waist circumference, respectively, compared to participants with zero healthy behaviours.

Conclusion

The combination of positive health behaviours was associated with significantly lower weight and waist circumference gain.

Lifestyle management in the metabolic syndrome

Type 2 diabetes and metabolic syndrome are two of the fastest growing public health problems in both developed and developing countries. Cardiovascular disease is the most prevalent complication of type 2 diabetes and the metabolic syndrome. Overweight, obesity, or weight gain has been shown to be an important risk factor for the development of type 2 diabetes and an important component of the metabolic syndrome. Physical inactivity is another important risk factor for the development of type 2 diabetes. Data from prospective studies have shown that at least 30 min/day of moderate to vigorous physical activity can prevent type 2 diabetes. Moderate or high levels of physical fitness are effective in preventing type 2 diabetes. Results from clinical trials have indicated that lifestyle changes, including dietary modification and increase in physical activity, can prevent type 2 diabetes. Analyses from prospective studies have confirmed that healthy diets are effective and safe ways to prevent type 2 diabetes and the metabolic syndrome. Public health messages, health care professionals, and the health care system should aggressively promote physical activity and responsible nutritional habits during occupation, leisure time, and daily life and prevent overweight and obesity.

Supported exercise improves controlled eating and weight through its effects on psychosocial factors: extending a systematic research program toward treatment development

BACKGROUND

Behavioral weight-loss treatments have been overwhelmingly unsuccessful. Many inadequately address both behavioral theory and extant research--especially in regard to the lack of viability of simply educating individuals on improved eating and exercise behaviors.

OBJECTIVE

The aim was to synthesize research on associations of changes in exercise behaviors, psychosocial factors, eating behaviors, and weight; and then conduct further direct testing to inform the development of an improved treatment approach.

METHODS

A systematic program of health behavior-change research based on social cognitive theory, and extensions of that theory applied to exercise and weight loss, was first reviewed. Then, to extend this research toward treatment development and application, a field-based study of obese adults was conducted. Treatments incorporated a consistent component of cognitive-behaviorally supported exercise during 26 weeks that was paired with either standard nutrition education (n = 183) or cognitive-behavioral methods for controlled eating that emphasized self-regulatory methods such as goal setting and caloric tracking, cognitive restructuring, and eating cue awareness (n = 247).

RESULTS

Both treatment conditions were associated with improved self-efficacy, self-regulation, mood, exercise, fruit and vegetable consumption, weight, and waist circumference; with improvements in self-regulation for eating, fruit and vegetable consumption, weight, and waist circumference significantly greater in the cognitive-behavioral nutrition condition. Changes in exercise- and eating-related self-efficacy and self-regulation were associated with changes in exercise and eating (R(2) = 0.40 and 0.17, respectively), with mood change increasing the explanatory power to R(2) = 0.43 and 0.20. Improved self-efficacy and self-regulation for exercise carried over to self-efficacy and self-regulation for controlled eating (β= 0.53 and 0.68, respectively).

CONCLUSIONS

Development and longitudinal testing of a new and different approach to behavioral treatment for sustained weight loss that emphasizes exercise program-induced psychosocial changes preceding the facilitation of improved eating and weight loss should be guided by our present research.

Body composition changes after weight-loss interventions for overweight and obesity

BACKGROUND & AIMS

Weight-loss interventions to correct overweight and obesity are very popular but often inappropriate and unsuccessful.

METHODS

In this review we evaluated studies on body composition changes during and after different medical and surgical interventions aimed at achieving stable weight loss in overweight and obese individuals.

RESULTS

Most of the available literature and good clinical practice observations deal mainly with post-menopausal overweight and obese women, and, to a lesser extent adolescents and elderly, female and male, populations. These studies suggest that weight-loss maintenance interventions should have greater consideration and priority than simple weight-loss treatments. At a long term follow up (over one year), relatively high protein, moderately low calorie, low glycemic index diets, associated with a daily, moderate intensity, physical exercise (of at least 30 min), appear to be more successful in limiting long term relapse, maintaining fat free mass and achieving the highest fat loss. Diet alone or physical exercise alone does not produce similar results. Health professional training and practice also appear a challenging target.

CONCLUSIONS

Adequate dietetic advice plus regular physical exercise avoid the fat-free-mass loss usually observed in the relapse of the weight cycling syndrome and prevent the onset of sarcopenic obesity.

Maintenance of lifestyle changes: 3-year results of the Groningen Overweight and Lifestyle study

OBJECTIVE

This study aims to evaluate the three-year effect of lifestyle counseling by a nurse practitioner (NP) on physical activity (PA) and dietary intake compared with usual care by a general practitioner (GP).

METHODS

At baseline, subjects were randomly allocated to the NP group (n = 225) or to the GP group (n = 232). The NP group received a low-intensive lifestyle intervention for three years by the NP and the GP group received one consultation by the GP and thereafter usual care. PA and dietary intake were assessed with questionnaires at baseline, 1 year follow-up and 3 year follow-up.

RESULTS

After three years, leisure-time activity increased and favorable improvements towards a healthy diet were made for both groups. These three-year changes in PA and diet did not differ significantly between groups. Changes in PA and dietary habits after one year were practically maintained after 3 years, because only small relapses were found.

CONCLUSION

After three years, subjects were more physically active and had a healthier diet compared to baseline. Lifestyle counseling by NP resulted in similar lifestyle changes compared to GP consultation.

PRACTICE IMPLICATIONS

NPs could also advice patients at cardiovascular risk by lifestyle counseling, to possibly reduce GP barriers.

Physical activity and the risk of becoming overweight or obese in middle-aged and older women

Although public health campaigns stress leisure time physical activity (LTPA) as essential for obesity prevention, few epidemiological studies have focused on the association of specific types and intensities of LTPA and the clinical endpoints of overweight and obesity. Therefore, we prospectively assessed whether moderate- and vigorous-intensity as well as total LTPA were associated with the risk of becoming either overweight or obese using a prospective cohort design of 19,003 women enrolled in the Women's Health Study (WHS). Women reported their participation in walking and LTPA at baseline. During a median follow-up of 11.6 years, 7,865 women became overweight or obese. In multivariable-adjusted models that included demographic, lifestyle, and dietary factors, both vigorous-intensity and total LTPA showed a modest inverse relationship with the development of overweight/obesity. The hazard ratios (HR) and 95% confidence interval (CI) for the highest categories of vigorous-intensity LTPA (>2,000 kcal/week) and total LTPA (>3,000 kcal/week) compared with no LTPA were 0.79 (0.71-0.89) and 0.87 (0.78-0.96), respectively. In addition, a greater percentage of total LTPA spent performing vigorous intensity activities was associated with a lower risk of overweight/obesity (multivariable HR 0.93, 95% CI 0.87-0.98 for performing >50% compared with <50% of activity as vigorous). In conclusion, higher amounts of total LTPA should be encouraged to prevent obesity. Among those willing to participate in vigorous LTPA, and for whom such activities are not contraindicated, vigorous LPTA should be encouraged.

Environmental factors associated with overweight among adults in Nigeria

BACKGROUND

Understanding environmental factors related to obesity can inform interventions for the world wide obesity epidemic, yet no study has been conducted in this context in Africa. This study examined associations between neighbourhood environment variables and overweight in Nigerian adults.

METHODS

A total of 1818 randomly selected residents (age: 20-65 years, 40% female, 31% overweight and 61.2% response) living in high and low socioeconomic (SES) neighbourhoods in Metropolitan Maiduguri, Nigeria, participated in a cross-sectional study. Anthropometric measurements of height and weight and an interview-assisted self-reported measure of 16 items of perceived neighborhood environments were conducted. The primary outcome was overweight (body mass index [BMI] > or = 25 kg/m(2)) vs. normal weight (BMI = 18.5-24.9 kg/m(2)).

RESULTS

After adjustment for sociodemographic variables, overweight was associated with distant access to commercial facilities (odds ratio [OR], 1.49; 95% confidence interval [CI], 1.02- 2.18), poor neighbourhood aesthetics (OR, 1.58; 95% CI, 1.16-2.09), perceiving garbage and offensive odours in the neighbourhood (OR, 1.41; 95% CI, 1.05-1.89) and feeling unsafe from crime at night (OR, 1.47; 95% CI, 1.13- 1.91) and unsafe from traffic (OR, 1.56; 95% CI, 1.17-2.07) in the total sample. Significant interactions regarding overweight were found between gender and four environmental variables, with low residential density (OR, 1.39; 95% CI, 1.02-1.93) and poorly maintained pedestrian pathways (OR, 1.89; 95% CI, 1.13-3.17) associated with overweight in men only, and absence of beautiful things (OR, 2.23; 95% CI, 1.42-3.50) and high traffic making it unsafe to walk (OR, 2.39; 95% CI, 1.49-3.83) associated with overweight in women only. There were few significant interactions between environmental factors and neighborhood SES regarding overweight.

CONCLUSION

Neighbourhood environment factors were associated with being overweight among Nigerian adults. These findings support previous reports in international literature, but should be replicated in other African studies before any firm conclusions can be drawn.

Improving psychological treatment for obesity. Which eating behaviours should we target?

People who are obese and want to lose weight without surgery deserve the best treatment that we can offer. In the absence of robust and enduring treatment effects for psychological interventions for obesity, it is useful to return to first principles. From a behavioural perspective, the first task is to identify the full range of target eating behaviours involved in obesity. Surprisingly, a consensus on the key target eating behaviours typically involved in obesity does not seem to currently exist. In this opinion piece, we discuss which eating behaviours might be important to consider when treating obesity, and provide a self-report questionnaire that aims to identify these behaviours (see Supplementary material). We believe that it is important to be aware of the full range of eating behaviours that are potentially relevant to obesity, as different eating behaviours may be problematic for different people. Target eating behaviours associated with obesity may also be different from those of key relevance to eating disorders. Factors that should be taken into account when assessing target eating behaviours and developing effective treatments for obesity are also discussed. Particular attention is paid to 'grazing,' a relatively neglected high risk eating behaviour for weight gain.

Behavioral treatment of obesity

This review has shown that behavioral treatment is effective in inducing a 10% weight loss, which is sufficient to significantly improve health. Weight loss maintenance is challenging for most patients. Long-term outcomes have the potential to be improved through various methods including prolonging contact between patients and providers (either in the clinic or via Internet or telephone), facilitating high amounts of physical activity, or combining lifestyle modification with pharmacotherapy. Innovative programs also are being developed to disseminate behavioral approaches beyond traditional academic settings.

Energetics and biomechanics of inclined treadmill walking in obese adults

Brisk walking is a recommended form of exercise for obese individuals. However, lower-extremity joint loads and the associated risk of musculoskeletal injury or pathological disease increase with walking speed. Walking uphill at a slower speed is an alternative form of moderate intensity exercise that may reduce joint loading.

PURPOSE

The purpose of this study was to quantify the energetics and biomechanics of level and uphill walking in obese adults. We hypothesized that compared to brisk level walking, walking slower up a moderate incline would reduce lower-extremity net muscle moments while providing appropriate cardiovascular stimulus.

METHODS

Twelve obese adult volunteers, with mass of 100.5±15.7 kg and body mass index of 33.4±2.6 kg·m (mean±SD), participated in this study. We measured oxygen consumption, ground reaction forces, and three-dimensional lower-extremity kinematics while subjects walked on a dual-belt force-measuring treadmill at several speed (0.50-1.75 m·s) and grade (0°-9°) combinations. We calculated metabolic rate, loading rates, and net muscle moments at the hip, knee, and ankle for each condition.

RESULTS

Metabolic rates were similar across trials and were of moderate intensity (48.5%-59.8% of VO2max). Walking slower uphill significantly reduced loading rates and lower-extremity net muscle moments compared with faster level walking. Peak knee extension and adduction moments were reduced by ∼19% and 26%, respectively, when subjects walked up a 6° incline at 0.75 m·s versus level walking at 1.50 m·s.

CONCLUSIONS

These results suggest that walking at a relatively slow speed up a moderate incline is a potential exercise strategy that may reduce the risk of musculoskeletal injury/pathological disease while providing proper cardiovascular stimulus in obese adults.

Causes and consequences of obesity: the contribution of recent twin studies

Obesity is a genetically complex disorder that produces a myriad of health problems. Most of the recognized complications of obesity are not only strongly influenced by lifestyle factors, but also present with independent genetic predispositions that are notoriously difficult to disentangle in humans. Most studies on the causes and consequences of acquired obesity are encumbered by the incomplete ability to control for genetic influences. However, utilizing a unique experiment of nature, namely monozygotic twins (MZ) discordant for obesity as 'clonal controls' of obese and non-obese individuals has enabled the fine characterization of the effects and possible antecedents of acquired obesity while controlling for the genetic background, as well as pointed to novel obesity predisposing candidate genes. This review is a distillation of the findings from more than 10 years of research done in an exceptionally well-characterized collection of MZ and dizygotic (DZ) twins, based on the Finnish Twin Cohorts. Topics covered include the nature of development of obesity from the childhood onwards, the role of exercise in modifying the genetic susceptibility, the resulting inflammatory, prediabetic and preatherosclerotic changes in whole body and adipose tissue physiology, as well as the newest insights provided by the omics revolution.

Children's weight and participation in organized sports

AIMS

Literature dealing with the impact of organized sports on children's weight has been marked by a lack of consensus. A major weakness characterizing most of this research is a lack of proper measurement methods. This paper seeks to fill an important knowledge gap through careful application of econometric methods.

METHODS

Estimations are carried out using data on 1,400 children attending 6th grade in 2008 in the municipality of Aalborg, Denmark. We use standard ordinary least squares (OLS) and class fixed effects to explore the effect of sports participation on body mass index (BMI) as well as underweight, overweight and obesity.

RESULTS

Results indicate that participation in organized sports reduced BMI by 2.1%. Likewise it reduced the likelihood of being overweight by 8.2 percentage points and obese by 3.1 percentage points.

CONCLUSIONS

It is the unique dataset combined with econometric methods that distinguishes our contribution from that of others in the field, thereby offering new insight. Results using statistically sound methods suggest that participation in organized sports has a beneficial effect on children's weight.

Exercise autonomous motivation predicts 3-yr weight loss in women

PURPOSE

This study evaluated exercise-related predictors of successful long-term weight control in women by analyzing the extent to which sustained exercise participation and self-determination theory (SDT)-based exercise motivation variables mediated the impact of a behavioral weight control intervention on 3-yr weight change.

METHODS

Longitudinal randomized controlled trial consisting of a 1-yr SDT-based intervention and a 2-yr follow-up with 221 female participants (means ± SD: age = 37.6 ± 7 yr, body mass index = 31.6 ± 4.1 kg·m(-2)). The tested model incorporated experimentally manipulated perceived need support, motivational regulations, and 2-yr exercise adherence as mediators of the intervention's impact on 3-yr weight change. Paths were tested using partial least squares analysis. Where there were significant intervening paths, tests of mediation were conducted.

RESULTS

Treatment had significant effects on 1- and 2-yr autonomous regulations, 2-yr physical activity, and 3-yr weight change, fully mediated by the tested paths (effect ratio = 0.10-0.61). Moderate and vigorous exercise at 2 yr had a significant effect (P < 0.001) on weight loss success at 3 yr and partially mediated the effect of treatment on weight change. The 2-yr autonomous regulation effects on follow-up weight change were only partially mediated by physical activity (effect ratio = 0.42).

CONCLUSIONS

This application of SDT to physical activity and weight management showed that not all types of motivation predict long-term behavioral outcomes and that sustained moderate and vigorous exercise mediated long-term weight change. It provides strong evidence for a link between experimentally increased autonomous motivation and exercise and long-term weight loss maintenance. Results highlight the importance of interventions targeting the internalization of exercise behavioral regulation and making exercise and physical activity positive and meaningful experiences rather than simply focusing on immediate behavior change in overweight/obese women.

Dietary habits and inadequate control of blood pressure in hypertensive adults assisted by a Brazilian Family Doctor Program

Objective

To estimate dietary habits and other factors associated with inadequate blood pressure (BP) control in hypertensive patients adherent to antihypertensive drug treatment assisted by a Brazilian Family Doctor Program (FDP).

Design

A cross-sectional study.

Setting

FDP units, Niterói, Rio de Janeiro, Brazil.

Subjects

We included data from both male and female participants aged ≥20 years. Participants completed a standardized questionnaire containing questions related to demographics, socio-economic factors, comorbidities and lifestyle, as well as a validated FFQ and eleven additional qualitative questions to investigate dietary habits. Food items were divided into sixteen groups. Medical consultations were performed, BP measurements were taken, blood and urine samples were assessed and anthropometric and nutritional status was evaluated.

Results

Individuals with inadequate BP control presented higher BMI values (prevalence ratio (PR) = 1·027, 95 % CI 1·009, 1·045) and also consumed more meat (PR = 1·091, 95 % CI 1·022, 1·165), which are potentially modifiable variables. Higher levels of serum creatinine (PR = 1·894, 95 % CI 1·241, 2·892) were also associated with inadequate BP control, as were skin colour (white). After inclusion of the Na excretion index, which is an indirect measure of salt intake, a slight decrease was observed in the PR for meat, which resulted in loss of statistical significance.

Conclusions

The results indicate that salt consumption, skin colour, BMI and serum creatinine are associated with inadequate BP control.

Objectively measured physical activity and obesity prevention in children, adolescents and adults: a systematic review of prospective studies

This study aimed at synthesizing the prospective associations between measured physical activity (PA) and change in adiposity in children, adolescents and adults following from two previous reviews. Search terms were adapted and a systematic literature search was conducted (January 2000-September 2008) and later updated (up to October 2009), considering observational and intervention studies of weight gain that measured both PA and body composition. Sixteen observational studies (six comprising adults) and five trials (one comprising adults) were eligible. For consistency, whenever possible either baseline PA energy expenditure or accelerometer output (counts min(-1) ) and change in per cent body fat were the extracted exposure and outcome measures. Results of observational studies suggest that PA is not strongly prospectively related with adiposity: five studies on children and three on adults reported no association between baseline PA and change in adiposity, one study found a weak positive association and the other studies observed a weak negative association. Negative associations were more frequently observed in studies that analysed the association between change in the exposure and outcome. Intervention studies show generally no effect on either PA or adiposity. In conclusion, despite the well-established health benefits of PA, it may not be a key determinant of excessive gain in adiposity.

MVPA is associated with lower weight gain in 8-10 year old children: a prospective study with 1 year follow-up

BACKGROUND

Studies relating physical activity (PA) to weight gain in children have produced mixed results, although there is some evidence for stronger associations with more intense physical activities. The present study tested the hypothesis that weight gain over one year in 8-10 year olds would be more strongly predicted by moderate and vigorous physical activity (MVPA) than total physical activity (total PA) or sedentary behaviour.

METHODOLOGY

Participants were 280 children taking part in the Physical Exercise and Appetite in Children Study (PEACHES). Weight status was assessed using body mass index (BMI), fat mass index (FMI), and waist circumference (WC) in school Year 4 (baseline; age 8.7 yrs) and Year 5 (follow-up; age 9.7 yrs). Physical activity was measured at baseline using the Actigraph GT1M accelerometer to assess total PA (mean accelerometers counts per minute), MVPA; ≥ 4000 counts per minute) and sedentary time (<100 counts per minute).

PRINCIPAL FINDINGS

After adjustment for baseline BMI, SES, sex and ethnicity, MVPA was significantly associated with follow-up BMI (adjusted β  = -0.07; p = 0.002). This association was independent of total PA or sedentary time. Similar results were observed for FMI; again MVPA was significantly associated with follow up FMI (β = -0.16; p = 0.001) independent of total PA or sedentary time. The pattern was similar for WC (β = -0.07), but the association between MVPA and WC did not reach significance at p = 0.06.

CONCLUSION

The results of this study strongly support promotion of MVPA in children.

Relationship of exercise volume with change in depression and its association with self-efficacy to control emotional eating in severely obese women

Introduction. Exercise may improve one's perceived ability to control overeating related to negative emotions through psychological pathways such as reduced depression; however, the volume required is unclear. Methods. Severely obese women (N = 88) participated in a 24-week exercise and nutrition treatment incorporating self-regulatory skills training, and were assessed on depression, self-efficacy, self-regulatory skills usage, weight, and waist circumference, at baseline and treatment end. Results. Subjects completing low-moderate (40–149.9 minutes/week) and public health (≥150 minutes/week) volumes of exercise had significant and similar reductions in depression scores. No significant changes were found for those completing <40 minutes/week. For all subjects aggregated, depression change was significantly related to change in self-efficacy to control emotional eating; however, this relationship was completely mediated by changes in self-regulatory skill usage. When changes in depression, self-efficacy, and self-regulatory skills usage were entered into multiple regression equations as predictors, only self-regulatory skill changes explained significant unique portions of the overall variance in weight and weight circumference change. Discussion. Exercise of less than half the public health recommendation was associated with depression improvement, with no dose-response effect. Changes in depression, self-efficacy, and self-regulation may be salient variables to account for in behavioral weight-loss treatment research.

Energy expenditure in adults living in developing compared with industrialized countries: a meta-analysis of doubly labeled water studies

BACKGROUND

There is an assumption that people in developing countries have a higher total energy expenditure (TEE) and physical activity level (PAL) than do people in developed nations, but few objective data for this assertion exist.

OBJECTIVE

We conducted a meta-analysis of TEE and PAL by using data from countries that have a low or middle human development index (HDI) compared with those with a high HDI to better understand how energy-expenditure variables are associated with development status and population differences in body size.

DESIGN

We performed a literature search for studies in which energy expenditure was measured by using doubly labeled water. Mean data on age, weight, body mass index (BMI; in kg/m(2)), TEE, and PAL were extracted, and HDI status was assessed. Pooled estimates of the mean effect by sex were obtained, and the extent to which age, weight, HDI status, and year of publication explained heterogeneity was assessed.

RESULTS

A total of 98 studies (14 studies from low- or middle-HDI countries) that represented 183 cohorts and 4972 individuals were included. Mean (±SE) BMI was lower in countries with a low or middle HDI than in those with a high HDI for both men and women (22.7 ± 1.0 compared with 26.0 ± 0.7, respectively, in men and 24.3 ± 0.7 compared with 26.6 ± 0.4, respectively, in women). In meta-regression models, there was an inverse association of age (P < 0.001) and a positive association of weight (P < 0.001) with TEE for both sexes; there was an association of age only in men with PAL (P < 0.001). There was no association of HDI status with either TEE or PAL.

CONCLUSION

TEE adjusted for weight and age or PAL did not differ significantly between developing and industrialized countries, which calls into question the role of energy expenditure in the cause of obesity at the population level.

Maintaining a high physical activity level over 20 years and weight gain

CONTEXT

Data supporting physical activity guidelines to prevent long-term weight gain are sparse, particularly during the period when the highest risk of weight gain occurs.

OBJECTIVE

To evaluate the relationship between habitual activity levels and changes in body mass index (BMI) and waist circumference over 20 years.

DESIGN, SETTING, AND PARTICIPANTS

The Coronary Artery Risk Development in Young Adults (CARDIA) study is a prospective longitudinal study with 20 years of follow-up, 1985-1986 to 2005-2006. Habitual activity was defined as maintaining high, moderate, and low activity levels based on sex-specific tertiles of activity scores at baseline. Participants comprised a population-based multicenter cohort (Chicago, Illinois; Birmingham, Alabama; Minneapolis, Minnesota; and Oakland, California) of 3554 men and women aged 18 to 30 years at baseline.

MAIN OUTCOME MEASURES

Average annual changes in BMI and waist circumference.

RESULTS

Over 20 years, maintaining high levels of activity was associated with smaller gains in BMI and waist circumference compared with low activity levels after adjustment for race, baseline BMI, age, education, cigarette smoking status, alcohol use, and energy intake. Men maintaining high activity gained 2.6 fewer kilograms (0.15 BMI units per year; 95% confidence interval [CI], 0.11-0.18 vs 0.20 in the lower activity group; 95% CI, 0.17-0.23), and women maintaining higher activity gained 6.1 fewer kilograms (0.17 BMI units per year; 95% CI, 0.12-0.21 vs 0.30 in the lower activity group; 95% CI, 0.25-0.34). Men maintaining high activity gained 3.1 fewer centimeters in waist circumference (0.52 cm per year; 95% CI, 0.43-0.61 cm vs 0.67 cm in the lower activity group; 95% CI,0.60-0.75 cm) and women maintaining higher activity gained 3.8 fewer centimeters(0.49 cm per year; 95% CI, 0.39-0.58 cm vs 0.67 cm in the lower activity group; 95% CI, 0.60-0.75 cm) [corrected].

CONCLUSION

Maintaining high activity levels through young adulthood may lessen weight gain as young adults transition to middle age, particularly in women.

Maintenance of weight loss after lifestyle interventions for overweight and obesity, a systematic review

Lifestyle interventions can reduce body weight, but weight regain is common and may particularly occur with higher initial weight loss. If so, one may argue whether the 10% weight loss in clinical guidelines is preferable above a lower weight loss. This systematic review explores the relation between weight loss during an intervention and weight maintenance after at least 1 year of unsupervised follow-up. Twenty-two interventions (during at least 1 month) in healthy overweight Caucasians were selected and the mean percentages of weight loss and maintenance were calculated in a standardized way. In addition, within four intervention groups (n > 80) maintenance was calculated stratified by initial weight loss (0-5%, 5-10%, >10%). Overall, mean percentage maintenance was 54%. Weight loss during the intervention was not significantly associated with percentage maintenance (r = -0.26; P = 0.13). Percentage maintenance also not differed significantly between interventions with a weight loss of 5-10% vs. >10%. Consequently, net weight loss after follow-up differed between these categories (3.7 vs. 7.0%, respectively; P < 0.01). The analyses within the four interventions confirmed these findings. In conclusion, percentage maintenance does not clearly depend on initial weight loss. From this perspective, 10% or more weight loss can indeed be encouraged and favoured above lower weight loss goals.

"My quality of life is worse compared to my earlier life": Living with chronic problems after weight loss surgery

Weight loss surgery is commonly regarded as improving individuals' health and social life, and resulting in a happier and more active life for those defined as "morbidly obese." However, some researchers have started to doubt whether these positive outcomes apply to everyone and this article explores this doubt further. More specifically, we focus on the experiences of women whose life situation became worse after weight loss surgery. The material draws on qualitative interviews of five Norwegian women undergoing the irreversible gastric bypass procedure. Our findings illustrate that the women lived seemingly "normal" lives prior to the surgery with few signs of illness. Worries about future illness as well as social stigma because of their body shape motivated them to undergo weight loss surgery. After the surgery, however, their situation was profoundly changed and their lives were dramatically restricted. Chronic pain, loss of energy, as well as feelings of shame and failure for having these problems not only limited their social lives but it also made them less physically active. In addition, they had difficulties taking care of their children, and functioning satisfactorily at work. Accordingly, the women gradually felt more "disabled," regarding themselves as "outsiders" whose problems needed to be kept private. The results highlight some "subtle" consequences of weight loss surgery, particularly the shame and stigma experienced by those whose lives became dramatically worse. Living in a society where negative impacts of weight loss surgery are more or less neglected in research as well as in the public debate the women seemed to suffer in silence. Their problems were clearly present and felt in the body but not talked about and shared with others.

Acute and long-term effects of exercise on appetite control: is there any benefit for weight control?

PURPOSE OF REVIEW

To examine the relationship between energy intake, appetite control and exercise, with particular reference to longer term exercise studies. This approach is necessary when exploring the benefits of exercise for weight control, as changes in body weight and energy intake are variable and reflect diversity in weight loss.

RECENT FINDINGS

Recent evidence indicates that longer term exercise is characterized by a highly variable response in eating behaviour. Individuals display susceptibility or resistance to exercise-induced weight loss, with changes in energy intake playing a key role in determining the degree of weight loss achieved. Marked differences in hunger and energy intake exist between those who are capable of tolerating periods of exercise-induced energy deficit, and those who are not. Exercise-induced weight loss can increase the orexigenic drive in the fasted state, but for some this is offset by improved postprandial satiety signalling.

SUMMARY

The biological and behavioural responses to acute and long-term exercise are highly variable, and these responses interact to determine the propensity for weight change. For some people, long-term exercise stimulates compensatory increases in energy intake that attenuate weight loss. However, favourable changes in body composition and health markers still exist in the absence of weight loss. The physiological mechanisms that confer susceptibility to compensatory overconsumption still need to be determined.

Perceived intrinsic barriers to physical activity among rural mothers

BACKGROUND

The purpose of this study was to identify and determine the influence of perceived intrinsic barriers to physical activity among mothers living in rural areas.

METHODS

Mothers were identified through a study of child-parent dyads in the predominantly rural states of New Hampshire and Vermont. Using a telephone interview, we asked mothers (n = 1691) about their level of physical activity and assessed eight potential barriers to physical activity. Data were analyzed using chi-square tests, t tests, and analysis of variance (ANOVA) comparisons for groups within each variable. We used multiple regression analysis to assess associations between perceived barriers to physical activity and self-reported levels of physical activity.

RESULTS

Each barrier was inversely associated with physical activity. Multivariate models that included terms for all potential barriers and covariates identified three barriers associated with lower levels of physical activity: lack of self-discipline, lack of time, and lack of interest.

CONCLUSIONS

Rural mothers are less likely to be physically active if they identify lack of self-discipline, time, or interest as barriers, suggesting that they have difficulty prioritizing exercise for themselves. Interventions aimed at increasing physical activity for mothers should specifically consider these barriers. One possible solution may be to support infrastructure that facilitates active living as the default option, to remove the issue of having to purposefully engage in physical activity as a separate aspect of a mother's life.

Perceived intrinsic barriers to physical activity among rural mothers

BACKGROUND

The purpose of this study was to identify and determine the influence of perceived intrinsic barriers to physical activity among mothers living in rural areas.

METHODS

Mothers were identified through a study of child-parent dyads in the predominantly rural states of New Hampshire and Vermont. Using a telephone interview, we asked mothers (n = 1691) about their level of physical activity and assessed eight potential barriers to physical activity. Data were analyzed using chi-square tests, t tests, and analysis of variance (ANOVA) comparisons for groups within each variable. We used multiple regression analysis to assess associations between perceived barriers to physical activity and self-reported levels of physical activity.

RESULTS

Each barrier was inversely associated with physical activity. Multivariate models that included terms for all potential barriers and covariates identified three barriers associated with lower levels of physical activity: lack of self-discipline, lack of time, and lack of interest.

CONCLUSIONS

Rural mothers are less likely to be physically active if they identify lack of self-discipline, time, or interest as barriers, suggesting that they have difficulty prioritizing exercise for themselves. Interventions aimed at increasing physical activity for mothers should specifically consider these barriers. One possible solution may be to support infrastructure that facilitates active living as the default option, to remove the issue of having to purposefully engage in physical activity as a separate aspect of a mother's life.

Evaluation of physical activity measures used in middle-aged women

PURPOSE

To evaluate the reliability and validity of five commonly used physical activity questionnaires (PAQ) in women aged 45-65 yr with varying physical activity (PA) levels.

METHODS

Data were obtained from the Evaluation of Physical Activity Measures in Middle-aged Women (PAW) Study and included 66 women (aged 52.6 +/- 5.4 yr). PAQ evaluated include Modifiable Activity Questionnaire (past week and past month version), Nurses' Health Study PAQ, Active Australia Survey, and Women's Health Initiative PAQ. Intraclass correlation coefficients (ICC) between administrations of the PAQ were used to assess test-retest reliability. Spearman rank-order correlation coefficients were used to examine the associations of PA and physical fitness data with PAQ summary estimates.

RESULTS

Accelerometer-determined median (25th, 75th percentiles) times (min.d) spent in moderate-lifestyle [760-1951 counts (ct)], moderate-walk (1952-5724 ct), vigorous (> or =5725 ct), and combined moderate and vigorous PA (MVPA > or = 1952 ct) during the 35 d of observation were 66.0 (51.2, 81.3), 23.1 (14.1, 34.6), 0.4 (0.0, 2.3), and 24.3 (15.9, 41.6) min, respectively. The PAQ were shown to be reproducible and relatively stable over time (ICC = 0.32 to 0.91) and were associated with total counts per day (ct.d, 0.46 to 0.60, all P < 0.001), and most were associated with many facets of physical fitness, including cardiorespiratory fitness (0.36 to 0.46, P < 0.01), body composition (-0.27 to -0.34, P < 0.05), and muscular fatigue (-0.25 to -0.44, P < 0.05).

CONCLUSIONS

The PAQ evaluated in this study were shown to be reliable and associated with PA and physical fitness measures. Current findings support the utility of these PAQ for PA assessment in research studies of middle-aged women.

Effect of change in physical activity on body fatness over a 10-y period in the Doetinchem Cohort Study

BACKGROUND

Obesity is related to many adverse health-related outcomes.

OBJECTIVE

We investigated whether changes in physical activity were related to less gain in either body weight or waist circumference (WC).

DESIGN

The association between prospectively assessed physical activity and either body weight or WC was examined in 4944 participants of the Doetinchem Study (men and women aged between 26 and 66 y at baseline). Information on physical activity (derived from a validated physical activity index), body weight, and WC, measured according to standardized procedures, was collected at baseline and at the 5- and 10-y follow-ups.

RESULTS

Random mixed-effects models showed that a single measurement of physical activity was not clearly related to change in body weight and WC over a 5-y period. However, analyses of repeated measures showed that compared with those who maintained their activity level, those who increased their physical activity over a 5-y period had less gain in WC ( minus 0.35 cm; 95% CI: minus 0.65, minus 0.05 cm) and possibly in body weight ( minus 280 g; 95% CI: minus 620, 5 g). Most importantly, these effects were sustained (although not significantly) in the consecutive 5 y for WC ( minus 0.56 cm; 95% CI: minus 108, 0.04 cm) and for body weight ( minus 590 g; 95% CI: minus 1005, minus 130 g), which indicated that physical activity was truly a determinant of body size changes.

CONCLUSIONS

An increase in physical activity was associated with a statistically significant lower gain in body weight and in WC, which was maintained during the following 5 y. These findings support the need for public health programs that promote physical activity.

A randomized clinical trial of home-based exercise combined with a slight caloric restriction on obesity prevention among women

OBJECTIVE

The study investigated the effectiveness of home-based exercise combined with a slight caloric restriction on weight change during 12 months in non-obese women.

METHODS

A randomized clinical trial with a factorial design was conducted from 2003 to 2005. Two hundred three middle-aged women (Rio de Janeiro/Brazil), 25-45 years, were randomly assigned to one of two groups: control (CG) and home-based exercise (HB). The HB group received a booklet on aerobic exercise that could be practiced at home (3 times/week-40 min/session), in low-moderate intensity, during 12 months. Both groups received dietary counseling aimed at a slight energy restriction of 100-300 calories per day.

RESULTS

The HB experienced a greater weight loss in the first 6 months (-1.4 vs. -0.8 kg; p=0.04), but after 12 months there was no differences between groups (-1.1 vs. -1.0; p=0.20). Of the serum biochemical markers, HDL cholesterol showed major change, with an increase at month 12 of 18.3mg/dl in the HB compared to 9.5 in the CG (p<0.01).

CONCLUSION

Home-based exercise promoted greater weight reduction during the first 6 months after which no further benefits are observed. Continuous favorable changes in HDL cholesterol after 1 year suggest that home-based exercise promote health benefits.

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.

Physical activity, obesity and cardiometabolic risk factors in 9- to 10-year-old UK children of white European, South Asian and black African-Caribbean origin: the Child Heart And health Study in England (CHASE)

AIMS/HYPOTHESIS

Physical inactivity is implicated in unfavourable patterns of obesity and cardiometabolic risk in childhood. However, few studies have quantified these associations using objective physical activity measurements in children from different ethnic groups. We examined these associations in UK children of South Asian, black African-Caribbean and white European origin.

METHODS

This was a cross-sectional study of 2,049 primary school children in three UK cities, who had standardised anthropometric measurements, provided fasting blood samples and wore activity monitors for up to 7 days. Data were analysed using multilevel linear regression and allowing for measurement error.

RESULTS

Overall physical activity levels showed strong inverse graded associations with adiposity markers (particularly sum of skinfold thicknesses), fasting insulin, HOMA insulin resistance, triacylglycerol and C-reactive protein; for an increase of 100 counts of physical activity per min of registered time, levels of these factors were 12.2% (95% CI 10.2-14.1%), 10.2% (95% CI 7.5-12.8%), 10.2% (95% CI 7.5-12.8%), 5.8% (95% CI 4.0-7.5%) and 19.2% (95% CI 13.9-24.2%) lower, respectively. Similar increments in physical activity levels were associated with lower diastolic blood pressure (1.0 mmHg, 95% CI 0.6-1.5 mmHg) and LDL-cholesterol (0.04 mmol/l, 95% CI 0.01-0.07 mmol/l), and higher HDL-cholesterol (0.02 mmol/l, 95% CI 0.01-0.04 mmol/l). Moreover, associations were broadly similar in strength in all ethnic groups. All associations between physical activity and cardiometabolic risk factors were reduced (albeit variably) after adjustment for adiposity.

CONCLUSIONS/INTERPRETATION

Objectively measured physical activity correlates at least as well with obesity and cardiometabolic risk factors in South Asian and African-Caribbean children as in white European children, suggesting that efforts to increase activity levels in such groups would have equally beneficial effects.

Dietary factors related to body weight in adult Vietnamese in the rural area of Haiphong, Vietnam: the Korean Genome and Epidemiology Study (KoGES)

The objectives of this study were to examine the association between dietary factors and underweight and overweight adult Vietnamese living in the rural areas of Vietnam. A cross-sectional study of 497 Vietnamese aged 19 to 60 years (204 males, 293 females) was conducted in rural areas of Haiphong, Vietnam. The subjects were classified as underweight, normal weight, and overweight based on BMI. General characteristics, anthropometric parameters, blood profiles, and eating habits were obtained and dietary intake was assessed using 24-hour recalls for 2 consecutive days. A high prevalence of both underweight (BMI < 18.5 kg/m(2)) and overweight (BMI >/= 23 kg/m(2)) individuals was observed (14.2% and 21.6% for males and 18.9% and 20.6% for females, respectively). For both genders, the overweight group were older than the under- and normal weight groups (P = 0.0118 for males and P = 0.0002 for females). In female subjects, the overweight group consumed significantly less cereals (P = 0.0033), energy (P = 0.0046), protein (P = 0.0222), and carbohydrate (P = 0.0017) and more fruits (P = 0.0026) than the underweight group; however, no such differences existed in males. The overweight subjects overate more frequently (P = 0.0295) and consumed fish (P = 0.0096) and fruits (P = 0.0083) more often. The prevalence of both underweight and overweight individuals pose serious public health problems in the rural areas of Vietnamese and the overweight group was related to overeating and high fish and fruit consumption. These findings may provide basic data for policymakers and dieticians in order to develop future nutrition and health programs for rural populations in Vietnam.

Exercise-induced energy expenditure: implications for exercise prescription and obesity

OBJECTIVE

Walking is commonly recommended to help with weight management. We measured total energy expenditure (TEE) and its components to quantify the impact of increasing exercise-induced energy expenditure (ExEE) on other components of TEE.

METHODS

Thirteen obese women underwent an 8-week walking group intervention. TEE was quantified using doubly labeled water, ExEE was quantified using heart rate monitors, daily movement was assessed by accelerometry and resting metabolic rate was measured using indirect calorimetry.

RESULTS

Four of the 13 participants achieved the target of 1500kcalwk(-1) of ExEE and all achieved 1000kcalwk(-1). The average ExEE achieved by the group across the 8 weeks was 1434+/-237kcalwk(-1). Vigorous physical activity, as assessed by accelerometry, increased during the intervention by an average of 30min per day. Non-exercise activity thermogenesis (NEAT) decreased, on average, by 175kcald(-1) (-22%) from baseline to the intervention and baseline fitness was correlated with change in NEAT.

CONCLUSIONS

Potential alterations in non-exercise activity should be considered when exercise is prescribed. The provision of appropriate education on how to self-monitor daily activity levels may improve intervention outcomes in groups who are new to exercise.

PRACTICE IMPLICATIONS

Strategies to sustain incidental and light physical activity should be offered to help empower individuals as they develop and maintain healthy and long-lasting lifestyle habits.