The role of physical activity in prevention and treatment of body weight gain in adults

Comprehensive Genetic Analysis of Associations between Obesity-Related Parameters and Physical Activity: A Scoping Review

Genetic epidemiological studies have shown that numerous genetic variants cumulatively increase obesity risk. Although genetically predisposed individuals are more prone to developing obesity, it has been shown that physical activity can modify the genetic predisposition to obesity. Therefore, genetic data obtained from earlier studies, including 30 polymorphisms located in 18 genes, were analyzed using novel methods such as the total genetic score and Biofilter 2.4 software to combine genotypic and phenotypic information for nine obesity-related traits measured before and after the realization of the 12-week training program. The results revealed six genes whose genotypes were most important for post-training changes-LEP, LEPR, ADIPOQ, ADRA2A, ADRB3, and DRD2. Five noteworthy pairwise interactions, LEP × LEPR, ADRB2 × ADRB3, ADRA2A × ADRB3, ADRA2A × ADRB2, ADRA2A × DRD2, and three specific interactions demonstrating significant associations with key parameters crucial for health, total cholesterol (TC), high-density lipoprotein (HDL), and fat-free mass (FFM), were also identified. The molecular basis of training adaptation described in this study would have an enormous impact on the individualization of training programs, which, designed according to a given person's genetic profile, will be effective and safe intervention strategies for preventing obesity and improving health.

Exercise restores brain insulin sensitivity in sedentary adults who are overweight and obese

BACKGROUNDInsulin resistance of the brain can unfavorably affect long-term weight maintenance and body fat distribution. Little is known if and how brain insulin sensitivity can be restored in humans. We aimed to evaluate the effects of an exercise intervention on insulin sensitivity of the brain and how this relates to exercise-induced changes in whole-body metabolism and behavior.METHODSIn this clinical trial, sedentary participants who were overweight and obese underwent an 8-week supervised aerobic training intervention. Brain insulin sensitivity was assessed in 21 participants (14 women, 7 men; age range 21-59 years; BMI range 27.5-45.5 kg/m2) using functional MRI, combined with intranasal administration of insulin, before and after the intervention.RESULTSThe exercise program resulted in enhanced brain insulin action to the level of a person of healthy weight, demonstrated by increased insulin-induced striatal activity and strengthened hippocampal functional connectivity. Improved brain insulin action correlated with increased mitochondrial respiration in skeletal muscle, reductions in visceral fat and hunger, as well as improved cognition. Mediation analyses suggest that improved brain insulin responsiveness helps mediate the peripheral exercise effects leading to healthier body fat distribution and reduced perception of hunger.CONCLUSIONOur study demonstrates that an 8-week exercise intervention in sedentary individuals can restore insulin action in the brain. Hence, the ameliorating benefits of exercise toward brain insulin resistance may provide an objective therapeutic target in humans in the challenge to reduce diabetes risk factors.TRIAL REGISTRATIONClinicalTrials.gov (NCT03151590).FUNDINGBMBF/DZD 01GI0925.

Effects of Coenzyme Q10 Supplementation on Anthropometric Indices in Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background:

Obesity is related to increase in the incidence of morbidity and mortality. Previous studies have led to conflicting results regarding the effect of coenzyme Q10 (CoQ10) supplementation on anthropometric indices. This study aimed to evaluate the efficacy of CoQ10 supplementation on body weight, body mass index (BMI), and waist circumference (WC) through a systematic review and meta-analysis of randomized controlled trials (RCTs).

Methods:

PubMed, Scopus, Web of Science, and Cochrane Library as well as the reference lists of the identified relevant RCTs were searched up to March 2019, and weighted mean differences (WMDs) were pooled by using the random-effects model.

Results:

Twenty RCTs (976 participants) were eligible to be included in the systematic review. The meta-analysis revealed that CoQ10 supplementation had no effect on body weight (WMD = −0.04 kg; 95% confidence interval [CI]: −1.96, 1.6; I² = 0.0%), BMI (WMD = −0.06 kg/m²; 95% CI: −0.54, 0.42; I² = 0.0%), and WC (WMD = 0.79 cm; 95% CI: −2.83, 0.04; I² = 0.0%).

Conclusions:

CoQ10 supplementation might not improve anthropometric indices. Future well-designed trials are still needed to confirm these results.

Commonalities in Management and Husbandry Factors Important for Health and Welfare of Captive Elephants in North America and Thailand

Abstract: This review paper is a synthesis of results from multiple studies that we have conducted over the past several years using similar methodologies to identify factors related to welfare of captive populations of elephants in North American zoos and Thailand tourist camps. Using multiple conservation physiology tools, we found that, despite vastly disparate management systems, there are commonalities in how environmental and husbandry factors affect physical and physiological outcomes. Elephants appear to have better welfare, based on fecal glucocorticoid metabolite (FGM) analyses, when housed under conditions that provide a more enriched, stimulating, and less restrictive environment. We also found it is essential to balance diet and exercise for good body condition and metabolic function. In Thailand, use of tools to control elephants, such as the ankus (i.e., guide, hook) and chains, did not equate to poor welfare per se, nor did riding; however, improper uses were associated with higher wound scores and FGM concentrations. Foot health was good overall in both regions, with cracks being the most common problem, and better foot scores were found in elephants kept on softer substrates. Based on these findings, science-based guidelines are being developed in Thailand, while in North America, changes are being incorporated into elephant standards and husbandry resource guides. Management across venues can be improved by encouraging elephant exploration and exercise, establishing socially compatibility groups, ensuring proper use of tools, and providing balanced diets. We contend there is no "one-size-fits-all" management strategy to guarantee good welfare for elephants, but there are essential needs that must be met regardless of where or how they are managed. Future studies are needed to find ways to better socialize elephants; determine how temperament affects coping styles and resilience; study the importance of good handler-elephant relationships; identify more ways for elephants to engage with the environment; and assess the effect of life history on subsequent physiological and psychological well-being.

Perceived barriers to physical activity during and after a behavioural weight loss programme

BACKGROUND

Most adults with overweight/obesity participating in behavioural weight loss (BWL) programmes never achieve prescribed physical activity (PA) levels. This study examined changes in PA barriers, their relationships with accelerometer-measured PA during and after a 12-month BWL programme, and associations between PA barriers and participant characteristics.

METHODS

Adults (N = 283) in a BWL programme completed the Barriers to Being Active Quiz, a 21-item self-report measure that assesses seven perceived PA barriers, and they wore an accelerometer for seven consecutive days at baseline and at 6 (midtreatment), 12 (end of treatment), 18 (6-mo follow-up), and 24 months (12-mo follow-up). Weight and height were measured, and demographic information was collected at baseline.

RESULTS

Repeated-measures analyses of variance (ANOVAs) revealed a significant quadratic effect of time on total PA barriers, P < .001, such that PA barriers decreased by midtreatment, remained below baseline levels by end of treatment, but increased to near-baseline levels by follow-up. Perceived PA barriers were negatively associated with baseline moderate-to-vigorous PA (MVPA), P < .001, and decreases in perceived PA barriers were related to greater MVPA at 6 (P = .004), 12 (P < .001), and 24 months (P = .007). Participants who were younger, P = .02, and white, P = .009, reported more baseline barriers.

CONCLUSIONS

Perceived PA barriers meaningfully decreased during BWL treatment, which in turn was associated with greater MVPA. This pattern suggests that, on average, BWL effectively addresses perceived PA barriers, which contributes to increased PA. Future research should identify interventions to maintain decreases in barriers after end of treatment.

WHOLE-BODY VIBRATION TRAINING PROTOCOLS IN OBESE INDIVIDUALS: A SYSTEMATIC REVIEW

ABSTRACT Obesity is a chronic degenerative disease. Whole-body vibration (WBV) devices make it possible to control the intensity of exercises through their variables: frequency, amplitude and vibration time, thus enabling interventions in these populations. The objective of this study was to review the applications, protocols and results of WBV devices in obese individuals. A systematic literature review was conducted using the descriptors and terms verified in DeCS (LILACS and SCIELO) and MeSH (PubMED). Of the thirteen studies selected, seven used an experimental and six a quasi-experimental methodological design. Eleven studies analyzed chronic responses and two studies acute responses to WBV training. Frequency values ranged between 30 and 35 Hz, amplitude was around 2 mm, and in terms of intensity, most of the training protocols used a gradual increase in WBV throughout the intervention. Eight studies added dynamic exercises and extra loads to the WBV. The mean total WBV exposure time varied around 20’ distributed in 1 or 2 series, with vibration times of 30” to 60” and the same rest time. The mean frequency of interventions was around 2 to 3 times a week, with a mean intervention time of 10 months. The main results include: decrease in body weight and improvement in the physiological variables of oxygen absorption, bone mineral density and arterial profile, indicating that WBV can be a safe tool in the fight against obesity and its implications. Level of Evidence II. Systematic Review of Level II Studies.

Effects of Physical Activity and Sedentary Behavior on Brain Response to High-Calorie Food Cues in Young Adults

OBJECTIVE

Physical activity (PA) promotes weight maintenance, potentially because of its beneficial effects on feeding behavior regulation via diminished food cue reactivity within brain reward regions. This study examined how levels of PA and sedentary behavior (SB) relate to brain responses to food cues.

METHODS

Participants (22 lean, 18 with obesity) completed three to five PA recalls over 2 months. Average minutes per day of moderate to vigorous PA (MVPA) and SB were calculated. Participants completed a functional magnetic resonance imaging session, viewing food and nonfood images following glucose ingestion. Region of interest (ROI) analysis examined associations between MVPA and brain percent signal change in response to food versus nonfood images, controlling for obesity and sex. Secondary analysis examined associations between SB and brain responses to food cues.

RESULTS

Greater MVPA was associated with decreased food cue reactivity after glucose across brain ROIs (β = -0.00057, P = 0.005), controlling for obesity and sex. Greater SB was associated with increased food cue reactivity after glucose across brain ROIs in unadjusted analyses (β = 0.00041, P = 0.026).

CONCLUSIONS

PA may have beneficial effects on brain regulation of feeding behavior after caloric intake in lean individuals and individuals with obesity.

Building research in diet and cognition: The BRIDGE randomized controlled trial

Obesity has been linked to cognitive impairment, cognitive decline and dementia. Given that 38.5% of U.S. adults 60years and older are obese and these numbers are rapidly increasing, strategies to decouple obesity from cognitive decline are needed. Innovative lifestyle strategies that may postpone the onset of subclinical symptoms or even arrest the transition to overt dementia in at-risk individuals are critically needed. Poor diet is central to the development of obesity and diet may affect cognition. Adherence to a Mediterranean Diet (MedDiet) is associated with reduced risk of cognitive impairment and dementia. Furthermore, weight loss through caloric restriction improves cognitive function. This paper describes the Building Research in Diet and CoGnition (BRIDGE) study, a randomized trial examining the effect of the MedDiet, with and without weight loss, on cognitive functioning in obese older adults. Obese (BMI≥30 and ≤50kg/m2) older adults (≥55years) (n=180) will be randomized in a 2:2:1 allocation scheme to: Typical Diet Control; MedDiet alone, without weight loss; or MedDiet lifestyle intervention to promote weight loss and weight loss maintenance. Both MedDiet intervention groups will meet for one individual session and 27 group sessions over an 8-month period. Individuals in the control group will not receive instruction on changing lifestyle habits. Outcomes will be assessed at baseline, 8 and 14months. The primary outcome is cognitive functioning; secondary outcomes will include changes in body weight, diet, cardiovascular, metabolic, and inflammatory biomarkers.

The Effects of Food Labelling on Postexercise Energy Intake in Sedentary Women

Food labelling has been previously reported to influence energy intake (EI). Whether food labels influence postexercise EI remains to be determined. We assessed how food labelling and exercise (Ex) interact to influence food perception and postexercise EI. In this randomized crossover design, 14 inactive women participated in 4 experimental conditions: Ex (300 kcal at 70% of VO_2peak) and lunch labelled as low in fat (LF), Ex and lunch labelled as high in fat (HF), Rest and LF, and Rest and HF. The lunch was composed of a plate of pasta, yogurt, and oatmeal cookies, which had the same nutritional composition across the 4 experimental conditions. EI at lunch and for the 48-hour period covering the testing day and the following day was assessed. Furthermore, perceived healthiness of the meal and appetite ratings were evaluated. There were no effects of exercise and food labelling on EI. However, meals labelled as LF were perceived as heathier, and this label was associated with higher prospective food consumption. Initial beliefs about food items had a stronger effect on healthiness perception than the different food labels and explain the positive correlation with the amount of food consumed (ρ = 0.34, P < 0.001).

Assessment of Body Condition in African (Loxodonta africana) and Asian (Elephas maximus) Elephants in North American Zoos and Management Practices Associated with High Body Condition Scores

Obesity has a negative effect on health and welfare of many species, and has been speculated to be a problem for zoo elephants. To address this concern, we assessed the body condition of 240 elephants housed in North American zoos based on a set of standardized photographs using a 5-point Body Condition Score index (1 = thinnest; 5 = fattest). A multi-variable regression analysis was then used to determine how demographic, management, housing, and social factors were associated with an elevated body condition score in 132 African (Loxodonta africana) and 108 Asian (Elephas maximus) elephants. The highest BCS of 5, suggestive of obesity, was observed in 34% of zoo elephants. In both species, the majority of elephants had elevated BCS, with 74% in the BCS 4 (40%) and 5 (34%) categories. Only 22% of elephants had BCS 3, and less than 5% of the population was assigned the lowest BCS categories (BCS 1 and 2). The strongest multi-variable model demonstrated that staff-directed walking exercise of 14 hours or more per week and highly unpredictable feeding schedules were associated with decreased risk of BCS 4 or 5, while increased diversity in feeding methods and being female was associated with increased risk of BCS 4 or 5. Our data suggest that high body condition is prevalent among North American zoo elephants, and management strategies that help prevent and mitigate obesity may lead to improvements in welfare of zoo elephants.

Managing diabetes in the digital age

The prevalence of diabetes is rising globally. Poor glucose control results in higher rates of diabetes-related complications and an increase in health care expenditure. Diabetes self-management education (DSME) training has shown to improve glucose control, and thus may reduce long-term complications. Implementation of diabetes self-management education programs may not be feasible for all the institutions or in developing countries due to lack of resources and higher costs associated with DSME training. With the increasing use of smartphones and Internet, there is an opportunity to use digital tools for training people with diabetes to self-manage their disease. A number of mobile applications, Internet portal, and websites are available to help patients to improve their diabetes care. However, the studies are limited to show its effectiveness and cost-benefits in diabetes self-management. In addition, there are many challenges ahead for the digital health industry. In this review, we assess the use of newer technologies and digital health in diabetes self-management with a focus on future directions and potential challenges.

Attentional distraction during exercise in overweight and normal-weight boys

The purpose of this study was to investigate the effect of attentional distraction on field running distance and activity intensity during an exercise session in normal-weight and overweight youngsters and to investigate potential mediators. Fifty-three 12–14 yr-old boys participated twice in a 12-min running test and a 20-min exercise session, once with attentional distraction (by listerning to music) and once without distraction (counterbalanced randomised controlled design). At the end of the endurance test running distance was recorded. During the exercise session activity intensity was assessed by accelerometers. After each experiment, rate of perceived exertion (RPE) was estimated and seven questions were asked about how participants experienced the experiment. Both overweight and normal-weight boys ran further during the running test with music (p < 0.05) and this effect was mediated by a decrease in feelings of annoyance. During the exercise session with music, both overweight and normal-weight boys exercised less at low and high intensity and more at moderate and very high intensity (p < 0.01) and this effect was mediated by a decrease in RPE. We can conclude that attentional distraction has a positive effect on running distance on a field endurance test and on activity intensity during an exercise session through different mechanisms in both overweight and normal-weight boys.

Effectiveness of a physical activity and weight loss intervention for middle-aged women: healthy bodies, healthy hearts randomized trial

BACKGROUND

Physical inactivity is a significant risk factor for cardiovascular disease and remains highly prevalent in middle-aged women.

OBJECTIVE

We hypothesized that an interventionist-led (IL), primary-care-based physical activity (PA) and weight loss intervention would increase PA levels and decrease weight to a greater degree than a self-guided (SG) program.

DESIGN

We conducted a randomized trial.

PARTICIPANTS

Ninety-nine inactive women aged 45-65 years and with BMI ≥ 25 kg/m(2) were recruited from three primary care clinics.

INTERVENTIONS

The interventionist-led (IL) group (n = 49) had 12 weekly sessions of 30 min discussions with 30 min of moderate-intensity PA. The self-guided (SG) group (n = 50) received a manual for independent use.

MAIN MEASURES

Assessments were conducted at 0, 3, and 12 months; PA and weight were primary outcomes. Weight was measured with a standardized protocol. Leisure PA levels were assessed using the Modifiable Activity Questionnaire. Differences in changes by group were analyzed with a t-test or Wilcoxon rank-sum test. Mixed models were used to analyze differences in changes of outcomes by group, using an intention-to-treat principle.

KEY RESULTS

Data from 98 women were available for analysis. At baseline, mean (SD) age was 53.9 (5.4) years and 37 % were black. Mean weight was 92.3 (17.7) kg and mean BMI was 34.7 (5.9) kg/m(2). Median PA level was 2.8 metabolic equivalent hours per week (MET-hour/week) (IQR 0.0, 12.0). At 3 months, IL women had a significantly greater increase in PA levels (7.5 vs. 1.9 MET-hour/week; p = 0.02) than SG women; there was no significant difference in weight change. At 12 months, the difference between groups was no longer significant (4.7 vs. 0.7 MET-hour/week; p = 0.38). Mixed model analysis showed a significant (p = 0.048) difference in PA change between groups at 3 months only.

CONCLUSIONS

The IL intervention was successful in increasing the physical activity levels of obese, inactive middle-aged women in the short-term. No significant changes in weight were observed.

Physical activity after surgically obtained weight loss: study with a SenseWear armband in subjects undergoing biliopancreatic diversion

BACKGROUND

This study aimed to understand the role of the extra load of body mass in limiting physical activity and in preventing an active lifestyle in severely obese patients.

MATERIALS AND METHODS

The study was carried out in a University Hospital setting, and investigates severely obese patients, having undergone biliopancreatic diversion (BPD) for obesity and control subjects with a body weight closely similar to that of the BPD subjects; energy intake was evaluated by alimentary interview and energy expenditure was assessed with the Body Media SenseWear® Pro armband (SWA).

RESULTS

SWA metabolic efficiency (MET) was negatively associated with body mass index values (ρ = -0.464, p < 0.01), and the SWA overall energy expenditure was very similar to the energy alimentary intake in the obese patients and in the control subjects. Among the controls, the MET mean value was higher (p < 0.05) than that observed both in obese and in BPD subjects (1.392 ± 0.211 vs. 1.149 ± 0.181 and 1.252 ± 0.284, respectively); furthermore, in comparison with the obese and the BPD groups, among the control individuals a greater number of active persons (27% vs. 0 and 7%, respectively) and a lower number of sedentary persons (27% vs. 70 and 43%, respectively) was found (p < 0.01).

CONCLUSIONS

These preliminary results suggest the reliability of SWA data in assessing energy expenditure and tend to rule out the hypothesis that in severely obese patients the extra load of body mass by itself is a main factor limiting physical activity and leading to a sedentary lifestyle.

Use of quantile regression to investigate the longitudinal association between physical activity and body mass index

OBJECTIVE

To examine associations among age, physical activity (PA), and birth cohort on body mass index (BMI) percentiles in men.

METHODS

Longitudinal analyses using quantile regression were conducted among men with ≥ two examinations between 1970 and 2006 from the Aerobics Center Longitudinal Study (n = 17,759). Height and weight were measured; men reported their PA and were categorized as inactive, moderately, or highly active at each visit. Analyses allowed for longitudinal changes in PA.

RESULTS

BMI was greater in older than younger men and in those born in 1960 than those born in 1940. Inactive men gained weight significantly more rapidly than active men. At the 10th percentile, increases in BMI among inactive, moderately active, and highly active men were 0.092, 0.078, and 0.069 kg/m(2) per year of age, respectively. The 10th percentile increased by 0.081 kg/m(2) per birth year and by 0.180 kg/m(2) at the 90th percentile, controlling for age.

CONCLUSION

Although BMI increased with age, PA reduced the magnitude of the gradient among active compared to inactive men. Regular PA had an important, protective effect against weight gain. This study provides evidence of the utility of quantile regression to examine the specific causes of the obesity epidemic.

Comparison of traditional versus mobile app self-monitoring of physical activity and dietary intake among overweight adults participating in an mHealth weight loss program

OBJECTIVE

Self-monitoring of physical activity (PA) and diet are key components of behavioral weight loss programs. The purpose of this study was to assess the relationship between diet (mobile app, website, or paper journal) and PA (mobile app vs no mobile app) self-monitoring and dietary and PA behaviors.

MATERIALS AND METHODS

This study is a post hoc analysis of a 6-month randomized weight loss trial among 96 overweight men and women (body mass index (BMI) 25-45 kg/m(2)) conducted from 2010 to 2011. Participants in both randomized groups were collapsed and categorized by their chosen self-monitoring method for diet and PA. All participants received a behavioral weight loss intervention delivered via podcast and were encouraged to self-monitor dietary intake and PA.

RESULTS

Adjusting for randomized group and demographics, PA app users self-monitored exercise more frequently over the 6-month study (2.6±0.5 days/week) and reported greater intentional PA (196.4±45.9 kcal/day) than non-app users (1.2±0.5 days/week PA self-monitoring, p<0.01; 100.9±45.1 kcal/day intentional PA, p=0.02). PA app users also had a significantly lower BMI at 6 months (31.5±0.5 kg/m(2)) than non-users (32.5±0.5 kg/m(2); p=0.02). Frequency of self-monitoring did not differ by diet self-monitoring method (p=0.63); however, app users consumed less energy (1437±188 kcal/day) than paper journal users (2049±175 kcal/day; p=0.01) at 6 months. BMI did not differ among the three diet monitoring methods (p=0.20).

CONCLUSIONS

These findings point to potential benefits of mobile monitoring methods during behavioral weight loss trials. Future studies should examine ways to predict which self-monitoring method works best for an individual to increase adherence.

Veteran Status and Body Weight: A Longitudinal Fixed-Effects Approach

About 10-12 % of young men (and increasingly, women) have served a term in the military. Yet, we know relatively little about the consequences of military service for the lives of those who serve. In this article, we provide estimates of the relationship between men's peacetime military service during the all-volunteer era (AVE) and body weight using longitudinal data on 6,304 men taken from the National Longitudinal Survey of 1979 (NLSY-79). Using fixed-effects estimators on up to 13 years of data and numerous controls for time-varying life-course characteristics linked to body weight, we find that veterans of active-duty military service have higher levels of BMI and obesity. We argue that eating habits learned during service, coupled with patterns of physical activity, lead to a situation whereby veterans making the transition to less active civilian lifestyles gain weight that is not lost over time.

Physical activity and physical function in individuals post-bariatric surgery

BACKGROUND

A better understanding of the physical activity behavior of individuals who undergo bariatric surgery will enable the development of effective post-surgical exercise guidelines and interventions to enhance weight loss outcomes. This study characterized the physical activity profile and physical function of 40 subjects 2-5 years post-bariatric surgery and examined the association between physical activity, physical function, and weight loss after surgery.

METHODS

Moderate-to-vigorous intensity physical activity (MVPA) was assessed with the BodyMedia SenseWear® Pro (SWPro) armband, and physical function (PF) was measured using the physical function subscale of the 36-Item Short Form Health Survey instrument (SF-36(PF)). Height and weight were measured.

RESULTS

Percent of excess weight loss (%EWL) was associated with MVPA (r = 0.44, p = 0.01) and PF (r = 0.38, p = 0.02); MVPA was not associated with PF (r = 0.24, p = 0.14). Regression analysis demonstrated that MVPA was associated with %EWL (β = 0.38, t = 2.43, p = 0.02). Subjects who participated in ≥150 min/week of MVPA had a greater %EWL (68.2 ± 19, p = 0.01) than those who participated in <150 min/week (52.5 ± 17.4).

CONCLUSIONS

Results suggest that subjects are capable of performing most mobility activities. However, the lack of an association between PF and MVPA suggests that a higher level of PF does not necessarily correspond to a higher level of MVPA participation. Thus, the barriers to adoption of a more physically active lifestyle may not be fully explained by the subjects' physical limitations. Further understanding of this relationship is needed for the development of post-surgical weight loss guidelines and interventions.

How to make overweight children exercise and follow the recommendations

As regular physical activity of high enough intensity is essential in the management of overweight, efforts should be made to increase physical activity adherence in overweight children. To make overweight children exercise and follow the recommendations, it is essential to have insight into determinants of exercise initiation and adherence. According to the Self-determination Theory, creating opportunities to satisfy the need for autonomy (i.e., having choices), competence (i.e., feeling effective) and relatedness (i.e., being socially connected) might increase autonomous motivation for physical activity in overweight children and promote a long-lasting active lifestyle. To increase feelings of autonomy in overweight children, exercise programs could be delivered in an autonomy-supportive manner by providing choices, supporting the child's initiatives, avoiding use of external rewards, offering relevant information and rationale for changing behaviour, making a decisional balance and using autonomy supportive language, while minimizing pressure and control. Perceived competence in physical activities could be increased by offering activities tailored to the capabilities of the overweight child, helping the children set realistic goals, learning the children self-management skills, providing the children with appropriate feedback and organizing separate exercise sessions for overweight children. Feelings of relatedness in overweight children might increase by adopting an empathic approach, showing interest in the child's well-being and problems, showing enjoyment and enthusiasm, knowing the names of the children, talking to the children as equals, offering group sessions and talks, encouraging club participation and having a sports partner and encouraging parental support.

The effects of exercise on the neuronal response to food cues

Increased physical activity is associated with successful long-term weight loss maintenance due to mechanisms likely more complex than simply increased energy expenditure. The impact of physical activity on the central regulation of food intake may be an important mechanism of this effect. The objective of this study was to examine the effects of exercise training and acute exercise on the neuronal response to food cues as well as eating behaviors. fMRI was performed in the fasted state at baseline and again after a 6 month progressive exercise intervention (supervised, 5 days/wk) both with and without an acute exercise bout in 12 overweight/obese (5 women, 7 men; BMI 33 ± 4 kg/m(2)) healthy adults. fMRI data were acquired while subjects were presented with visual stimuli of foods of high hedonic value as compared to neutral control objects. Questionnaires on eating behaviors, ratings of appeal and desire for foods, and ratings of appetite (hunger, satiety, prospective intake) using visual analog scales were also performed at baseline and again after the 6-month exercise intervention. While only a trend was observed for a reduction in body weight (102 ± 5 to 99 ± 6 kg, p=0.09), a significant reduction in fat mass was observed (36.4 ± 2.8 to 33.7 ± 3.2 kg, p=0.04), although as expected changes in fat mass were variable (-10.0 to +3.7 kg). Chronic exercise was associated with a reduction in the neuronal response to food, primarily in the posterior attention network and insula. A significant positive correlation between the change in fat/body mass and the change in insula response to food cues with chronic exercise was observed. An acute exercise bout attenuated the effects of chronic exercise. The exercise intervention, however, did not impact any of the measures of appetitive behavior. In summary, despite no effects on behavioral measures of appetite, chronic exercise training was associated with attenuation in the response to visual food cues in brain regions known to be important in food intake regulation. The insula, in particular, appears to play an important role in the potential exercise-induced weight loss and weight loss maintenance.

Walk-run transition speed training as an efficient exercise adjunct to dietary restriction in the management of obesity: a prospective intervention pilot study

OBJECTIVE

The aim of this study was to test the utility of preferred walk-run transition speed (WRTS) in exercise training adjunct to dietary restriction for obesity management in healthy obese women.

MATERIALS AND METHODS

37 obese women (age: 35 ± 9 years, body mass index (BMI): 34.9 ± 4.6 kg/m(2)) were assigned to an intervention pilot study during 6 months of restricted diet alone (RD) followed by 6 months of RD combined with WRTS (RD and WRTS) as a training exercise. Body mass, waist circumference (WC), fat mass (FM), fat free mass (FFM), active cell mass (ACM), fasting glucose, serum lipids (triacylglycerol (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), apo-lipoproteins A1 (ApoA1) and B (ApoB)], leptin and insulin concentrations, and HOMA-IR were assessed at baseline (T0), at the end of the RD alone (T1), and at the end of the RD and WRTS programme (T2).

RESULTS

Mean weight loss was 8.6 ± 4.9 kg and 2.2 ± 2.9 kg for (T0-T1) and (T1-T2), respectively. Significant BMI and WC reductions were reported at T1 and T2. FM decreased significantly both with RD and with RD and WRTS training whereas FFM and ACM increased with RD and WRTS training only. TG decreased significantly with the two phases of the programme. A significant increase in HDL-C, and a decrease in LDL-C and TC/HDL-C ratio were noticed with RD and WRTS training. Heart rate monitored in training improved significantly after RD and WRTS training. A significant relationship (r = 0.542, p < 0.02) was demonstrated between reductions in serum leptin and insulin concentrations observed with both RD and WRTS training.

CONCLUSION

The addition of WRTS training to RD promoted a greater reduction in body mass, WC, FM, leptin and insulin concentrations, improved metabolic and cardiovascular risk factors, and enhanced cardiovascular fitness.

Self-monitoring in weight loss: a systematic review of the literature

Self-monitoring is the centerpiece of behavioral weight loss intervention programs. This article presents a systematic review of the literature on three components of self-monitoring in behavioral weight loss studies: diet, exercise, and self-weighing. This review included articles that were published between 1993 and 2009 that reported on the relationship between weight loss and these self-monitoring strategies. Of the 22 studies identified, 15 focused on dietary self-monitoring, one on self-monitoring exercise, and six on self-weighing. A wide array of methods was used to perform self-monitoring; the paper diary was used most often. Adherence to self-monitoring was reported most frequently as the number of diaries completed or the frequency of log-ins or reported weights. The use of technology, which included the Internet, personal digital assistants, and electronic digital scales were reported in five studies. Descriptive designs were used in the earlier studies whereas more recent reports involved prospective studies and randomized trials that examined the effect of self-monitoring on weight loss. A significant association between self-monitoring and weight loss was consistently found; however, the level of evidence was weak because of methodologic limitations. The most significant limitations of the reviewed studies were the homogenous samples and reliance on self-report. In all but two studies, the samples were predominantly white and women. This review highlights the need for studies in more diverse populations, for objective measures of adherence to self-monitoring, and for studies that establish the required dose of self-monitoring for successful outcomes.

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.

Obesogenic diet and physical activity: independent or associated behaviours in adolescents?

OBJECTIVE

Associations between diet and physical activity may identify behaviours that could be changed together to prevent childhood obesity. The present study examines associations between physical activity and obesogenic dietary behaviours in a large UK adolescent cohort.

DESIGN

Cross-sectional analysis of a UK cohort. Adolescents aged 10-11 years completed three 1 d diet diaries. Average daily energy consumption, percentage energy from fat and carbohydrate, energy density and grams of fruit and vegetables were estimated. To assess physical activity participants wore an accelerometer for three or more days. Regression models were run by sex to examine the extent to which dietary variables predicted physical activity before and after controlling for pubertal status, maternal education and adiposity.

SETTING

The Avon Longitudinal Study of Parents and Children (ALSPAC), south-west England.

SUBJECTS

Adolescents who provided diet data at age 10 years and physical activity data at age 11 years.

RESULTS

Among boys, percentage energy from fat was consistently negatively associated with accelerometer-determined indicators of physical activity (standardized beta (beta) = -0.055 to -0.101, P < 0.05) while total energy (beta = 0.066 to 0.091, P < 0.05) and percentage energy from carbohydrate (beta = 0.054 to 0.106, P < 0.05) were positively associated before and after adjustment for confounders. For girls fruit and vegetable intake was consistently positively associated with physical activity (beta = 0.056 to 0.074, P < 0.005). However all associations were weak. Associations were broadly comparable when participants with non-plausible dietary reports were included or excluded from the analyses.

CONCLUSIONS

Obesogenic diet and physical activity behaviours were weakly associated, suggesting that interventions should focus on implementing strategies that are independently successful at changing diet or physical activity behaviours either separately or in combination.

Autonomic activity and glycemic homeostasis are maintained by precocious and low intensity training exercises in MSG-programmed obese mice

Current research employed electrical records from superior vagus and sympathetic nerve branch that supply fat retroperitoneal tissue (RS nerve) to investigate whether very moderate swim training in obese-programmed mice would change sympathetic and parasympathetic autonomic nervous system activities. Neonatal mice were treated with monosodium L: -glutamate (MSG), during their first 5 days of life, to induce obesity. Mice started training on weaning, comprising free swimming 3 days/week, 15 min/day for 10 weeks. After 12 h fasting, the nerve electrical signals of the 90-day-old mice were processed to obtain firing rates. Blood samples were collected to measure glucose and insulin levels. Adrenal catecholamine content was measured. MSG treatment caused obesity. Hyperglycemia and hyperinsulinemia in MSG-obese mice, without any change in food intake, were obtained. Vagus firing rates were higher in obese mice than those in lean ones. A decrease in RS nerve activity and lower adrenal catecholamine stores have been observed. Swimming normalized blood glucose and insulin levels and MSG-obesity onset was attenuated by exercise. Vagus activity from obese mice decreased, whereas RS nerve activity and adrenal catecholamine levels increased in trained ones. Results suggest that autonomic activity imbalance and metabolic dysfunctions observed in MSG-obese mice were inhibited by precocious and moderate exercise training.

Efeito de um programa de condicionamento físico no broncoespasmo induzido pelo exercício em mulheres obesas

O broncoespasmo induzido pelo exercício físico (BIE) é uma síndrome clínica caracterizada pelo estreitamento brônquico e ocorre mais frequentemente em indivíduos obesos. OBJETIVO: Avaliar o possível efeito de um programa de condicionamento físico em relação ao BIE em mulheres obesas. MÉTODOS: Trinta e duas mulheres foram divididas em três grupos: grupo A (obesidade ou sobrepeso + treinamento físico), grupo B (obesidade ou sobrepeso) e grupo C (controle). Foi aplicado um teste de caminhada de seis minutos antes e após um período de 12 semanas. O BIE foi verificado por meio de um monitor de pico de fluxo expiratório após a aplicação do teste de caminhada. Durante essas 12 semanas, para o grupo A um programa de atividade física foi conduzido três vezes por semana e cada sessão de 60 minutos foi composta por 10 minutos de alongamento, seguidos por 30 de exercícios aeróbios (50% da frequência cardíaca de reserva como intensidade), 15 de exercícios de força de baixa intensidade e cinco de relaxamento e alongamento. RESULTADOS: O programa de treinamento físico causou aumento significativo no pico de fluxo expiratório mínimo após o teste de esforço (pré: 379 ± 16l/min; pós: 405 ± 12l/min; p < 0,05) e reduziu em 50% (33% para 17%) a proporção de mulheres que apresentou BIE (p < 0,05). CONCLUSÃO: O programa de condicionamento físico de 12 semanas foi capaz de melhorar a função respiratória de mulheres obesas.

Cardiorespiratory fitness and sedentary lifestyle in the morbidly obese

BACKGROUND

Sedentary lifestyles and poor physical fitness are major contributors to the current obesity and cardiovascular disease pandemic.

HYPOTHESIS

Daily physical activity and cardiorespiratory fitness are correlated in morbidly obese individuals in their free-living environment.

METHODS

Ten morbidly obese participants continuously wore an activity sensor that measured caloric expenditure, minute-by-minute physical activity, and steps/day over a 72-h period. Following collection of the device data, structured cardiorespiratory fitness testing was performed on each subject.

RESULTS

Mean caloric expenditure for all individuals was 2,668+/-481 kcal/d. On average, subjects took 3,763+/-2,223 steps. On average 23 h and 51.6 min per d were spent sleeping or engaged in sedentary activity (<3 metabolic equivalents [METs]) and the remaining 8.4 min were spent in moderate activity (3-6 METs). Average peak VO2 was 16.8+/-4.7 mL/kg/min. Higher peak VO2 correlated with higher total caloric expenditure (TCE; r=0.628, p=0.05) and trended with higher steps/day (r=0.591, p=0.07).

CONCLUSIONS

Most morbidly obese participants in this study were markedly sedentary. These study results may provide important links between obesity, poor fitness, and cardiovascular disease.

Increasing the motivation for physical activity in obese patients

OBJECTIVE

In this randomized controlled study, a standardized motivation intervention was compared with a relaxation intervention with regard to its effectiveness in decreasing dropout rates and increasing physical activity in a sample of obese patients.

METHOD

Thirty-eight obese participants were randomly assigned to a one-session motivation or relaxation intervention. Thereafter, both groups participated in an 8-week aerobic program. Adherence, physical activity, motivational stage of change, and body mass index (BMI) were assessed during intervention and at 3- and 6-month follow-ups.

RESULTS

During the aerobic program, the motivation group showed significantly fewer dropouts but comparable adherence if only completers were considered. Moreover, their weekly minutes of physical activity increased over time before leveling off, whereas steady decreases were observed in the relaxation group. For motivational stage of change and BMI, no significant group differences were observed.

DISCUSSION

The importance and efficacy of motivational interventions in enhancing the high dropout rates in obesity treatment is underlined.

Obesity reduction black intervention trial (ORBIT): six-month results

The Obesity Reduction Black Intervention Trial (ORBIT) is a randomized controlled trial designed to assess the efficacy of a culturally proficient 6-month weight loss intervention followed by a 1-year maintenance intervention. This article describes the results of the 6-month weight loss intervention. Two hundred thirteen obese black women aged 30-65 years were randomized to the intervention group or a general health control group. The intervention consisted of a 6-month culturally adapted weight loss program that targeted changes in diet and physical activity patterns. Weight, dietary intake, and physical activity were measured at baseline and 6 months. A total of 198 women (93%) completed both the baseline and postintervention assessments. Women in the intervention group lost significantly more weight than women in the control group (P < 0.001). However, weight change was variable within the intervention group, with a maximum weight loss of 19.4% of initial body weight and a maximum weight gain of 6.4% of initial body weight. Women in the intervention group also showed significant improvements in fruit intake (P < 0.01), Healthy Eating Index score (P < 0.001), and moderate (P = 0.05), and vigorous (P < 0.001) physical activity compared to women in the control group. This study demonstrates that a culturally adapted program can successfully promote weight loss in obese black women. However, average weight loss was relatively modest, and weight change varied widely within the intervention group. Further research is needed in order to develop programs that will allow more black women to achieve their weight loss goals..

Cognitive and behavioral approaches in the treatment of obesity

Cognitive behavioral interventions have formed the cornerstone of obesity treatment for the past two decades. These techniques, often combined with diet and exercise strategies, have been shown to produce weight losses of sufficient magnitude so as to reduce health risks. Though success in producing short-term weight loss is improving, many factors, including a metabolic energy gap, continue to challenge long-term weight maintenance results. This article reviews the unique influence of cognitive, behavioral, and metabolic factors on weight loss and weight-loss maintenance, and how future treatment packages might be modified to improve long-term weight loss outcomes.

Population-based prevention of obesity: the need for comprehensive promotion of healthful eating, physical activity, and energy balance: a scientific statement from American Heart Association Council on Epidemiology and Prevention, Interdisciplinary Committee for Prevention (formerly the expert panel on population and prevention science)

Obesity is a major influence on the development and course of cardiovascular diseases and affects physical and social functioning and quality of life. The importance of effective interventions to reduce obesity and related health risks has increased in recent decades because the number of adults and children who are obese has reached epidemic proportions. To prevent the development of overweight and obesity throughout the life course, population-based strategies that improve social and physical environmental contexts for healthful eating and physical activity are essential. Population-based approaches to obesity prevention are complementary to clinical preventive strategies and also to treatment programs for those who are already obese. This American Heart Association scientific statement aims: 1) to raise awareness of the importance of undertaking population-based initiatives specifically geared to the prevention of excess weight gain in adults and children; 2) to describe considerations for undertaking obesity prevention overall and in key risk subgroups; 3) to differentiate environmental and policy approaches to obesity prevention from those used in clinical prevention and obesity treatment; 4) to identify potential targets of environmental and policy change using an ecological model that includes multiple layers of influences on eating and physical activity across multiple societal sectors; and 5) to highlight the spectrum of potentially relevant interventions and the nature of evidence needed to inform population-based approaches. The evidence-based experience for population-wide approaches to obesity prevention is highlighted.

Physical activity patterns in the National Weight Control Registry

OBJECTIVE

The National Weight Control Registry (NWCR) was established in 1993 to examine the characteristics of those who are successful at weight loss: individuals maintaining a 13.6-kg weight loss for >1 year. The size of the registry has increased substantially since the early descriptions of this group a decade ago. The purpose of this study was to describe in detail the weekly physical activity habits of NWCR members, to examine the relationship between amount of activity and demographic characteristics, and to determine if changes in activity parameters have occurred over time.

METHODS AND PROCEDURES

Participants were 887 men and 2,796 women who enrolled in the NWCR between 1993 and 2004. Physical activity was evaluated at registry entry using the Paffenbarger Physical Activity Questionnaire.

RESULTS

NWCR entrants report an average of 2,621 +/- 2,252 kcal/week in physical activity. There is considerable variability in the amount of activity reported: 25.3% report <1,000 kcal/week and 34.9% report >3,000 kcal/week. Activity level on registry entry is related to the magnitude but not the duration of weight loss. The amount of activity reported by men has decreased over time while no significant change was observed in women. Changes in the types of activities most frequently reported were also observed.

DISCUSSION

Overall, NWCR participants are an extremely physically active group. However, the amount of activity reported is highly variable, making it difficult to develop a single recommendation for the optimum amount of physical activity for weight loss maintenance. A better understanding of individual-specific determinants of how much activity is required for weight loss maintenance ought to be a high research priority.

Participation in 150 min/wk of moderate or higher intensity physical activity yields greater weight loss after gastric bypass surgery

BACKGROUND

The American College of Sports Medicine's position stand on weight loss and prevention of weight regain in adults has suggested that overweight adults should participate in a minimum of 150 min/wk of moderate intensity physical activity (PA). This study compared the 3-, 6-, and 12-month postoperative weight loss between gastric bypass surgery (GBS) patients who met or exceeded the recommended 150 min/wk of moderate or higher PA and those not meeting the recommendation.

METHODS

The self-administered short version of the International Physical Activity Questionnaire was used to assess moderate or higher intensity PA participation at 3 (n = 178), 6 (n = 128), and 12 months (n = 209) after GBS. The patients' height and body weight were obtained to determine the kilograms of weight lost, percentage of excess weight loss, body mass index change, and total weight loss percentage. The weight loss differences were analyzed using analysis of covariance at each point, with age and preoperative body mass index as covariates.

RESULTS

Patients reporting 150 min/wk of moderate or higher PA had significantly (P <.05) greater weight lost, percentage of excess weight loss, change in body mass index, and total weight loss percentage at 6 and 12 months postoperatively. The percentage of excess weight loss was 56.0% +/- 11.5% versus 50.5% +/- 11.6% and 67.4% +/- 14.3% versus 61.7% +/- 17.0% for the group meeting and not meeting the PA requirement at 6 and 12 months after GBS, respectively. No significant difference existed at 3 months after GBS.

CONCLUSION

Participation in a minimum of 150 min/wk of moderate or higher intensity PA was associated with greater postoperative weight loss at 6 and 12 months postoperatively. Patients should be encouraged to meet or exceed this recommendation until prospective, randomized studies have definitively established a link between PA and greater postoperative weight loss and maintenance.

Physical activity in the treatment of obesity: beyond body weight reduction

The prevalence of obesity is high and continues to increase. Obesity is a leading risk factor for premature mortality and numerous chronic health conditions. The role of physical activity as a treatment and (or) preventive strategy for combating obesity has been the subject of substantial research. Most of this research has focused solely on reductions in total body weight and (or) fat mass as the indicator of treatment success. Because the deposition of fat in the abdomen and nonadipose tissues of the liver and muscle plays a major role in the development of obesity-related health risk, these depots have emerged as alternative targets for obesity treatment. Absent from previous reviews is a detailed consideration of the influence of physical activity on these treatment outcomes. The purpose of this review is to evaluate the independent role of physical activity in the treatment of obesity in a broader context; that is, through its effects on abdominal obesity and liver and muscle fat, in addition to its established effects on body weight and (or) total fat mass. Consideration is also given to the utility of physical activity with minimal or no weight loss in the treatment of obesity.

The NHF-NRG In Balance-project: the application of Intervention Mapping in the development, implementation and evaluation of weight gain prevention at the worksite

Very few examples of theory-driven and systematically developed weight gain prevention interventions for adults have been described in the literature. The present paper systematically describes the development, implementation and evaluation framework of a weight gain prevention programme directed at young adults at the worksite, namely the NHF-NRG In Balance-project. It not only can be used as a guide to systematically develop weight gain prevention interventions, but also gives an overview of the current theoretical and empirical knowledge-base in the field of obesity prevention. The outline of the paper follows the Intervention Mapping protocol, which includes a systematic inventory of important health issues, their risk behaviours and determinants of these risk behaviours, and specification of the proximal objectives of the programme directed at both energy intake and energy expenditure. The objectives are translated into behaviour change methods and strategies, which are combined in a stepwise intervention programme, and used for a detailed evaluation plan (process and effect evaluation). The NHF-NRG In Balance-project combines mass media and individually tailored communications with worksite environmental changes to raise awareness, to motivate and to enable energy balance behaviour changes. A quasi-experimental pre-test-multiple post-test control group design was applied in 12 worksites (>500 employees).

Decision boundaries and receiver operating characteristic curves: New methods for determining accelerometer cutpoints

We propose and evaluate the utility of an alternative method (decision boundaries) for establishing physical activity intensity-related accelerometer cutpoints. Accelerometer data collected from seventy-six 11- to 14-year-old boys during controlled bouts of moderate- and vigorous-intensity field physical activities were assessed. Mean values and standard deviations for moderate- and vigorous-intensity activities were obtained and normal equivalents generated. The decision boundary (the point of intersection of overlapping distributions) was used to create a lower-bound vigorous-intensity cutpoint. Receiver operating characteristic (ROC) curves compared the sensitivity and specificity of the new cutpoint and mean values with the actual activity. There was a 96.5% probability that participants performing vigorous-intensity physical activity were accurately classified when using the decision boundary of 6700 counts per minute, in contrast to the 50% accurately classified when the mean value was used. Inspection of the empirical ROC curve indicated that the decision boundary provided the optimal threshold to distinguish between moderate and vigorous physical activity for this dataset. In conclusion, decision boundaries reduced the error associated with determining accelerometer threshold values. Applying these methods to accelerometer data collected in specific populations will improve the precision with which accelerometer thresholds can be identified.

Attitude toward physical activity in normal-weight, overweight and obese adolescents

PURPOSE

To investigate differences in physical activity and attitude toward physical activity in adolescents with different degrees of overweight and explore whether the prediction of physical activity by attitude is moderated by level of overweight.

METHODS

Subjects were divided into a normal-weight group (n = 37, 18.8 +/- 1.2 kg/m2), an overweight group (n = 28, 25.9 +/- 1.3 kg/m2), and an obese group (n = 24, 33.7 +/- 4.1 kg/m2). Mean age was 14.6 +/- 1.2 years, with 72% girls. Physical activity was estimated using the Baecke Questionnaire. Attitude was measured by assessing perceived benefits and barriers.

RESULTS

Participation in sports was higher in normal-weight compared with overweight (p < .05) and obese (p < .01) subjects. There was no difference in leisure-time physical activity between groups. Perceived benefits did not differ between groups, but normal-weight subjects perceived less barriers ('physical complaints', 'not being good at it', 'insecure about appearance', 'not liking it') than their overweight (p < .05) and obese (p < .001) counterparts. Obese adolescents had a less positive attitude compared with their normal-weight (p < .001) and overweight (p < .05) peers. Sport participation was significantly predicted by the perceived benefit 'pleasure' (p < .05) and by the perceived barrier 'not liking it' (p < .001), after taking into account level of overweight. The association between sport participation and attitude was not moderated by level of overweight.

CONCLUSIONS

This study demonstrates that overweight and obese adolescents show lower sport participation and have a less positive attitude toward physical activity. Interventions in youngsters with weight problems should try to increase participation in sports by making activities more fun and attractive for these youngsters.

PREFER study: a randomized clinical trial testing treatment preference and two dietary options in behavioral weight management--rationale, design and baseline characteristics

BACKGROUND

Obesity, a disorder associated with a myriad of comorbidities, is increasing at an alarming rate around the world. Given that pharmacotherapy has limited available options and that bariatric surgery is reserved for those who are morbidly obese or who have significant comorbidities, the most common approach to the treatment of obesity is standard behavioral treatment. This approach includes behavior modification related to eating and activity habits. The purpose of this paper is to describe the rationale, design, methods and baseline sample characteristics of a randomized controlled trial of a behavioral intervention in weight loss management, referred to as the PREFER study.

METHODS

The PREFER study, using a four-group design, includes: (1) a randomization scheme that permits participants to indicate a preferred dietary treatment approach, and (2) two dietary options, one of which is a lacto-ovo-vegetarian diet that has demonstrated potential for long-term adherence. The intervention (32 treatment sessions) is delivered over 12 months and is followed by a 6-month maintenance phase; final assessment occurs at 18 months.

RESULTS

We screened 932 individuals and randomized 197 to the study: Treatment Preference-Yes (n=84) and Treatment Preference-No (n=98). To maintain a balance across the four treatment groups, 15 subjects who preferred the standard diet had to be discarded from the Treatment Preference-Yes group. Retention at 18 months for the first of three cohorts was 82%.

CONCLUSIONS

The PREFER study is a single center study and is the first randomized controlled trial examining a lacto-ovo-vegetarian diet as part of weight loss treatment. The ethnically diverse sample includes males and females with a body mass index of 27 to 43. The study has the potential to make a contribution to understanding the role of treatment preference and the potential of a lacto-ovo-vegetarian diet for long-term weight loss.

Long-term weight gain prevention: a theoretically based Internet approach

BACKGROUND

A major focus of Healthy People 2010 is promoting weight management and physical activity because overweight, obesity, and a sedentary lifestyle are strongly associated with risk for heart disease and stroke, diabetes, cancers, and premature death.

METHODS

Prevalence data and a focused review of weight management and physical activity studies point to the long-term weight gain prevention in normal weight (21-25 BMI), overweight (25-29 BMI), and even moderate obese (30-34 BMI) people as one alternative to prioritizing weight loss in health behavior interventions. This is because on a population basis annual weight gain is small (approximately 0.8 kg/year) and preventing weight gain appears to require only an energy shift of about 100 cal/day either through a modest increase in physical activity and/or consuming slightly less calories to maintain an energy balance. A more dynamic use of social cognitive theory (SCT) for developing programs to maintain health behavior changes is emerging with some evidence of long-term maintenance. The high use of the Internet provides a vehicle to reach different population segments with readily accessible, SCT-tailored long-term programs. Research studies using the Internet with tailored SCT interventions have shown changes in nutrition practices, physical activity, and weight loss for up to a year.

CONCLUSIONS

One promising approach to weight gain prevention in population segments is the development and wide spread use of longer-term Internet programs using specific principles and procedures from SCT.

Post-treatment phone contact: a weight maintenance strategy in obese youngsters

This study investigated the effect of post-treatment phone contact on weight-loss maintenance and activity behaviour in obese youngsters. In all, 20 patients who completed a weight reduction program were randomly assigned to a 5-month maintenance programme (experimental) or control condition. Following the maintenance programme, patients sent a weekly activity diary to the therapist, who in turn phoned them biweekly to discuss their activities. Body weight, stature and physical activity were measured before and after the maintenance programme. The control group showed a continuous increase in overweight after initial treatment, while the experimental group showed a steep increase during the summer holidays (no intervention), but this increase slowed down during the maintenance programme (P<0.05). Moderate-to-high intensity activities increased during the maintenance programme in the experimental group, but decreased in the control group (P<0.001). In conclusion, post-treatment phone contact appears to have the potential to be an effective maintenance strategy in obese youngsters.

Strategies for Healthy Weight Loss: From Vitamin C to the Glycemic Response

America is experiencing a major obesity epidemic. The ramifications of this epidemic are immense since obesity is associated with chronic metabolic abnormalities such as insulin resistance, dyslipidemia, and heart disease. Reduced physical activity and/or increased energy intakes are important factors in this epidemic. Additionally, a genetic susceptibility to obesity is associated with gene polymorphisms affecting biochemical pathways that regulate fat oxidation, energy expenditure, or energy intake. However, these pathways are also impacted by specific foods and nutrients. Vitamin C status is inversely related to body mass. Individuals with adequate vitamin C status oxidize 30% more fat during a moderate exercise bout than individuals with low vitamin C status; thus, vitamin C depleted individuals may be more resistant to fat mass loss. Food choices can impact post-meal satiety and hunger. High-protein foods promote postprandial thermogenesis and greater satiety as compared to high-carbohydrate, low-fat foods; thus, diet regimens high in protein foods may improve diet compliance and diet effectiveness. Vinegar and peanut ingestion can reduce the glycemic effect of a meal, a phenomenon that has been related to satiety and reduced food consumption. Thus, the effectiveness of regular exercise and a prudent diet for weight loss may be enhanced by attention to specific diet details.

BMI from 3–6 y of age is predicted by TV viewing and physical activity, not diet

OBJECTIVE

To investigate whether, diet, physical activity, sedentary behavior or television (TV) viewing predicted body mass index (BMI) among 3-7-y-old children.

DESIGN

A triethnic cohort of 3-4-y-old children was followed for 3 y from 1986 to 1989.

MEASUREMENTS

BMI was assessed at the beginning and end of each measurement year. Heart rate monitoring and observation were used to assess physical activity. Diet (calories, % calories from fat and carbohydrate), sedentary behavior and TV viewing were assessed by direct observation in each year. A repeated measures regression analysis with year as a factor and BMI at the end of each year as dependent variables was run. Nonsignificant variables were removed in a stepwise backward deletion process and significant interactions graphed.

RESULTS

The interactions between minutes of TV viewing per hour and study year and minutes of physical activity per hour and study year were significant (P<0.05). There were also significant main effects for TV viewing, physical activity and BMI from the beginning of the study. The model accounted for 65% of the variance in BMI across the three study years. Plotting the significant interactions demonstrated that physical activity was positively associated with BMI in year 1, and negatively associated in years 2 and 3 with a stronger negative relationship in year 3 than 2. TV viewing became positively associated with BMI during the third study year.

CONCLUSION

Physical activity and TV viewing were the only significant predictors (other than baseline BMI) of BMI among a triethnic cohort of 3-4-y-old children followed for 3 y with both physical activity (negatively associated) and TV viewing (positively associated) becoming stronger predictors as the children aged. It appears that 6 or 7 y is a critical age when TV viewing and physical activity may affect BMI. Therefore, focusing on reducing time spent watching television and increasing time spent in physical activity may be successful means of preventing obesity among this age group.

A review of psychosocial pre-treatment predictors of weight control

Prompted by the large heterogeneity of individual results in obesity treatment, many studies have attempted to predict weight outcomes from information collected from participants before they start the programme. Identifying significant predictors of weight loss outcomes is central to improving treatments for obesity, as it could help professionals focus efforts on those most likely to benefit, suggest supplementary or alternative treatments for those less likely to succeed, and help in matching individuals to different treatments. To date, however, research efforts have resulted in weak predictive models with limited practical usefulness. The two primary goals of this article are to review the best individual-level psychosocial pre-treatment predictors of short- and long-term (1 year or more) weight loss and to identify research needs and propose directions for further work in this area. Results from original studies published since 1995 show that few previous weight loss attempts and an autonomous, self-motivated cognitive style are the best prospective predictors of successful weight management. In the more obese samples, higher initial body mass index (BMI) may also be correlated with larger absolute weight losses. Several variables, including binge eating, eating disinhibition and restraint, and depression/mood clearly do not predict treatment outcomes, when assessed before treatment. Importantly, for a considerable number of psychosocial constructs (e.g. eating self-efficacy, body image, self-esteem, outcome expectancies, weight-specific quality of life and several variables related to exercise), evidence is suggestive but inconsistent or too scant for an informed conclusion to be drawn. Results are discussed in the context of past and present conceptual and methodological limitations, and several future research directions are described.

Ratings of perceived exertion are not influenced by exercise stage of change in physically active college students

Comparisons of ratings of perceived exertion based on fitness have been equivocal but have not accounted for recent exercise history. The purpose of this study was to test mean differences in ratings of perceived exertion among individuals of differing exercise histories as measured by exercise stage of change. Participants completed questionnaires to measure exercise stage of change and physical activity [preparation stage (n=32), action stage (n=31), and maintenance stage (n=41)]. Ratings of perceived exertion were measured during a graded maximal exercise test. Individual regression equations were computed to estimate the ratings for 50%, 60%, 70%, and 80% of VO2 max. There were no significant differences in the ratings across the preparation, action, and maintenance stages. Therefore, the hypothesis that recent exercise history would influence ratings of perceived exertion during an aerobic fitness test was rejected.

America's obesity epidemic: measuring physical activity to promote an active lifestyle

The incidence of overweight and obesity in the United States and worldwide has reached epidemic proportions. To effectively intervene, dietetics professionals and other health care practitioners need to address both sides of the energy balance equation when counseling clients and patients. Often, the focus on energy intake supersedes the promotion of a physically active lifestyle. Incorporating appropriate and sufficient physical activity into one's life is an essential component of achieving and maintaining a healthful body weight. This review summarizes background knowledge on the benefits of physical activity for health and provides an overview of available tools for measuring physical activity and energy expenditure. The physical and mental health benefits of an active lifestyle, current physical activity recommendations for the US public, the prevalence of inactivity in the United States, and components of energy expenditure are reviewed. Additionally, tools for estimating total energy expenditure, resting metabolic rate, and physical activity are evaluated and suitable approaches for applying these tools are provided.