Distance learning strategies for weight management utilizing online social networks versus group phone conference call

OBJECTIVE

The increase in technology and online social networks (OSNs) may present healthcare providers with an innovative modality for delivering weight management programmes that could have an impact on health care at the population level. The objective of this study was to evaluate the feasibility and efficacy of using an OSN to deliver a weight loss programme to inform future, large-scale trials.

METHODS

Seventy individuals (age = 47 ± 12.4, minority = 24.3%) with obesity (BMI = 36.2 ± 4.0) completed a 6-month weight loss intervention and were randomized to either a conference call or OSN delivery group. Weight loss was achieved by reducing energy intake by 500-700 kcal·d-1 below estimated total daily energy expenditure and progressing physical activity to 300 min/week. Behavioural weight loss strategies were delivered weekly throughout the intervention.

RESULTS

Conference call and OSN groups produced clinically meaningful weight loss of ≥5% from baseline to 6 months (phone = -6.3 ± 6.4%, OSN = -5.8 ± 6.7%). There was no significant difference in weight change between groups (p = 0.765).

CONCLUSION

The phone and OSN groups met the American Heart Association/American College of Cardiology/The Obesity Society's Guidelines by reducing baseline weight by 5-10% within 6 months. OSNs appear to be a viable delivery platform for weight loss interventions; however, larger scale adequately powered trials are needed.

Physical activity and academic achievement across the curriculum: Results from a 3-year cluster-randomized trial

We compared changes in academic achievement across 3years between children in elementary schools receiving the Academic Achievement and Physical Activity Across the Curriculum intervention (A+PAAC), in which classroom teachers were trained to deliver academic lessons using moderate-to-vigorous physical activity (MVPA) compared to a non-intervention control. Elementary schools in eastern Kansas (n=17) were cluster randomized to A+PAAC (N=9, target ≥100min/week) or control (N=8). Academic achievement (math, reading, spelling) was assessed using the Wechsler Individual Achievement Test-Third Edition (WIAT-III) in a sample of children (A+PAAC=316, Control=268) in grades 2 and 3 at baseline (Fall 2011) and repeated each spring across 3years. On average 55min/week of A+PACC lessons were delivered each week across the intervention. Baseline WIAT-III scores (math, reading, spelling) were significantly higher in students in A+PAAC compared with control schools and improved in both groups across 3years. However, linear mixed modeling, accounting for baseline between group differences in WIAT-III scores, ethnicity, family income, and cardiovascular fitness, found no significant impact of A+PAAC on any of the academic achievement outcomes as determined by non-significant group by time interactions. A+PAAC neither diminished or improved academic achievement across 3-years in elementary school children compared with controls. Our target of 100min/week of active lessons was not achieved; however, students attending A+PAAC schools received an additional 55min/week of MVPA which may be associated with both physical and mental health benefits, without a reduction in time devoted to academic instruction.

Caregivers' effect on weight management in adults with intellectual and developmental disabilities

INTRODUCTION

Caregivers of adults with IDD often play a large role in the ability of adults with IDD to lose weight.

OBJECTIVE

The purpose of this study was to determine to examine the effects of the caregivers' perceived burdens and self-efficacy and their relationship to an individual (family member or paid staff) on weight changes across a weight management intervention for adults with IDD.

METHODS

Overweight/obese adults with mild to moderate IDD, along with assigned caregivers who served as their study partner, were randomized to an 18-month weight management intervention. The living environment and caregiver relationship were assessed at baseline. Caregivers completed questionnaires regarding perceived hassles, uplifts, and self-efficacy in helping the participant follow a weight management intervention.

RESULTS

147 adults with IDD (∼57% women and ∼16% minorities) were included in data analysis. After 18 months, there were no differences in weight loss between participants who had a family member as their study partner and those who had a paid assistant as their study partner (-5.5 ± 5.2% vs. -5.6± 5.3% p = 0.16). However, paid assistants reported more hassles with following the diet intervention at 6 months (p < 0.05). Participants who had a paid assistant as their study partner were more likely to have multiple study partners during the study, which was correlated with smaller weight loss.

CONCLUSION

While caregivers are important for weight management of adults with IDD, the caregiver's relationship to the participant does not affect weight change in an intervention.

Do weight management interventions delivered by online social networks effectively improve body weight, body composition, and chronic disease risk factors? A systematic review

Introduction Currently, no systematic review/meta-analysis has examined studies that used online social networks (OSN) as a primary intervention platform. Therefore, the purpose of this review was to evaluate the effectiveness of weight management interventions delivered through OSN. Methods PubMed, EMBASE, PsycINFO, Web of Science, and Scopus were searched (January 1990-November 2015) for studies with data on the effect of OSNs on weight loss. Only primary source articles that utilized OSN as the main platform for delivery of weight management/healthy lifestyle interventions, were published in English language peer-reviewed journals, and reported outcome data on weight were eligible for inclusion in this systematic review. Five articles were included in this review. Results One-hundred percent of the studies ( n = 5) reported a reduction in baseline weight. Three of the five studies (60%) reported significant decreases in body weight when OSN was paired with health educator support. Only one study reported a clinical significant weight loss of ≥5%. Conclusion Using OSN for weight management is in its early stages of development and, while these few studies show promise, more research is needed to acquire information about optimizing these interventions to increase their efficacy.

Weight management for adolescents with intellectual and developmental disabilities: Rationale and design for an 18month randomized trial

Adolescents with intellectual and developmental disabilities (IDD) are an underserved group in need of weight management. However, information regarding effective weight management for this group is limited, and is based primarily on results from small, non-powered, non-randomized trials that were not conducted in accordance with current weight management guidelines. Additionally, the comparative effectiveness of emerging dietary approaches, such as portion-controlled meals (PCMs) or program delivery strategies such as video chat using tablet computers have not been evaluated. Therefore, we will conduct an 18month trial to compare weight loss (6months) and maintenance (7-18months) in 123 overweight/obese adolescents with mild to moderate IDD, and a parent, randomized to a weight management intervention delivered remotely using FaceTime™ on an iPad using either a conventional meal plan diet (RD/CD) or a Stop Light diet enhanced with PCMs (RD/eSLD), or conventional diet delivered during face-to-face home visits (FTF/CD). This design will provide an adequately powered comparison of both diet (CD vs. eSLD) and delivery strategy (FTF vs. RD). Exploratory analyses will examine the influence of behavioral session attendance, compliance with recommendations for diet (energy intake), physical activity (min/day), self-monitoring of diet and physical activity, medications, and parental variables including diet quality, physical activity, baseline weight, weight change, and beliefs and attitudes regarding diet and physical activity on both weight loss and maintenance. We will also complete a cost and contingent valuation analysis to compare costs between RD and FTF delivery.

Voxel-based morphometry reveals brain gray matter volume changes in successful dieters

OBJECTIVE

To compare regional brain volume predictors of percent weight loss (WL) in dieters with obesity (DwO) and in the same participants categorized as "successful" (≥7% WL) or "unsuccessful" dieters (<7% WL).

METHODS

DwO (n = 72) and participants with healthy weight (n = 22) completed a structural MRI at baseline and 3 months. All DwO participants were enrolled in a 12-week program consisting of a reduced calorie diet, increased physical activity, and behavioral modification. SPM8-based voxel-based morphometry processing streams were used for measurements of regional gray (GMV) and white matter volume and longitudinal changes in volume. Correlations between WL and baseline brain volume and change in brain volume, as well as differences between groups, were then tested.

RESULTS

%WL was positively correlated with baseline GMV in right parahippocampal and orbitofrontal gyri in DwO. Successful dieters showed greater GMV loss in the left precentral gyrus and the insula compared with unsuccessful dieters. A negative correlation was found between %WL and GMV change from baseline in the left prefrontal regions.

CONCLUSIONS

Findings illustrate that WL is related to volumetric changes in brain areas previously linked to interoception and food motivation.

Energy and Macronutrient Intake in the Midwest Exercise Trial 2 (MET-2)

PURPOSE

This study aimed to examine the effect of exercise training over 10 months at two levels of energy expenditure on energy and macronutrient intake in a sample of previously sedentary, overweight/obese young adults.

METHODS

We conducted a 10-month trial in 141 young adults who were randomized to either supervised exercise 5 d·wk(-1) at 400 and 600 kcal per session or nonexercise control. Participants were instructed to maintain their usual ad libitum diet. Energy/macronutrient intake was assessed at baseline and 3.5, 7, and 10 months over 7-d periods of ad libitum eating in a university cafeteria using digital photography. Foods consumed outside the cafeteria were assessed using multiple-pass recalls.

RESULTS

There were no significant between-group differences in absolute energy intake at baseline or at any other time point in the total sample or in men. In women, absolute energy intake was significantly greater in the 600-kcal-per-session group versus controls at both 3.5 and 7 months. There were no significant between-group differences in relative energy intake (kcal·kg·d(-1)) at any time point in the total sample, in men or women. There were no significant within- or between-group differences of change in absolute or relative energy intake in any of the three study groups in the total sample or in men or women. No clinically relevant changes in macronutrient intake were observed.

CONCLUSIONS

Aerobic exercise training does not significantly alter energy or macronutrient intake in overweight and obese young adults. The possibility of a threshold level beyond which increased exercise energy expenditure fails to produce a more negative energy balance and potential sex differences in the energy intake response to increased levels of exercise are potentially important.

Tracking the relationship between children's aerobic fitness and cognitive control

OBJECTIVE

To investigate if changes in aerobic fitness over a 3-year period are associated with modulations in children's cognitive control.

METHOD

A sample of 2nd/3rd-grade children (N = 290) completed baseline measures in Fall of 2011, and again in Spring of 2014 at the end of 4th/5th grade. Children completed the Progressive Aerobic Cardiovascular Endurance Run (PACER) test to measure aerobic capacity, a flanker task to evaluate inhibitory control, and an n-back task to assess working memory. Aerobic fitness was included as an independent variable in hierarchical regression analyses conducted at both time points, in addition to analyses examining changes in cognition over time.

RESULTS

At baseline, higher fit children exhibited shorter overall flanker reaction time (RT), as well as superior accuracy and d' scores (i.e., target discrimination) for both 1- and 2-back conditions. Approximately 3 years later, higher levels of fitness were associated with better performance for only the most difficult conditions of each task, including greater incongruent flanker accuracy and less interference during the compatible condition, as well as better accuracy and target discrimination for the 2-back condition of the n-back task. Importantly, increases in fitness were independently related to improvements in incongruent flanker accuracy and 2-back d' scores.

CONCLUSIONS

The current findings indicate that both higher aerobic fitness levels as well as increases in children's fitness are associated with better performance for task conditions eliciting greater cognitive demand. Such evidence is vital for implementing future health recommendations intended to foster improved cognitive performance in children. (PsycINFO Database Record

Exercise volume and aerobic fitness in young adults: the Midwest Exercise Trial-2

To examine the effect of exercise volume at a fixed intensity on changes in aerobic fitness. Ninety-two overweight/obese individuals (BMI 25-40 kg m(2)), age 18-30 years, 50 % women, completed a 10 mo, 5 d wk(-1) supervised exercise intervention at 2 levels of exercise energy expenditure (400 or 600 kcal session(-1)) at 70-80 % heart rate (HR) max. Exercise consisted primarily of walking/jogging on motor-driven treadmills. The duration and intensity of all exercise sessions were verified by a downloadable HR monitor set to collect HR in 1-min epochs. All participants were instructed to continue their typical patterns of non-exercise physical activity and dietary intake over the duration of the 10 mo intervention. Maximal aerobic capacity (indirect calorimetry) was assessed on a motor-driven treadmill using a modified Balke protocol at baseline, mid-point (5 mo), and following completion of the 10 mo intervention. VO2 max (L min(-1)) increased significantly in both the 400 (11.3 %) and 600 kcal session(-1) groups (14 %) compared to control (-2.0 %; p < 0.001); however, the differences between exercise groups were not significant. Similar results were noted for change in relative VO2 max (mL kg(-1) min(-1)); however, the magnitude of change was greater than for absolute VO2 max (L min(-1)) (400 group = 18.3 %; 600 group = 20.2 %) due to loss of body weight over the 10-mo intervention in both exercise groups. Our results indicate that exercise volume was not associated with change in aerobic fitness in a sample of previously sedentary, overweight and obese young adults.

Longitudinal Weight Loss Patterns and their Behavioral and Demographic Associations

BACKGROUND

Identification of weight change patterns may allow tailored interventions to improve long-term weight loss.

PURPOSE

To identify patterns of weight change over 18 months, and assess participant characteristics and intervention adherence factors associated with weight change patterns in a sample of 359 overweight/obese adults.

METHODS

Weight loss (0-6 months) was achieved with reduced energy intake and increased physical activity (PA). Maintenance (7-18 months) provided adequate energy to maintain weight and continued PA.

RESULTS

Latent profile analysis identified three weight change profiles. During weight loss/maintenance, participants in profiles 2 and 3 (18-month weight loss ∼14 %) attended more behavioral sessions and performed more PA compared with profile 1 (18-month weight loss <1 %). Self-efficacy for both weight management and exercise barriers were higher in profiles 2 and 3 compared with profile 1 following weight loss and during maintenance.

CONCLUSION

Weight change patterns can be identified and are associated with both participant characteristics and intervention adherence.

Breakfast Intake and Composition Is Associated with Superior Academic Achievement in Elementary Schoolchildren

OBJECTIVE

To determine whether breakfast consumption or content affects academic achievement measured by standardized tests.

METHODS

Baseline data were collected in fall of 2011 from 698 students (50.5% female, age = 7.5 ± 0.6 years) living in the state of Kansas. Academic achievement was assessed using 3 components from the Wechsler Individual Achievement Test (WIAT-III). Prior to taking the WIAT-III, participants completed a breakfast recall of all foods and drinks consumed that morning, which was analyzed using Nutrition Data System for Research (NDS-R). WIAT-III scores were compared between breakfast and non-breakfast consumers in a sample (n = 162) matched for age, sex, race, education level of both parents, household income, body mass index (BMI), and cardiovascular fitness, and Pearson correlations were calculated from all breakfast eaters (n = 617) between test performance and components of the breakfast.

RESULTS

When compared to non-breakfast consumers, the breakfast consumers had significantly higher scores in all 3 WIAT-III components (all p < 0.05). In breakfast consumers, servings of fruit juice were negatively correlated with reading comprehension and fluency standard score and mathematics standard score (both p < 0.0001), and greater servings of whole grains were significantly related to higher scores in reading comprehension and fluency and mathematics (both p < 0.05).

CONCLUSION

Both breakfast consumption and the content may be associated with improved standardized test performance in elementary school students.

A virtual reality intervention (Second Life) to improve weight maintenance: Rationale and design for an 18-month randomized trial

Despite the plethora of weight loss programs available in the US, the prevalence of overweight and obesity (BMI≥25kg/m(2)) among US adults continues to rise at least, in part, due to the high probability of weight regain following weight loss. Thus, the development and evaluation of novel interventions designed to improve weight maintenance are clearly needed. Virtual reality environments offer a promising platform for delivering weight maintenance interventions as they provide rapid feedback, learner experimentation, real-time personalized task selection and exploration. Utilizing virtual reality during weight maintenance allows individuals to engage in repeated experiential learning, practice skills, and participate in real-life scenarios without real-life repercussions, which may diminish weight regain. We will conduct an 18-month effectiveness trial (6 months weight loss, 12 months weight maintenance) in 202 overweight/obese adults (BMI 25-44.9kg/m(2)). Participants who achieve ≥5% weight loss following a 6month weight loss intervention delivered by phone conference call will be randomized to weight maintenance interventions delivered by conference call or conducted in a virtual environment (Second Life®). The primary aim of the study is to compare weight change during maintenance between the phone conference call and virtual groups. Secondarily, potential mediators of weight change including energy and macronutrient intake, physical activity, consumption of fruits and vegetables, self-efficacy for both physical activity and diet, and attendance and completion of experiential learning assignments will also be assessed.

Nonexercise energy expenditure and physical activity in the Midwest Exercise Trial 2

PURPOSE

This study aimed to examine compensatory changes in nonexercise energy expenditure (NEEx) and nonexercise physical activity (NEPA) in response to an aerobic exercise training program.

METHODS

Ninety-two overweight/obese (body mass index, 25-39.9 kg·m) sedentary young adults (18-30 yr) completed a 10-month randomized clinical efficacy trial of aerobic exercise 5 d·wk at either 400 kcal per session (n = 37), 600 kcal per session (n = 37), or control (n = 18). Total daily energy expenditure (TDEE) and resting metabolic rate (RMR) were measured at months 0 and 10. NEPA was measured by an accelerometer at months 0, 3.5, 7, and 10. NEEx was calculated by the following formula: [(total daily energy expenditure × 0.9) - RMR] - net EEEx (EEEx-RMR). Mixed modeling was used to examine differences between groups (group effect), within groups (time effect), and group-time interaction for NEEx and NEPA.

RESULTS

Within the exercise groups, there were no significant effects (all P > 0.05) of group, time, or group-time interaction for NEPA. In addition, there were no significant within- or between-group differences for change in NEEx. However, activity counts per minute were significantly higher (P < 0.001) in the 600-kcal-per-session group (346 ± 141 min·d) versus controls (290 ± 106 min·d) at month 7 and significantly higher (P < 0.001) in both the 600-kcal-per-session (345 ± 163 min·d) and 400-kcal-per-session groups (317 ± 146 min·d) versus controls (277 ± 116 min·d) at 10 months.

CONCLUSIONS

A 10-month aerobic exercise training program in previously sedentary, overweight and obese young adults was not associated with compensatory decreases in NEEx or NEPA. Results suggest that overweight and obese individuals do not become less physically active or spend more time in sedentary pursuits in response to exercise.

Energy intake, nonexercise physical activity, and weight loss in responders and nonresponders: The Midwest Exercise Trial 2

OBJECTIVE

To compare energy intake, total daily energy expenditure (TDEE), nonexercise energy expenditure (NEEx), resting metabolic rate (RMR), nonexercise physical activity (NEPA), and sedentary time between participants with weight loss <5% (nonresponders) vs. ≥5% (responders) in response to exercise.

METHODS

Adults (18-30 years) with overweight/obesity (BMI 25-40 kg/m(2) ) were randomized to exercise: 5 days/week, 400 or 600 kcal/session, 10 months.

RESULTS

Of the participants, 40 responded and 34 did not respond to the exercise protocol. Nonresponder energy intake was higher vs. responders, significant only in men (P=0.034). TDEE increased only in responders (P=0.001). NEEx increased in responders and decreased in nonresponders, significant only in men (P=0.045). There were no within- or between-group differences for change in RMR. NEPA increased in responders and decreased in nonresponders (group-by-time interactions: total sample, P=0.049; men, P=0.016). Sedentary time decreased in both groups, significant only in men.

CONCLUSIONS

Men who did not lose weight in response to exercise (<5%) had higher energy intake and lower NEEx when compared with men losing ≥5%. No significant differences in any parameters assessed were observed between women who lost <5% vs. those losing ≥5%. Factors associated with the weight loss response to exercise in women warrant additional investigation.

Parents' perspective on weight management interventions for adolescents with intellectual and developmental disabilities

BACKGROUND

Adolescents with intellectual and developmental disabilities (IDD) have high rates of obesity. However, little research has been conducted demonstrating effective strategies and barriers for weight loss or weight management in adolescents with IDD. Furthermore, parents play a large role in terms of weight management in children and adolescents with IDD, and their views should be taken into consideration when designing a diet and PA intervention for weight management.

OBJECTIVE

The aims of this study are to better understand the parents' perspectives on the strategies and barriers for helping children and adolescents with IDD be successful in a weight management program and to identify how this information to guide future approaches.

METHODS

Semi-structured interviews were conducted in 18 parents whose children had just finished a diet and PA intervention. Interviews were transcribed verbatim, and thematic analysis was performed.

RESULTS

Parents reported a positive attitude toward the program, liked the convenience of the program, and felt that they learned beneficial strategies to encourage healthy habits in the home. Parents found time to be a major barrier to supporting their child with a diet and PA intervention. Parents were willing to change their own dietary behaviors to help their children successfully follow a weight loss intervention; however, no parent reported changing their own PA levels.

CONCLUSION

Future diet and PA studies should aim to reduce parental time commitment and increase importance of PA.

Predicting resting energy expenditure in young adults

PURPOSE

To develop and validate a REE prediction equation for young adults.

METHODS

Baseline data from two studies were pooled (N=318; women=52%) and randomly divided into development (n=159) and validation samples (n=159). REE was measured by indirect calorimetry. Stepwise regression was used to develop an equation to predict REE (University of Kansas (KU) equation). The KU equation and 5 additional REE prediction equations used in clinical practice (Mifflin-St. Jeor, Harris-Benedict, Owens, Frankenfield (2 equations)) were evaluated in the validation sample.

RESULTS

There were no significant differences between predicted and measured REE using the KU equation for either men or women. The Mifflin-St. Jeor equation showed a non-significant mean bias in men; however, mean bias was statistically significant in women. The Harris-Benedict equation significantly over-predicted REE in both men and women. The Owens equation showed a significant mean bias in both men and women. Frankenfield equations #1 and #2 both significantly over-predicted REE in non-obese men and women. We found no significant differences between measured REE and REE predicted by the Frankenfield #2 equations in obese men and women.

CONCLUSION

The KU equation, which uses easily assessed characteristics (age, sex, weight) may offer better estimates of REE in young adults compared with the 5 other equations. The KU equation demonstrated adequate prediction accuracy, with approximately equal rates of over and under-prediction. However, enthusiasm for recommending any REE prediction equations evaluated for use in clinical weight management is damped by the highly variable individual prediction error evident with all these equations.

Dose-Response of Aerobic Exercise on Cognition: A Community-Based, Pilot Randomized Controlled Trial

Epidemiological studies suggest a dose-response relationship exists between physical activity and cognitive outcomes. However, no direct data from randomized trials exists to support these indirect observations. The purpose of this study was to explore the possible relationship of aerobic exercise dose on cognition. Underactive or sedentary participants without cognitive impairment were randomized to one of four groups: no-change control, 75, 150, and 225 minutes per week of moderate-intensity semi-supervised aerobic exercise for 26-weeks in a community setting. Cognitive outcomes were latent residual scores derived from a battery of 16 cognitive tests: Verbal Memory, Visuospatial Processing, Simple Attention, Set Maintenance and Shifting, and Reasoning. Other outcome measures were cardiorespiratory fitness (peak oxygen consumption) and measures of function functional health. In intent-to-treat (ITT) analyses (n = 101), cardiorespiratory fitness increased and perceived disability decreased in a dose-dependent manner across the 4 groups. No other exercise-related effects were observed in ITT analyses. Analyses restricted to individuals who exercised per-protocol (n = 77) demonstrated that Simple Attention improved equivalently across all exercise groups compared to controls and a dose-response relationship was present for Visuospatial Processing. A clear dose-response relationship exists between exercise and cardiorespiratory fitness. Cognitive benefits were apparent at low doses with possible increased benefits in visuospatial function at higher doses but only in those who adhered to the exercise protocol. An individual’s cardiorespiratory fitness response was a better predictor of cognitive gains than exercise dose (i.e., duration) and thus maximizing an individual’s cardiorespiratory fitness may be an important therapeutic target for achieving cognitive benefits.

Resting-state brain connectivity after surgical and behavioral weight loss

OBJECTIVE

Changes in food-cue neural reactivity associated with behavioral and surgical weight loss interventions have been reported. Resting functional connectivity represents tonic neural activity that may contribute to weight loss success. This study explores whether intervention type is associated with differences in functional connectivity after weight loss.

METHODS

Fifteen participants with obesity were recruited prior to adjustable gastric banding surgery. Thirteen demographically matched participants with obesity were selected from a separate behavioral diet intervention. Resting-state functional magnetic resonance imaging was collected 3 months after surgery/behavioral intervention. ANOVA was used to examine post-weight loss differences between the two groups in connectivity to seed regions previously identified as showing differential cue-reactivity after weight loss.

RESULTS

Following weight loss, behavioral dieters exhibited increased connectivity between left precuneus/superior parietal lobule (SPL) and bilateral insula pre- to postmeal and bariatric patients exhibited decreased connectivity between these regions pre- to postmeal (P(corrected) <0.05).

CONCLUSIONS

Behavioral dieters showed increased connectivity pre- to postmeal between a region associated with processing of self-referent information (precuneus/SPL) and a region associated with interoception (insula) whereas bariatric patients showed decreased connectivity between these regions. This may reflect increased attention to hunger signals following surgical procedures and increased attention to satiety signals following behavioral diet interventions.

Dose-response relationship of cardiorespiratory fitness adaptation to controlled endurance training in sedentary older adults

BACKGROUND

The purpose of this investigation was to identify a quantitative dose-response relationship for enhancing maximal oxygen consumption (VO2max) in healthy sedentary older adults after controlled endurance training.

METHODS AND RESULTS

This meta-analysis of controlled clinical trials included 1257 exercisers and 845 controls with a mean age of 67.45 ± 5.25 years. Effect sizes were calculated for training-induced VO2max changes. Different training regimens were analyzed and compared. The weighted net change of the mean VO2max values showed a significant increase of 3.78 ml/kg per min (95% confidence interval = 3.29 to 4.27; p < 0.0001) in response to aerobic training. Interstudy differences in VO2max changes were significantly related to exercise intensity, and explained approximately 11% of the variance of the VO2max responses. VO2max improved significantly at 35%-50% heart rate reserve (HRR) and continued improving at a greater rate with increasing "dose". The largest VO2max-improvement adaptation was achieved with a mean intensity of 66%-73% HRR. The magnitudes of the VO2max adaptation are identical to exercise at 57%-65% HRR and at 75%-80% HRR. Higher intensity doses more than 75-80% HRR did not lead to greater enhancement of VO2max improvements but, conversely, resulted in large declines.

CONCLUSIONS

Our data provide quantitative insight into the magnitude of VO2max alterations as affected by exercise intensity, duration, frequency, and program length. The shapes of the dose-response curves are not simply linear, but with many similar trends and noteworthy characteristics. Aerobic training at a mean intensity of 66%-73% HRR with 40-50 min per session for 3-4 day/week for 30-40 weeks appears to be effective and optimal for maximum cardiorespiratory benefits in healthy sedentary older adults.

Length of moderate-to-vigorous physical activity bouts and cardio-metabolic risk factors in elementary school children

BACKGROUND

Accumulating moderate-to-vigorous physical activity (MVPA) in bouts of 10 min is associated with improved cardio-metabolic risk factors (CMRF) in adults.

PURPOSE

To assess the association between the lengths of MVPA bouts and CMRF in elementary school age children.

METHODS

The sample included 396, 2nd and 3rd grade students from eastern Kansas (182 boys, 214 girls; age 7.6 ± 0.6 years; Body Mass Index Percentile [BMI%ile]: 61.6 ± 9.3) in the fall of 2011. Analyses were conducted in 2014. MVPA bouts were defined as sporadic (<5 min), short (5-<10 min) or medium-to-long (≥10 min). Latent profile analysis was used to identify distinct subgroups (classes) based on the composition of MVPA bouts. Bayesian probability-based Wald chi-square test was used to compare CMRF between classes controlling for age, sex, BMI%ile, and total moderate and total vigorous PA.

RESULTS

Three classes of accumulated physical activity were identified: A (n=78); 97% sporadic 2%, short, 1% medium-to-long bouts; B (n=174); 93% sporadic, 5% short, 2% medium-to-long; C (n=144); and 86% sporadic, 9% short, 5% medium-to-long bouts. Class C had significantly lower BMI%ile (57.3 ± 2.3 (SE)), waist circumference (WC; 55.8 ± 0.5 cm) compared with Class A (BMI%ile=70.9±0.5, p<0.01.030, WC=61.0 ± 1.0 cm, p=0.<0.01). Class B had significantly lower WC (56.6 ± 0.6 cm), p<0.01 than Class A. No significant differences between classes were shown in other outcomes.

CONCLUSION

Children who accumulated MVPA with a higher percentage of short (5-<10 min) and medium-to-long bouts (≥10min) had lower BMI%ile, and WC compared with children who accumulated MVPA with a lower percentage short and medium-to-long bouts.

Cognitive control in preadolescent children with risk factors for metabolic syndrome

OBJECTIVE

To investigate the relationship between cognitive control and metabolic syndrome (MetS) risk factors in preadolescent children while controlling for aerobic fitness and weight status.

METHODS

Hierarchical regression analyses were conducted using aerobic fitness, demographic, and MetS risk-factor variables in a sample of 2nd- and 3rd-grade children (n = 139) who performed a modified version of a flanker task to assess cognitive control. Flanker performance was also compared between children that met no MetS risk-factor criteria (n = 70), and children who met 1 criterion or more (n = 69).

RESULTS

Regression analyses indicated that after controlling for demographic variables and fitness, HDL cholesterol exhibited an independent negative association with flanker reaction time (RT). Group comparisons further revealed that children with no risk factors demonstrated overall shorter RT than the at-risk group. In addition, at-risk children exhibited larger accuracy-interference scores (i.e., poorer performance) for the more difficult conditions of the flanker task that required the up-regulation of cognitive control to meet elevated task demands.

CONCLUSIONS

These findings are consonant with the previous literature reporting a beneficial influence of aerobic fitness on cognitive control, and reveal new evidence that children without risk factors for MetS exhibit better inhibitory control and increased cognitive flexibility than do at-risk children. In addition to aerobic fitness, these risk factors may serve as important biomarkers for understanding the potential cognitive implications of MetS risk in younger generations.

Portion-controlled meals provide increases in diet quality during weight loss and maintenance

BACKGROUND

Behavioural weight-loss interventions utilising portion-controlled meals (PCMs) produce significant decreases in weight. However, their impact on diet quality during weight maintenance is unknown. The present study aimed to assess the influence of a weight management intervention employing PCMs and increased physical activity on diet quality during weight loss and weight maintenance.

METHODS

One hundred and ninety-seven overweight and obese adults [67% women; mean (SD) BMI = 34.0 (4.6) kg m(-2); age = 46.1 (8.9) years] completed an 18-month trial. The weight-loss phase (0-6 months) consisted of energy restriction, which was achieved using PCMs plus fruits and vegetables and increased physical activity. During weight maintenance (6-18 months), participants consumed a diet designed to maintain weight loss. Body weight and dietary intake were assessed at baseline, and at 6, 12 and 18 months. The Healthy Eating Index-2010 (HEI) was calculated using data obtained from 3-day food records.

RESULTS

Mean (SD) body weight was 14.3% (6.6%) and 8.7% (8.0%) below baseline at 6 and 18 months, respectively. The mean (SD) HEI-2010 score after weight loss [66.6 (9.4)] was significantly higher than baseline [46.4 (8.9)] and remained significantly higher than baseline at 18 months [57.7 (10.6)] (both P < 0.001).

CONCLUSIONS

A weight management intervention using PCMs resulted in both clinically significant weight loss and increased diet quality scores, demonstrating that the use of PCMs during weight loss allows for meaningful changes in diet quality during weight maintenance.

Brain function predictors and outcome of weight loss and weight loss maintenance

Obesity rates are associated with public health consequences and rising health care costs. Weight loss interventions, while effective, do not work for everyone, and weight regain is a significant problem. Eating behavior is influenced by a convergence of processes in the brain, including homeostatic factors and motivational processing that are important contributors to overeating. Initial neuroimaging studies have identified brain regions that respond differently to visual food cues in obese and healthy weight individuals that are positively correlated with reports of hunger in obese participants. While these findings provide mechanisms of overeating, many important questions remain. It is not known whether brain activation patterns change after weight loss, or if they change differentially based on amount of weight lost. Also, little is understood regarding biological processes that contribute to long-term weight maintenance. This study will use neuroimaging in participants while viewing food and non-food images. Functional Magnetic Resonance Imaging will take place before and after completion of a twelve-week weight loss intervention. Obese participants will be followed though a 6-month maintenance period. The study will address three aims: 1. Characterize brain activation underlying food motivation and impulsive behaviors in obese individuals. 2. Identify brain activation changes and predictors of weight loss. 3. Identify brain activation predictors of weight loss maintenance. Findings from this study will have implications for understanding mechanisms of obesity, weight loss, and weight maintenance. Results will be significant to public health and could lead to a better understanding of how differences in brain activation relate to obesity.

Linear/nonlinear relations of activity and fitness with children's academic achievement

A growing research base suggests that the benefits of physical activity (PA) and aerobic fitness for children extend beyond overall health/well-being to include academic achievement (AA). The majority of research studies on relations of PA and fitness with AA have used linear-only analytic approaches, thereby precluding the possibility that PA and fitness could have a differing effect on AA for those more/less active or fit.

OBJECTIVE

This study aimed to evaluate both linear and nonlinear associations of PA and aerobic fitness with children's AA among a sample of 687 second and third grade students from 17 Midwest schools.

STUDY DESIGN

Using baseline data (fall 2011) from a larger 3-yr intervention trial, multilevel regression analyses examined the linear and nonlinear associations of AA with PA and with progressive aerobic cardiovascular endurance run (PACER) laps (i.e., aerobic fitness), controlling for relevant covariates.

RESULTS

Fitness, but not PA, had a significant quadratic association with both spelling and mathematics achievement. Results indicate that 22-28 laps on the PACER was the point at which the associated increase in achievement per lap plateaued for spelling and mathematics.

CONCLUSIONS

Increasing fitness could potentially have the greatest effect on children's AA for those below the 50th fitness percentile on the PACER.

Aerobic capacity and cognitive control in elementary school-age children

PURPOSE

The current study examined the relationship between children's performance on the Progressive Aerobic Cardiovascular Endurance Run subtest of the FitnessGram® and aspects of cognitive control that are believed to support academic success.

METHODS

Hierarchical linear regression analyses were conducted on a sample of second- and third-grade children (n = 397) who completed modified versions of a flanker task and spatial n-back task to assess inhibitory control and working memory, respectively.

RESULTS

Greater aerobic fitness was significantly related to shorter reaction time and superior accuracy during the flanker task, suggesting better inhibitory control and the facilitation of attention in higher-fit children. A similar result was observed for the n-back task such that higher-fit children exhibited more accurate target detection and discrimination performance when working memory demands were increased.

CONCLUSIONS

These findings support the positive association between aerobic fitness and multiple aspects of cognitive control in a large sample of children, using a widely implemented and reliable field estimate of aerobic capacity. Importantly, the current results suggest that this relationship is consistent across methods used to assess fitness, which may have important implications for extending this research to more representative samples of children in a variety of experimental contexts.

The use of technology for delivering a weight loss program for adolescents with intellectual and developmental disabilities

Adolescents with intellectual and developmental disabilities (IDD) are at an increased risk of obesity, with up to 55% considered overweight and 31% obese. However, there has been minimal research on weight management strategies for adolescents with IDD. The purpose of this study was to compare the effectiveness of two weight loss diets, an enhanced Stop Light Diet (eSLD) and a conventional diet (CD), and to determine the feasibility of using tablet computers as a weight loss tool in overweight and obese adolescents with IDD. A 2-month pilot intervention was conducted. All participants were randomized to the eSLD or CD and were given a tablet computer that they used to track daily dietary intake and physical activity. Participants and parents met weekly with a registered dietitian nutritionist via video chat on the tablet computer to receive diet and physical activity feedback and education. Twenty participants (45% female, aged 14.9±2.2 years) were randomized and completed the intervention. Participants in both diets were able to lose weight, and there were no significant differences between the eSLD and CD (-3.89±2.66 kg vs -2.22±1.37 kg). Participants were able to use the tablet computer to track their dietary intake 83.4%±21.3% of possible days and to attend 80.0% of the video chat meetings. Both dietary interventions appear to promote weight loss in adolescents with IDD, and the use of tablet computers appears to be a feasible tool to deliver a weight loss intervention in adolescents with IDD.

Resistance to exercise-induced weight loss: compensatory behavioral adaptations

In many interventions that are based on an exercise program intended to induce weight loss, the mean weight loss observed is modest and sometimes far less than what the individual expected. The individual responses are also widely variable, with some individuals losing a substantial amount of weight, others maintaining weight, and a few actually gaining weight. The media have focused on the subpopulation that loses little weight, contributing to a public perception that exercise has limited utility to cause weight loss. The purpose of the symposium was to present recent, novel data that help explain how compensatory behaviors contribute to a wide discrepancy in exercise-induced weight loss. The presentations provide evidence that some individuals adopt compensatory behaviors, that is, increased energy intake and/or reduced activity, that offset the exercise energy expenditure and limit weight loss. The challenge for both scientists and clinicians is to develop effective tools to identify which individuals are susceptible to such behaviors and to develop strategies to minimize their effect.

A comparison of functional brain changes associated with surgical versus behavioral weight loss

OBJECTIVE

Few studies have examined brain changes in response to effective weight loss; none have compared different methods of weight-loss intervention. Functional brain changes associated with a behavioral weight loss intervention to those associated with bariatric surgery were compared.

DESIGN AND METHODS

Fifteen obese participants were recruited prior to adjustable gastric banding surgery and 16 obese participants were recruited prior to a behavioral diet intervention. Groups were matched for demographics and amount of weight lost. Functional magnetic resonance imaging scans (visual food motivation paradigm while hungry and following a meal) were conducted before and 12 weeks after surgery/behavioral intervention.

RESULTS

When compared to bariatric patients in the premeal analyses, behavioral dieters showed increased activation to food images in right medial prefrontal cortex (PFC) and left precuneus following weight loss. When compared to behavioral dieters, bariatric patients showed increased activation in bilateral temporal cortex following weight loss.

CONCLUSIONS

Behavioral dieters showed increased responses to food cues in medial PFC-a region associated with valuation and processing of self-referent information-when compared to bariatric patients. Bariatric patients showed increased responses to food cues in brain regions associated with higher level perception-when compared to behavioral dieters. The method of weight loss determines unique changes in brain function.

Does increased prescribed exercise alter non-exercise physical activity/energy expenditure in healthy adults? A systematic review

Prescribed physical activity/exercise training may reduce non-exercise physical activity resulting in no change in total daily energy expenditure and no or minimal exercise-induced weight loss. This systematic review evaluated cross-sectional, short-term (2-14 d), randomized and non-randomized trials which reported on the effect of prescribed physical activity/exercise on non-exercise physical activity/energy expenditure in healthy adults. PubMed and Embase were searched (from January 1990 to March 2013) for articles that presented data on the change in non-exercise physical activity/energy expenditure in response to prescribed physical activity/exercise training. Thirty-one articles were included in this review. One-hundred per cent of cross-sectional studies (n = 4), 90% of short-term studies (n = 10), 50% of non-randomized trials (n = 10) and 100% of randomized trials (n = 7) reported no reductions in non-exercise physical activity/energy expenditure in response to prescribed physical activity/exercise training. We found minimal evidence to support the hypothesis that prescribed physical activity/exercise training results in decreased non-exercise physical activity/energy expenditure in healthy adults. However, this literature is limited by the lack of adequately powered trials designed specifically to evaluate this hypothesis which have included assessments of both the energy expenditure of prescribed exercise and non-exercise energy expenditure using state-of-the-art techniques, i.e. indirect calorimetry and doubly labelled water, respectively.

Does increased exercise or physical activity alter ad-libitum daily energy intake or macronutrient composition in healthy adults? A systematic review

BACKGROUND

The magnitude of the negative energy balance induced by exercise may be reduced due to compensatory increases in energy intake.

OBJECTIVE

TO ADDRESS THE QUESTION: Does increased exercise or physical activity alter ad-libitum daily energy intake or macronutrient composition in healthy adults?

DATA SOURCES

PubMed and Embase were searched (January 1990-January 2013) for studies that presented data on energy and/or macronutrient intake by level of exercise, physical activity or change in response to exercise. Ninety-nine articles (103 studies) were included.

STUDY ELIGIBILITY CRITERIA

Primary source articles published in English in peer-reviewed journals. Articles that presented data on energy and/or macronutrient intake by level of exercise or physical activity or changes in energy or macronutrient intake in response to acute exercise or exercise training in healthy (non-athlete) adults (mean age 18-64 years).

STUDY APPRAISAL AND SYNTHESIS METHODS

Articles were grouped by study design: cross-sectional, acute/short term, non-randomized, and randomized trials. Considerable heterogeneity existed within study groups for several important study parameters, therefore a meta-analysis was considered inappropriate. Results were synthesized and presented by study design.

RESULTS

No effect of physical activity, exercise or exercise training on energy intake was shown in 59% of cross-sectional studies (n = 17), 69% of acute (n = 40), 50% of short-term (n = 10), 92% of non-randomized (n = 12) and 75% of randomized trials (n = 24). Ninety-four percent of acute, 57% of short-term, 100% of non-randomized and 74% of randomized trials found no effect of exercise on macronutrient intake. Forty-six percent of cross-sectional trials found lower fat intake with increased physical activity.

LIMITATIONS

The literature is limited by the lack of adequately powered trials of sufficient duration, which have prescribed and measured exercise energy expenditure, or employed adequate assessment methods for energy and macronutrient intake.

CONCLUSIONS

We found no consistent evidence that increased physical activity or exercise effects energy or macronutrient intake.

Evening hyperphagia and food motivation: a preliminary study of neural mechanisms

Evening hyperphagia (EH; consumption of ≥25% of total daily calories after the evening meal) is a circadian delay in the pattern of daily food intake and is a core criterion of night eating syndrome (Allison et al., 2010). This preliminary study examined the brain response to food cues using functional magnetic resonance imaging (fMRI) in seven obese adults with EH compared to seven obese adults without EH. When contrasting food to non-food and blurry baseline images pre-meal, groups differed in brain activation in the inferior frontal gyrus, precentral gyrus, cingulate gyrus, superior temporal gyrus and cerebellum. At post meal, groups differed in brain activation in the fusiform gyrus, inferior frontal gyrus, inferior parietal lobule and the cerebellum. Significant interactions between time (pre-meal, post-meal) and group (EH, control) when contrasting food to non-food images were also noted in the inferior frontal gyrus and the superior temporal gyrus. Further research is necessary to replicate these findings and determine if they have a mechanistic role in the development of circadian delayed eating behavior in obese adults with EH.

Neuroimaging studies of factors related to exercise: rationale and design of a 9 month trial

The prevalence of obesity is high resulting from chronic imbalances between energy intake and expenditure. On the expenditure side, regular exercise is associated with health benefits, including enhanced brain function. The benefits of exercise are not immediate and require persistence to be realized. Brain regions associated with health-related decisions, such as whether or not to exercise or controlling the impulse to engage in immediately rewarding activities (e.g., sedentary behavior), include reward processing and cognitive control regions. A 9 month aerobic exercise study will be conducted in 180 sedentary adults (n = 90 healthy weight [BMI = 18.5 to 26.0 kg/m(2)]; n = 90 obese [BMI = 29.0 to 41.0 kg/m(2)) to examine the brain processes underlying reward processing and impulse control that may affect adherence in a new exercise regimen. The primary aim is to use functional magnetic resonance imaging (fMRI) to examine reward processing and impulse control among participants that adhere (exercise >80% of sessions) and those that do not adhere to a nine-month exercise intervention with secondary analyses comparing sedentary obese and sedentary healthy weight participants. Our results will provide valuable information characterizing brain activation underlying reward processing and impulse control in sedentary obese and healthy weight individuals. In addition, our results may identify brain activation predictors of adherence and success in the exercise program along with measuring the effects of exercise and improved fitness on brain activation.

The Midwest Exercise Trial for the Prevention of Weight Regain: MET POWeR

Weight reduction in overweight and obese individuals results in physiological and behavioral changes that make the prevention of weight regain more difficult than either initial weight loss or the prevention of weight gain. Exercise is recommended for the prevention of weight regain by both governmental agencies and professional organizations. To date, the effectiveness of exercise recommendations for the prevention of weight regain has not been evaluated in a properly designed, adequately powered trial. Therefore, we will conduct a randomized trial to evaluate the effectiveness of 3 levels of exercise on the prevention of weight regain, in initially overweight and obese sedentary men and women. Participants will complete a 3 month weight loss intervention of decreased energy intake (EI) and increased exercise (100 min/week). Participants achieving clinically significant weight loss (≥ 5% of initial weight), will then be randomly assigned to 12 months of verified exercise at 3 levels (150, 225 or 300 min/week). This study will evaluate: 1) the effectiveness of 3 levels of exercise on the prevention of weight regain over 12 months subsequent to clinically significant weight loss (≥ 5%); 2) gender differences in weight regain in response to 3 levels of exercise; and 3) potential compensatory changes in daily physical activity (PA) and EI on weight regain in response to the 3 levels of exercise. The results of this investigation will provide information to develop evidence-based recommendations for the level of exercise associated with the prevention of weight regain.

Favorable modulation of benign breast tissue and serum risk biomarkers is associated with > 10 % weight loss in postmenopausal women

We conducted a phase II feasibility study of a 6-month behavioral weight loss intervention in postmenopausal overweight and obese women at increased risk for breast cancer and the effects of weight loss on anthropomorphic, blood, and benign breast tissue biomarkers. 67 women were screened by random peri-areolar fine-needle aspiration, 27 were registered and 24 participated in the interventional phase. The 24 biomarker evaluable women had a median baseline BMI of 34.2 kg/m(2) and lost a median of 11 % of their initial weight. Significant tissue biomarker modulation after the 6-month intervention was noted for Ki-67 (if restricted to the 15 women with any Ki-67 at baseline, p = 0.041), adiponectin to leptin ratio (p = 0.003); and cyclin B1 (p = 0.001), phosphorylated retinoblastoma (p = 0.005), and ribosomal S6 (p = 0.004) proteins. Favorable modulation for serum markers was observed for sex hormone-binding globulin (p < 0.001), bioavailable estradiol (p < 0.001), bioavailable testosterone (p = 0.033), insulin (p = 0.018), adiponectin (p = 0.001), leptin (p < 0.001), the adiponectin to leptin ratio (p < 0.001), C-reactive protein (p = 0.002), and hepatocyte growth factor (p = 0.011). When subdivided by <10 or >10 % weight loss, change in percent total body and android (visceral) fat, physical activity, and the majority of the serum and tissue biomarkers were significantly modulated only for women with >10 % weight loss from baseline. Some factors such as serum PAI-1 and breast tissue pS2 (estrogen-inducible gene) mRNA were not significantly modulated overall but were when considering only those with >10 % weight loss. In conclusion, a median weight loss of 11 % over 6 months resulted in favorable modulation of a number of anthropomorphic, breast tissue and serum risk and mechanistic markers. Weight loss of 10 % or more should likely be the goal for breast cancer risk reduction studies in obese women.