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ABSTRACT: Severe obesity (body mass index [BMI] ≥40 kg/m(2)) is a serious public health concern. Although bariatric surgery is an efficacious treatment approach, it is limited in reach; thus, nonsurgical treatment alternatives are needed. We examined the 4-year effects of an intensive lifestyle intervention on body weight and cardiovascular disease risk factors among severely obese, compared with overweight (25 ≤BMI <30), class I (30 ≤BMI <35), and class II obese (35 ≤BMI <40) participants.
There were 5145 individuals with type 2 diabetes (45-76 years, BMI ≥25 kg/m(2)) randomized to an intensive lifestyle intervention or diabetes support and education. The lifestyle intervention group received a behavioral weight loss program that included group and individual meetings, a ≥10% weight loss goal, calorie restriction, and increased physical activity. Diabetes support and education received a less intense educational intervention. Four-year changes in body weight and cardiovascular disease risk factors were assessed.
Across BMI categories, 4-year changes in body weight were significantly greater in lifestyle participants compared with diabetes support and education (Ps <.05). At year 4, severely obese lifestyle participants lost 4.9%±8.5%, which was similar to class I (4.8%±7.2%) and class II obese participants (4.4%±7.6%), and significantly greater than overweight participants (3.4%±7.0%; P <.05). Four-year changes in low-density-lipoprotein cholesterol, triglycerides, diastolic blood pressure, HbA(1c), and blood glucose were similar across BMI categories in lifestyle participants; however, the severely obese had less favorable improvements in high-density-lipoprotein cholesterol (3.1±0.4 mg/dL) and systolic blood pressure (-1.4±0.7 mm Hg) compared with the less obese (Ps <.05).
Lifestyle interventions can result in important long-term weight losses and improvements in cardiovascular disease risk factors among a significant proportion of severely obese individuals.
The American journal of medicine 03/2013; 126(3):236-242.e2. · 4.47 Impact Factor
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ABSTRACT: The importance of physical activity in weight management is widely documented. Although accelerometers offer an objective measure of activity that provide a valuable tool for intervention research, considerations for processing these data need further development.
This study tests the effects of using different criteria for accelerometry data reduction.
Data were obtained from 2,240 overweight and obese individuals with type 2 diabetes mellitus (T2DM) from the Look AHEAD study, with 2,177 baseline accelerometer files used for analysis. Number, duration, and intensity of moderate (≥3 metabolic equivalents (METS)) and vigorous (≥6 METS) activity bouts were compared using various data reduction criteria. Daily wear time was identified as 1,440 min/day minus non-wear time. Comparisons of physical activity patterns for non-wear time (using either 20, 30, or 60 min of continuous zeros), minimal daily wear time (8, 10, and 12 h), number of days with available data (4, 5, and 6 days), weekdays vs. weekends, and 1- or 2-min time interruptions in an activity bout were performed.
In this mostly obese population with T2DM (BMI = 36.4 kg/m(2) ; mean age = 59.0 years), there were minimal differences in physical activity patterns using the different methods of data reduction. Altering criteria led to differences in the number of available data (sample size) meeting specific criteria.
Although our results are likely directly applicable only to obese individuals with T2DM, an understudied population with regards to physical activity, the systematic analysis for data reduction employed can be more generalizable and provide guidance in this area in the absence of standard procedures.
Obesity 01/2013; 21(1):32-44. · 4.28 Impact Factor
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John M Jakicic,
Caitlin M Egan,
Anthony N Fabricatore,
Sarah A Gaussoin,
Stephen P Glasser,
Louise A Hesson,
William C Knowler,
Wei Lang,
Judith G Regensteiner,
Paul M Ribisl,
Donna H Ryan
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ABSTRACT: OBJECTIVE
To examine an intensive lifestyle intervention (ILI) compared with diabetes support and education (DSE) on 4-year change in fitness and physical activity (PA), and to examine the effect of change in fitness and PA, adjusting for potential confounders, on glycemic control in the Look AHEAD Trial.RESEARCH DESIGN AND METHODS
Subjects were overweight/obese adults with type 2 diabetes mellitus (T2DM) with available fitness data at 4 years (n = 3,942).This clinical trial randomized subjects to DSE or ILI. DSE received standard care plus information three times per year related to diet, PA, and social support. ILI received weekly intervention contact for 6 months that was reduced over the 4-year period and was prescribed diet and PA. Measures included weight, fitness, PA, and HbA(1c).RESULTSThe difference in percent fitness change between ILI and DSE at 4 years was significant after adjustment for baseline fitness and change in weight (3.70 vs. 0.94%; P < 0.01). At 4 years, PA increased by 348 (1,562) kcal/week in ILI vs. 105 (1,309) kcal/week in DSE (P < 0.01). Fitness change at 4 years was inversely related to change in HbA(1c) after adjustment for clinical site, treatment, baseline HbA(1c), prescribed diabetes medication, baseline fitness, and weight change (P < 0.01). Change in PA was not related to change in HbA(1c).CONCLUSIONSA 4-year ILI increased fitness and PA in overweight/obese individuals with T2DM. Change in fitness was associated with improvements in glycemic control, which provides support for interventions to improve fitness in adults with T2DM.
Diabetes care 12/2012; · 8.09 Impact Factor
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ABSTRACT: Background: Because lifestyle-induced improvements in cardiovascular risk factors vary substantially across individuals with type 2 diabetes, we investigated the extent to which increases in fitness explain cardiovascular risk factor improvements independent of weight loss in a lifestyle intervention.Methods: We studied 1-year changes in Look AHEAD, a randomized trial comparing an intensive lifestyle intervention (ILI) to a diabetes support and education (DSE) control group in adults with type 2 diabetes. Assessments included weight, fitness, blood pressure (BP), glucose, HbA1c, and lipids. We evaluated the effects of changes in weight and fitness on changes in cardiovascular risk factors by study arm, using R(2) from multiple linear regression.Results: Analyses included participants with fitness data at baseline and 1-year (n = 4408; 41% male, 36% non-white; mean age 58.7 ± 6.8 years). Weight change alone improved R(2) for explaining changes in risk factors up to 8.2% in ILI and 1.7% in DSE. Fitness change alone improved R(2) up to 3.9% in ILI and 0.8% in DSE. After adjusting for weight change, fitness was independently associated (p < 0.05) with improvements in R(2 )for glucose (+0.7%), HbA1c (+1.1%), high-density lipoprotein (HDL) cholesterol (+0.4%), and triglycerides (+0.2%) in ILI and diastolic BP (+0.3%), glucose (+0.3%), HbA1c (+0.4%), and triglycerides (+0.1%) in DSE. Taken together, weight and fitness changes explained from 0.1-9.3% of the variability in cardiovascular risk factor changes.Conclusion: Increased fitness explained statistically significant but small improvements in several cardiovascular risk factors beyond weight loss. Further research identifying other factors that explain cardiovascular risk factor change is needed.
European journal of preventive cardiology. 09/2012;
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ABSTRACT: Given that bariatric surgery (BS) and lifestyle intervention (LI) represent two vastly different approaches to treating severe obesity, there is growing interest in whether individuals who seek BS versus LI also differ on weight-related behaviors. In the present study, we compared BS- and LI-seekers on physical activity (PA) and sedentary behaviors (SB), and examined between-group differences in health-related quality of life (HRQoL), while controlling for PA.
A sample of 34 LI-seekers were matched with 34 BS-seekers on gender, age, BMI, and PA monitor-daily wear time (age: 42.1±10.0 years; BMI: 45.6±6.5 kg/m2). PA and SB were assessed over a 7-day period via the SenseWear Armband (SWA). HRQoL was measured using the SF-36, with scores standardized to a population normal distribution (M=50, SD=10). Participants wore the SWA for 13.7±1.6 h/day. BS-seekers did not differ from LI-seekers on average min/d over the wear period spent in SB (641±117.1 vs. 638.4±133.4, p=0.62) or light (136.4±76.1 vs. 145.5±72.5, p=0.59) and moderate-to-vigorous (>1-min bouts=36.4±26.2 vs. 40.2±31.3, p=0.59; ≥10-min bouts=5.7±8.3 vs. 10.2±17.0, p=0.17) PA. BS-seekers reported significantly lower SF-36 physical functioning (42.4±10.9 vs. 49.0±6.8, p=0.004) and physical component summary (43.9±10.1 vs. 48.9±7.0) scores versus LI-seekers. BS-seeker group status was related to lower physical functioning (β=0.30, p=0.009), independent of gender, age, BMI, and daily PA.
Findings suggest that seeking BS versus LI is not related to patterns of PA or SB, and that lower subjective physical functioning is not associated with lower overall PA levels in BS-seekers.
Health and Quality of Life Outcomes 07/2012; 10:86. · 2.11 Impact Factor
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ABSTRACT: Given the obesity epidemic, effective but resource-efficient weight loss treatments are needed. Stepped-treatment approaches customize interventions based on milestone completion and can be more effective while costing less to administer than conventional treatment approaches.
To determine whether a stepped-care weight loss intervention (STEP) compared with a standard behavioral weight loss intervention (SBWI) would result in greater weight loss.
A randomized clinical trial of 363 overweight and obese adults (body mass index: 25-<40; age: 18-55 years, 33% nonwhite, and 83% female) who were randomized to SBWI (n = 165) or STEP (n = 198) at 2 universities affiliated with academic medical centers in the United States (Step-Up Study). Participants were enrolled between May 2008 and February 2010 and data collection was completed by September 2011.
All participants were placed on a low-calorie diet, prescribed increases in physical activity, and attended group counseling sessions ranging from weekly to monthly during an 18-month period. The SBWI group was assigned to a fixed program. Counseling frequency, type, and weight loss strategies could be modified every 3 months for the STEP group in response to observed weight loss as it related to weight loss goals.
Mean change in weight over 18 months. Additional outcomes included resting heart rate and blood pressure, waist circumference, body composition, fitness, physical activity, dietary intake, and cost of the program.
Of the 363 participants randomized, 260 (71.6%) provided a measure of mean change in weight over 18 months. The 18-month intervention resulted in weight decreasing from 93.1 kg (95% CI, 91.0 to 95.2 kg) to 85.6 kg (95% CI, 83.4 to 87.7 kg) (P < .001) in the SBWI group and from 92.7 kg (95% CI, 90.8 to 94.6 kg) to 86.4 kg (95% CI, 84.5 to 88.4 kg) in the STEP group (P < .001). The percentage change in weight from baseline to 18 months was -8.1% (95% CI, -9.4% to -6.9%) in the SBWI group (P < .001) compared with -6.9% (95% CI, -8.0% to -5.8%) in the STEP group (P < .001). Although the between-group difference in 18-month weight loss was not statistically different (-1.3 kg [95% CI, -2.8 to 0.2 kg]; P = .09), there was a significant group × time interaction effect (P = .03). The cost per participant was $1357 (95% CI, $1272 to $1442) for the SBWI group vs $785 (95% CI, $739 to $830) for the STEP group (P < .001). Both groups had significant and comparable improvements in resting heart rate, blood pressure level, and fitness.
Among overweight and obese adults, the use of SBWI resulted in a greater mean weight loss than STEP over 18 months. Compared with SBWI, STEP resulted in clinically meaningful weight loss that cost less to implement.
clinicaltrials.gov Identifier: NCT00714168.
JAMA The Journal of the American Medical Association 06/2012; 307(24):2617-26. · 30.03 Impact Factor
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ABSTRACT: Obesity increases cardiovascular disease risk and adversely affects vascular structure and function. Few studies have evaluated the vascular effects of non-surgical weight reduction in the severely obese. We hypothesized that weight loss and improvements in cardiometabolic factors would reduce common carotid artery intima-media thickness (CIMT) and inter-adventitial diameter (AD) in severely obese adults.
We performed carotid ultrasound and measured cardiometabolic factors in 90 severely obese participants (body mass index (BMI)≥35kg/m(2), age 30-55) at baseline and 6months in a randomized clinical trial of dietary intervention with (n=45) or without (n=45) physical activity.
The achieved weight loss (mean=8%) did not differ significantly by intervention group (P=0.10) and resulted in a 0.07mm mean decrease in AD (P=0.001). AD change was positively correlated with changes in BMI, waist circumference, abdominal visceral and subcutaneous fat, and body fat mass, and AD decreased more in men (P<0.05 for all). After multivariable adjustment, changes in BMI (P=0.03) and abdominal subcutaneous fat (P=0.04) were significant determinants of AD change. Although CIMT did not decrease significantly overall (-0.008mm, P=0.16), individuals who lost at least 5% of their body weight experienced a significant mean reduction in CIMT of 0.02mm (P=0.002). CIMT change was positively correlated with changes in BMI, waist circumference, fat-free mass, leptin, and insulin (P<0.05 for all). After multivariable adjustment, insulin reduction remained a significant determinant of CIMT decrease (P=0.03).
A 6 month intensive behavioral intervention can significantly reverse metabolic and vascular abnormalities in severely obese adults.
Metabolism: clinical and experimental 05/2012; 61(11):1589-97. · 2.59 Impact Factor
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Paul M Ribisl,
Sarah A Gaussoin,
Wei Lang,
Judy Bahnson,
Stephanie A Connelly,
Edward S Horton, John M Jakicic,
Tina Killean,
Dalane W Kitzman,
William C Knowler,
Kerry J Stewart,
Look Ahead Research Group
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ABSTRACT: The primary aims of this paper were (1) to evaluate the influence of intensive lifestyle weight loss and exercise intervention (ILI) compared with diabetes support and education (DSE) upon Heart Rate Recovery (HRR) from graded exercise testing (GXT) and (2) to determine the independent and combined effects of weight loss and fitness changes upon HRR. In 4503 participants (45-76 years) who completed 1 year of intervention, HRR was measured after a submaximal GXT to compare the influence of (ILI) with (DSE) upon HRR. Participants assigned to ILI lost an average 8.6% of their initial weight versus 0.7% in DSE group (P < 0.001) while mean fitness increased in ILI by 20.9% versus 5.8% in DSE (P < 0.001). At Year 1, all exercise and HRR variables in ILI improved (P < 0.0001) versus DSE: heart rate (HR) at rest was lower (72.8 ± 11.4 versus 77.7 ± 11.7 b/min), HR range was greater (57.7 ± 12.1 versus 53.1 ± 12.4 b/min), HR at 2 minutes was lower (89.3 ± 21.8 versus 93.0 ± 12.1 b/min), and HRR was greater (41.25 ± 22.0 versus 37.8 ± 12.5 b/min). Weight loss and fitness gain produced significant separate and independent improvements in HRR.
Journal of obesity 01/2012; 2012:309196.
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Faina Linkov,
G Larry Maxwell,
Ashley S Felix,
Yan Lin,
Diana Lenzner,
Dana H Bovbjerg,
Anna Lokshin,
Meredith Hennon, John M Jakicic,
Bret H Goodpaster,
James P DeLany
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ABSTRACT: Obesity is a major risk factor for the development of endometrial cancer (EC). An improved understanding of biologic mechanisms associated with weight loss, including alteration in inflammation, hormonal balance, and cancer antigens expression may lead to the development of effective cancer prevention strategies. The goal of this study was to explore longitudinal biomarker changes in obese women who underwent weight loss intervention, testing the hypothesis biomarker levels can be altered through intentional weight loss.
Serum samples from 89 participants with Class II and Class III obesity and 43 non morbidly obese comparisons were obtained in Re-Energize with Nutrition, Exercise and Weight Loss (RENEW) study as previously reported. Twenty-one bead-based xMAP immunoassays were utilized, including cancer-associated antigens, cytokines, chemokines, and hormones. One-way repeated measures ANOVA was used to examine the association between changes in biomarker expression levels over time (baseline, 6 months and 12 months). Linear mixed effects models were used to examine longitudinal relationships between biomarker expression levels.
Mean levels of VEGF, soluble E-selectin, GH, adiponectin, IL-6, IL-7, CA-125, and IGFBP-1 significantly differed between time periods. In adjusted mixed linear models, decreasing BMI was significantly associated with lower levels of soluble E-selectin and IL-6 and increases in GH, adiponectin, and IGFBP-1.
This is one of the first efforts to explore changes in cancer-associated biomarkers in a cohort of weight loss research participants at high risk for EC development. Our findings demonstrate that changes in the expression of markers can be achieved with weight loss intervention.
Gynecologic Oncology 12/2011; 125(1):114-9. · 3.89 Impact Factor
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ABSTRACT: Physical activity seems to be an important component of lifestyle interventions for weight loss and maintenance. Although the effects of physical activity on weight loss may seem to be modest, there seems to be a dose-response relationship between physical activity and weight loss. Physical activity also seems to be a critically important behavior to promote long-term weight loss and the prevention of weight regain. The benefits of physical activity on weight loss are also observed in patients with severe obesity (BMI ≥ 35 kg/m²) and in patients who have undergone bariatric surgery. Moreover, independent of the effect of physical activity on body weight, engagement in physical activity that results in improved cardiorespiratory fitness can contribute to reductions in health risk in overweight and obese adults. Thus, progression of overweight and obese patients to an adequate dose of physical activity needs to be incorporated into clinical interventions for weight control.
The Psychiatric clinics of North America 12/2011; 34(4):829-40. · 1.87 Impact Factor
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ABSTRACT: Purpose: Little is known about limitations in physical function across BMI categories in middle aged women using both self-report and performance-based measures. Furthermore, the impact of BMI on the measurement of function has not been explored. The purpose of this study was to assess physical function in adult women across BMI categories using self-report and performance-based measures and determine the influence of BMI on the relationship between the measures. Methods: Fifty sedentary females (10 in each BMI category: normal weight, overweight, obese class I, II, and III) aged 51.2 ± 5.4 years participated. Assessments included demographics, past medical history, physical activity level, BMI, and self-report (Late Life Function and Disability Instrument) and performance-based measures of physical function (6-Minute Walk Test, timed chair rise, gait speed). Physical function was compared between BMI categories using analysis of variance. The influence of BMI on the relationship of self-report and performance-based measures was analyzed using linear regression. Results: Compared to those that were normal weight or overweight, individuals with obesity scored lower on the self-report measure of physical function (LLFDI) for capability in participating in life tasks and ability to perform discrete functional activities. On the performance-based measures, the individuals with obesity had slower gait speed compared to the normal and overweight weight groups. For the 6-Minute Walk Test and timed chair stands, individuals with obesity had poorer performance compared to those who were normal weight. Linear regression analyses revealed that BMI attenuated the relationship between the self-report and performance-based measures by approximately 50%. Conclusions: While those with severe obesity were most impaired, adult women with less severe obesity also demonstrated significant decrements in physical function.
Cardiopulmonary physical therapy journal. 09/2011; 22(3):11-20.
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ABSTRACT: Rates of severe obesity (BMI ≥40 kg/m(2)) are on the rise, and effective treatment options are needed. We examined the effect of an intensive lifestyle intervention (ILI) on weight loss, cardiovascular disease (CVD) risk, and program adherence in participants with type 2 diabetes who were severely obese compared with overweight (BMI 25 to <30 kg/m(2)), class I (BMI 30 to <35 kg/m(2)), and class II (BMI 35 to <40 kg/m(2)) obese participants.
Participants in the Action for Health in Diabetes (Look AHEAD) trial were randomly assigned to ILI or diabetes support and education (DSE). DSE participants received a less intense educational intervention, whereas ILI participants received an intensive behavioral treatment to increase physical activity (PA) and reduce caloric intake. This article focuses on the 2,503 ILI participants (age 58.6 ± 6.8 years).
At 1 year, severely obese participants in the ILI group lost -9.04 ± 7.6% of initial body weight, which was significantly greater (P < 0.05) than ILI participants who were overweight (-7.43 ± 5.6%) and comparable to class I (-8.72 ± 6.4%) and class II obese (-8.64 ± 7.4%) participants. All BMI groups had comparable improvements in fitness, PA, LDL cholesterol, triglycerides, blood pressure, fasting glucose, and HbA(1c) at 1 year. ILI treatment session attendance was excellent and did not differ among weight categories (severe obese 80% vs. others 83%; P = 0.43).
Severely obese participants in the ILI group had similar adherence, percentage of weight loss, and improvement in CVD risk compared with less obese participants. Behavioral weight loss programs should be considered an effective option for this population.
Diabetes care 08/2011; 34(10):2152-7. · 8.09 Impact Factor
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ABSTRACT: Objective quantification of physical activity (PA) is needed to understand PA and sedentary behaviors in bariatric surgery patients, yet it is unclear whether PA estimates produced by different monitors are comparable and can be interpreted similarly across studies.
We compared PA estimates from the Stayhealthy RT3 triaxial accelerometer (RT3) and the Sensewear Pro(2) Armband (SWA) at both the group and individual participant level. Bariatric surgery candidates were instructed to wear the RT3 and SWA during waking hours for 7 days. Participants meeting valid wear time requirements (≥4 days of ≥8 h/day) for both monitors were included in the analyses. Time spent in sedentary (<1.5 METs), light (1.5-2.9 METs), moderate-to-vigorous (MVPA; ≥3.0 METs), and total PA (TPA; ≥1.5 METs) according to each monitor was compared.
Fifty-five participants (BMI 48.4 ± 8.2 kg/m(2)) met wear time requirements. Daily time spent in sedentary (RT3 582.9 ± 94.3; SWA 602.3 ± 128.6 min), light (RT3 131.9 ± 60.0; SWA 120.6 ± 65.7 min), MVPA (RT3 25.9 ± 20.9; SWA 29.9 ± 19.5 min), and TPA (RT3 157.8 ± 74.5; SWA 150.6 ± 80.7 min) was similar between monitors (p > 0.05). While the average difference in TPA between the two monitors at the group level was 7.2 ± 64.2 min; the average difference between the two monitors for each participant was 45.6 ± 45.4 min. At the group level, the RT3 and SWA provide similar estimates of PA and sedentary behaviors; however, concordance between monitors may be compromised at the individual level.
Findings related to PA and sedentary behaviors at the group level can be interpreted similarly across studies when either monitor is used.
Obesity Surgery 08/2011; 22(3):347-52. · 3.29 Impact Factor
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ABSTRACT: Bariatric surgery candidates spend very little time in moderate-to-vigorous intensity physical activity (≥ 3 metabolic equivalents [METs]). This study examined (1) how much of their remaining time is spent in sedentary behaviors (SB < 1.5 METs) compared to light-intensity activities (1.5–2.9 METs) and (2) whether sedentary time varies by BMI.
Daily time (hours, %) spent in SB was examined in 42 surgery candidates (BMI = 49.5 ± 7.9 kg/m2) using the SenseWear Pro2 Armband. Participants were stratified by BMI to assess the relationship between degree of obesity and SB.
Participants wore the armband for 5.4 ± 0.7 days and 13.3 ± 1.7 h/day. On average, 81.4% (10.9 ± 2.1 h/day)of this time was spent in SB. Participants with BMI ≥ 50 spent nearly an hour more per day in SB than those with BMI 35–49.9 (p = 0.01).
Bariatric surgery candidates spend over 80%of their time in SB. Reducing SB may help to increase physical activity in these patients.
Obesity Surgery 06/2011; 21(6):811-4. · 3.29 Impact Factor
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John M Jakicic
American journal of preventive medicine 05/2011; 40(5):583-4. · 4.24 Impact Factor
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ABSTRACT: The purpose of this study was to compare a technology-based system, an in-person behavioral weight loss intervention, and a combination of both over a 6-month period in overweight adults. Fifty-one subjects (age: 44.2 ± 8.7 years, BMI: 33.7 ± 3.6 kg/m(2)) participated in a 6-month behavioral weight loss program and were randomized to one of three groups: standard behavioral weight loss (SBWL), SBWL plus technology-based system (SBWL+TECH), or technology-based system only (TECH). All groups reduced caloric intake and progressively increased moderate intensity physical activity. SBWL and SBWL+TECH attended weekly meetings. SBWL+TECH also received a TECH that included an energy monitoring armband and website to monitor energy intake and expenditure. TECH used the technology system and received monthly telephone calls. Body weight and physical activity were assessed at 0 and 6 months. Retention at 6 months was significantly different (P = 0.005) between groups (SBWL: 53%, SBWL+TECH: 100%, and TECH: 77%). Intent-to-treat (ITT) analysis revealed significant weight losses at 6 months in SBWL+TECH (-8.8 ± 5.0 kg, -8.7 ± 4.7%), SBWL (-3.7 ± 5.7 kg, -4.1 ± 6.3%), and TECH (-5.8 ± 6.6 kg, -6.3 ± 7.1%) (P < 0.001). Self-report physical activity increased significantly in SBWL (473.9 ± 800.7 kcal/week), SBWL+TECH (713.9 ± 1,278.8 kcal/week), and TECH (1,066.2 ± 1,371 kcal/week) (P < 0.001), with no differences between groups (P = 0.25). The TECH used in conjunction with monthly telephone calls, produced similar, if not greater weight losses and changes in physical activity than the standard in-person behavioral program at 6 months. The use of this technology may provide an effective short-term clinical alternative to standard in-person behavioral weight loss interventions, with the longer term effects warranting investigation.
Obesity 02/2011; 20(2):356-63. · 4.28 Impact Factor
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ABSTRACT: Lifestyle interventions have resulted in weight loss or improved physical fitness among individuals with obesity, which may lead to improved physical function. This prospective investigation involved participants in the Action for Health in Diabetes (Look AHEAD) trial who reported knee pain at baseline (n = 2,203). The purposes of this investigation were to determine whether an Intensive Lifestyle Intervention (ILI) condition resulted in improvement in self-reported physical function from baseline to 12 months vs. a Diabetes Support and Education (DSE) condition, and whether changes in weight or fitness mediated the effect of the ILI. Outcome measures included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, stiffness, and physical function subscales, and WOMAC summary score. ILI participants exhibited greater adjusted mean weight loss (s.e.) vs. DSE participants (-9.02 kg (0.48) vs. -0.78 kg (0.49); P < 0.001)). ILI participants also demonstrated more favorable change in WOMAC summary scores vs. DSE participants (β (s.e.) = -1.81 (0.63); P = 0.004). Multiple regression mediation analyses revealed that weight loss was a mediator of the effect of the ILI intervention on change in WOMAC pain, function, and summary scores (P < 0.001). In separate analyses, increased fitness also mediated the effect of the ILI intervention upon WOMAC summary score (P < 0.001). The ILI condition resulted in significant improvement in physical function among overweight and obese adults with diabetes and knee pain. The ILI condition also resulted in significant weight loss and improved fitness, which are possible mechanisms through which the ILI condition improved physical function.
Obesity 01/2011; 19(1):83-93. · 4.28 Impact Factor
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ABSTRACT: Few studies have been conducted that have examined the long-term effect of different doses of physical activity (PA) on weight change in overweight adults without a prescribed reduction in energy intake. This study examined the effect of different prescribed doses of PA on weight change, body composition, fitness, and PA in overweight adults. Two hundred seventy-eight overweight adults (BMI: 25.0-29.9 kg/m²; age: 18-55 years) with no contraindications to PA were randomized to one of three intervention groups for a period of 18 months. MOD-PA was prescribed 150 min/week and HIGH-PA 300 min/week of PA. Self-help group (SELF) was provided a self-help intervention to increase PA. There was no recommendation to reduce energy intake. MOD-PA and HIGH-PA were delivered in a combination of in-person and telephone contacts across 18 months. 18-month percent weight change was -0.7 ± 4.6% in SELF, -0.9 ± 4.7% in MOD-PA, and -1.2 ± 5.6% in HIGH-PA. Subjects were retrospectively grouped as remaining within ±3% of baseline weight (WT-STABLE), losing >3% of baseline weight (WT-LOSS), or gaining >3% of baseline weight (WT-GAIN) for secondary analyses. 18-month weight change was 0.0 ± 1.3% for WT-STABLE, +5.4 ± 2.6% for WT-GAIN, and -7.4 ± 3.6% for WT-LOSS. 18-month change in PA was 78.2 ± 162.6 min/week for WT-STABLE, 74.7 ± 274.3 for WT-GAIN, and 161.9 ± 252.6 min/week for WT-LOSS. The weight change observed in WT-LOSS was a result of higher PA combined with improved scores on the Eating Behavior Inventory (EBI), reflecting the adoption of eating behaviors to facilitate weight loss. Strategies to facilitate the maintenance of these behaviors are needed to optimize weight control.
Obesity 01/2011; 19(1):100-9. · 4.28 Impact Factor
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ABSTRACT: 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.
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.
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).
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.
Obesity Surgery 12/2010; 21(8):1243-9. · 3.29 Impact Factor
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ABSTRACT: This study examined the acute effect of a bout of walking on hunger, energy intake, and appetite-regulating hormones [acylated ghrelin and glucagon-like peptide-1 (GLP-1)] in 19 overweight/obese women (BMI: 32.5 ± 4.3 kg/m²). Subjects underwent two experimental testing sessions in a counterbalanced order: exercise and rest. Subjects walked at a moderate-intensity for approximately 40 min or rested for a similar duration. Subjective feelings of hunger were assessed and blood was drawn at 5-time points (pre-, post-, 30-, 60-, 120-min post-testing). Ad libitum energy intake consumed 1-2h post-exercise/rest was assessed and similar between conditions (mean ± standard deviation; exercise: 551.5 ± 245.1 kcal [2.31 ± 1.0 MJ] vs. rest: 548.7 ± 286.9 kcal [2.29 ± 1.2 MJ]). However, when considering the energy cost of exercise, relative energy intake was significantly lower following exercise (197.8 ± 256.5 kcal [0.83 ± 1.1 MJ]) compared to rest (504.3 ± 290.1 kcal [2.11 ± 1.2 MJ]). GLP-1 was lower in the exercise vs. resting condition while acylated ghrelin and hunger were unaltered by exercise. None of these variables were associated with energy intake. In conclusion, hunger and energy intake were unaltered by a bout of walking suggesting that overweight/obese individuals do not acutely compensate for the energy cost of the exercise bout through increased caloric consumption. This allows for an energy deficit to persist post-exercise, having potentially favorable implications for weight control.
Appetite 12/2010; 55(3):413-9. · 2.59 Impact Factor
