Nathan R Mitchell

University of Minnesota Duluth, Duluth, Minnesota, United States

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Publications (16)45.65 Total impact

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    ABSTRACT: Objective: Examine the effect of weekday exposure over six months to different lunch sizes on energy intake and body weight in a free-living sample of working adults. Design and Methods: Adults (n=233) were randomly assigned to one of three lunch size groups (400 kcal; 800 kcal; 1600 kcal) or to a no-free lunch control group for six months. Weight and energy intake were measured at baseline, and months 1, 3, and 6. Results: Lunch energy was significantly higher in the 800 and 1600 kcal groups compared to the 400 kcal group (p < 0.0001). Total energy was significantly higher for the 1600 kcal group compared to the 400 and 800 kcal groups (p = 0.02). Body weight change at six months did not significantly differ at the 5% level by experimental group (1600 kcal group: +1.1 kg (sd=0.44); 800 kcal group: -0.1 kg (sd=0.42); 400 kcal group: -0.1 kg (sd=0.43); control group: 1.1 (sd=0.42); p=.07). Weight gain over time was significant in the 1600 kcal box lunch group (p < 0.05). Conclusions: Weekday exposure for six months to a 1600 kcal lunch caused significant increases in total energy intake and weight gain.
    Obesity 02/2014; · 3.92 Impact Factor
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    ABSTRACT: Obesity prevention in children offers a unique window of opportunity to establish healthful eating and physical activity behaviors to maintain a healthful body weight and avoid the adverse proximal and distal long-term health consequences of obesity. Given that obesity is the result of a complex interaction between biological, behavioral, family-based, and community environmental factors, intervention at multiple levels and across multiple settings is critical for both short- and long-term effectiveness. The Minnesota NET-Works (Now Everybody Together for Amazing and Healthful Kids) study is one of four obesity prevention and/or treatment trials that are part of the Childhood Obesity Prevention and Treatment (COPTR) Consortium. The goal of the NET-Works study is to evaluate an intervention that integrates home, community, primary care and neighborhood strategies to promote healthful eating, activity patterns, and body weight among low income, racially/ethnically diverse preschool-age children. Critical to the success of this intervention is the creation of linkages among the settings to support parents in making home environment and parenting behavior changes to foster healthful child growth. Five hundred racially/ethnically diverse, two-four year old children and their parent or primary caregiver will be randomized to the multi-component intervention or to a usual care comparison group for a three-year period. This paper describes the study design, measurement and intervention protocols, and statistical analysis plan for the NET-Works trial.
    Contemporary clinical trials 10/2013; · 1.51 Impact Factor
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    ABSTRACT: The present research compared a self-report measure of usual eating behaviors with two laboratory-based behavioral measures of food reward and food preference. Eating behaviors were measured among 233 working adults. A self-report measure was the Three Factor Eating Questionnaire (TFEQ) Restraint, Disinhibition and Hunger subscales. Laboratory measures were the (RVF) and Explicit Liking (EL) and Implicit Wanting (IW) for high fat food. Outcome measures were body mass index (BMI), and energy intake measured using three 24-hour dietary recalls. Significant bivariate associations were observed between each of the eating behavior measures and energy intake, but only Disinhibition and Hunger were associated with BMI. Multiple regression results showed RVF and EL and IW predicted energy intake independent of the TFEQ scales but did not predict BMI. Laboratory and self-report measures capture unique aspects of individual differences in eating behaviors that are associated with energy intake.
    Appetite 10/2013; · 2.54 Impact Factor
  • Simone A French, Nathan R Mitchell, Peter J Hannan
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    ABSTRACT: To examine associations between television viewing, sugar-sweetened beverage consumption, eating out, physical activity, and body weight change over 1 year. Secondary data analysis from randomized intervention trial. Households in the community. Adults (n = 153) and adolescents (n = 72) from the same households. Households were randomized to a home-based obesity prevention intervention or to a no-intervention control group for a 1-year period. Self-reported television viewing (TV) hours, diet, and physical activity. Body mass index (BMI) computed from measured weight and height (primary outcome measure). Mixed-model regression. Among adolescents, a significant prospective association was observed between decreases in television viewing hours and lower BMI z score at 1-year follow-up (decreased TV hours: BMI z score mean = 0.65; no change or increase TV hours: BMI z score = 0.92; P < .02). No significant prospective associations were observed among adults. Reducing television viewing may be an effective strategy to prevent excess weight gain among adolescents.
    Journal of nutrition education and behavior 05/2012; 44(5):415-22. · 1.36 Impact Factor
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    ABSTRACT: U.S. adults are at unprecedented risk of becoming overweight or obese, and most scientists believe the primary cause is an obesogenic environment. Worksites provide an opportunity to shape the environments of adults to reduce obesity risk. The goal of this group-randomized trial was to implement a four-component environmental intervention at the worksite level to positively influence weight gain among employees over a two-year period. Environmental components focused on food availability and price, physical activity promotion, scale access, and media enhancements. Six worksites in a U.S. metropolitan area were recruited and randomized in pairs at the worksite level to either a two-year intervention or a no-contact control. Evaluations at baseline and two years included: 1) measured height and weight; 2) online surveys of individual dietary intake and physical activity behaviors; and 3) detailed worksite environment assessment. Mean participant age was 42.9 years (range 18-75), 62.6% were women, 68.5% were married or cohabiting, 88.6% were white, 2.1% Hispanic. Mean baseline BMI was 28.5 kg/m(2) (range 16.9-61.2 kg/m(2)). A majority of intervention components were successfully implemented. However, there were no differences between sites in the key outcome of weight change over the two-year study period (p = .36). Body mass was not significantly affected by environmental changes implemented for the trial. Results raise questions about whether environmental change at worksites is sufficient for population weight gain prevention. ClinicalTrials.gov: NCT00708461.
    International Journal of Behavioral Nutrition and Physical Activity 02/2012; 9:14. · 3.58 Impact Factor
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    ABSTRACT: OBJECTIVE: To investigate whether sex differences exist in the pattern of change in C-reactive protein (CRP) levels during weight loss, and whether the associations between weight change and CRP change differ by the types of anthropometric variables. DESIGN: Longitudinal, prospective analysis of subjects participating in an intentional weight loss trial (the Lose It For Ever: LIFE Study) followed-up for 30 months. SUBJECTS: A total of 212 healthy, obese men and women (age: 23-77 years, body mass index (BMI): 30-39 kg m(-2)) took part in this study. MEASUREMENTS: BMI, waist and hip circumferences, and waist-to-hip ratio, CRP and lifestyle variables repeatedly measured at baseline, 6, 12, 18 and 30-month follow-up. RESULTS: Weight change was J shaped with a nadir at 12 months in both men and women (P for month(2) <0.0001). CRP level was consistently higher in women than in men, but the differences were less prominent and were not statistically significant at 12- and 18-month follow-up. CRP changes between any two consecutive visits were significantly associated with changes in BMI during the same period in women. However, the associations between CRP changes and changes in waist or hip circumference were not as consistent, especially between 18- and 30-month follow-up when CRP significantly increased. The associations in men were generally similar among the different anthropometric measures. The association between changes in BMI and CRP was stronger in men than in women. CONCLUSION: BMI change generally correlated well with CRP changes in both men and women in the course of follow-up. Significant sex difference in CRP level at baseline diminished at 12- and 18-month follow-up, when both sexes had maintained the lost weight.
    International journal of obesity (2005) 05/2011; 35(5):684-91. · 5.22 Impact Factor
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    ABSTRACT: The purpose of the present study was to evaluate an intervention to prevent weight gain among households (HHs) in the community. Ninety HHs were randomized to intervention or control group for 1 year. Intervention consisted of six face-to-face group sessions, placement of a television (TV) locking device on all home TVs, and home-based intervention activities. Measures were collected in person at baseline and 1 year. Weight, height, eating behaviors, physical activity (PA), and TV viewing were measured among HH members ages ≥ 12 years. Follow-up rate at 1 year was 96%. No significant intervention effects were observed for change in HH BMI-z score. Intervention HHs significantly reduced TV viewing, snacks/sweets intake, and dollars per person spent eating out, and increased (adults only) PA and self-weighing frequency compared with control HHs. A 1 year obesity prevention intervention targeting entire HHs was effective in reducing TV viewing, snack/sweets intake and eating out purchases. Innovative methods are needed to strengthen the home food environment intervention component. Longer intervention durations also need to be evaluated.
    Obesity 01/2011; 19(10):2082-8. · 3.92 Impact Factor
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    Simone A French, Melanie Wall, Nathan R Mitchell
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    ABSTRACT: The present study examined income-related household food purchases among a sample of 90 households from the community. Annotated food purchase receipts were collected for a four-week period by the primary household shopper. Receipt food source and foods items were classified into specific categories, and food quantities in ounces were recorded by research staff. For home sources, a limited number of food/beverage categories were recorded. For eating out sources, all food/beverage items were recorded. Median monthly per person dollars spent and per person ounces purchased were computed. Food sources and food categories were examined by household income tertile. A community-based sample of 90 households. Higher income households spent significantly more dollars per person per month from both home and eating out sources compared with lower income households ($163 versus $100, p < .001). Compared with lower income households, higher income households spent significantly more home source dollars on both fruits/vegetables (21.5 versus 10.2, p < .001) and sweets/snacks (17.3 versus 8.3, p < .001), but did not differ on home dollars spent on sugar sweetened beverages (2.0 versus 1.7, p < .46). The proportion of home beverages that were sugar sweetened beverages was significantly higher among lower income households (45% versus 26%, p < .01). Within eating out sources, lower income households spent a significantly greater percent of dollars per person at carry out places (54% versus 37%, p < .01). No income differences were observed for dollars spent at discount grocery stores, small grocery stores or convenience stores. Higher income households spent more money on both healthy and less healthy foods from a wide range of sources. Lower income households spent a larger proportion of their eating out dollars at carry out places, and a larger proportion of their home beverage purchases were sugar sweetened beverages.
    International Journal of Behavioral Nutrition and Physical Activity 10/2010; 7:77. · 3.58 Impact Factor
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    ABSTRACT: Decrease in the level of high-density lipoprotein cholesterol (HDLC) has been observed in women who start dieting, but not in men. Patterns of HDLC change during intentional weight loss through 30-months of follow-up, and their association with changes in anthropometric measurements were examined in obese women (N = 112) and men (N = 100). Missing HDLC values at 6-, 12-, 18-, and 30-month follow-up (N = 16, 34, 55, and 50, respectively) due to dropout were imputed by multiple imputation. Mean ages and BMIs of subjects at baseline were 47.2 years and 34.8 kg/m(2) for women, and 50.4 years and 35.0 kg/m(2) for men. On average, participants lost weight steadily for 12 months, followed by slow regain. During the first 6 months, HDLC decreased significantly in women (-4.1 mg/dl, P = 0.0007), but not in men. Significant HDLC increases were observed in both men and women from 6- to 12-month follow-up. HDLC changes in women were positively associated with changes in hip circumference from baseline to 12-month independent of changes in triglycerides (TG), glucose, and insulin. Rapid decrease of predominantly subcutaneous fat in the femoral and gluteal area might be associated with HDLC decrease in women during initial weight loss.
    Obesity 09/2010; 19(2):429-35. · 3.92 Impact Factor
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    ABSTRACT: The results of an 18-month worksite intervention to prevent obesity among metropolitan transit workers are reported. Four garages in a major metropolitan area were randomized to intervention or control groups. Data were collected during the fall of 2005 prior to the start of the intervention and during the fall of 2007, after the intervention ended. Intervention program components at the garage included enhancement of the physical activity facilities, increased availability of and lower prices on healthy vending machine choices, and group behavioral programs. Mixed model estimates from cross-sectional and cohort samples were pooled with weights inverse to the variance of their respective estimates of the intervention effects. Measurement participation rates were 78% at baseline and 74% at follow-up. The intervention effect on garage mean BMI change was not significant (-0.14 kg/m(2)). Energy intake decreased significantly, and fruit and vegetable intake increased significantly in intervention garages compared to control garages. Physical activity change was not significant. Worksite environmental interventions for nutrition and physical activity behavior change may have limited impact on BMI among transit workers who spend most of their workday outside the worksite.
    Preventive Medicine 04/2010; 50(4):180-5. · 3.50 Impact Factor
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    ABSTRACT: To evaluate the effects of lowering prices and increasing availability on sales of healthy foods and beverages from 33 vending machines in 4 bus garages as part of a multicomponent worksite obesity prevention intervention. Availability of healthy items was increased to 50% and prices were lowered at least 10% in the vending machines in two metropolitan bus garages for an 18-month period. Two control garages offered vending choices at usual availability and prices. Sales data were collected monthly from each of the vending machines at the four garages. Increases in availability to 50% and price reductions of an average of 31% resulted in 10% to 42% higher sales of the healthy items. Employees were mostly price responsive for snack purchases. Greater availability and lower prices on targeted food and beverage items from vending machines was associated with greater purchases of these items over an 18-month period. Efforts to promote healthful food purchases in worksite settings should incorporate these two strategies.
    Journal of occupational and environmental medicine / American College of Occupational and Environmental Medicine 01/2010; 52 Suppl 1:S29-33. · 1.88 Impact Factor
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    ABSTRACT: Associations between hours worked per week and Body Mass Index (BMI), food intake, physical activity, and perceptions of eating healthy at work were examined in a sample of transit workers. Survey data were collected from 1086 transit workers. Participants reported hours worked per week, food choices, leisure-time physical activity and perceptions of the work environment with regard to healthy eating. Height and weight were measured for each participant. Multivariate linear and logistic regressions were conducted to examine associations between work hours and behavioral variables. Associations were examined in the full sample and stratified by gender. Transit workers working in the highest work hour categories had higher BMI and poorer dietary habits, with results differing by gender. Working 50 or more hours per week was associated with higher BMI among men but not women. Additionally, working 50 or more hours per week was significantly associated with higher frequency of accessing cold beverage, cold food, and snack vending machines among men. Working 40 or more hours per week was associated with higher frequency of accessing cold food vending machines among women. Reported frequency of fruit and vegetable intake was highest among women working 50 or more hours per week. Intake of sweets, sugar sweetened beverages, and fast food did not vary with work hours in men or women. Physical activity and perception of ease of eating healthy at work were not associated with work hours in men or women. Long work hours were associated with more frequent use of garage vending machines and higher BMI in transit workers, with associations found primarily among men. Long work hours may increase dependence upon food availability at the worksite, which highlights the importance of availability of healthy food choices.
    International Journal of Behavioral Nutrition and Physical Activity 01/2010; 7:91. · 3.58 Impact Factor
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    ABSTRACT: Health risks linked to obesity and the difficulty most have in achieving weight loss underscore the importance of identifying dietary factors that contribute to successful weight loss. This study examined the association between change in dietary energy density and weight loss over time. Subjects were 213 men and women with BMI of 30-39 kg/m2 and without chronic illness enrolled in 2004 in a randomized trial evaluating behavioral treatments for long-term weight loss. Subjects completed a 62-item food frequency questionnaire at baseline and at 6, 12, and 18 months. Pearson correlations between BMI and energy density (kcals/g of solid food) at baseline were not significantly different from zero (r = -0.02, p = 0.84). In a longitudinal analysis, change in energy density was strongly related to change in BMI. The estimated beta for change in BMI (kg/m2) of those in the quartile representing greatest decrease in energy density at 18 months compared to those in the quartile with the least was -1.95 (p = 0.006). The association was especially strong in the first six months (estimated beta = -1.43), the period with greatest weight loss (mean change in BMI = -2.50 kg/m2 from 0-6 months vs. 0.23 kg/m2 from 12-18 months) and the greatest contrast with respect to change in energy density. Decreased energy density predicted weight loss in this 18 month weight loss study. These findings may have important implications for individual dietary advice and public health policies targeting weight control in the general population.
    International Journal of Behavioral Nutrition and Physical Activity 09/2009; 6:57. · 3.58 Impact Factor
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    ABSTRACT: Accurate measurement of household food purchase behavior (HFPB) is important for understanding its association with household characteristics, individual dietary intake and neighborhood food retail outlets. However, little research has been done to develop measures of HFPB. The main objective of this paper is to describe the development of a measure of HFPB using annotated food purchase receipts. Households collected and annotated food purchase receipts for a four-week period as part of the baseline assessment of a household nutrition intervention. Receipts were collected from all food sources, including grocery stores and restaurants. Households (n = 90) were recruited from the community as part of an obesity prevention intervention conducted in 2007-2008 in Minneapolis, Minnesota, USA. Household primary shoppers were trained to follow a standardized receipt collection and annotation protocol. Annotated receipts were mailed weekly to research staff. Staff coded the receipt data and entered it into a database. Total food dollars, proportion of food dollars, and ounces of food purchased were examined for different food sources and food categories. Descriptive statistics and correlations are presented. A total of 2,483 receipts were returned by 90 households. Home sources comprised 45% of receipts and eating-out sources 55%. Eating-out entrees were proportionally the largest single food category based on counts (16.6%) and dollars ($106 per month). Two-week expenditures were highly correlated (r = 0.83) with four-week expenditures. Receipt data provided important quantitative information about HFPB from a wide range of sources and food categories. Two weeks may be adequate to reliably characterize HFPB using annotated receipts.
    International Journal of Behavioral Nutrition and Physical Activity 08/2009; 6:37. · 3.58 Impact Factor
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    ABSTRACT: OBJECTIVE: To examine the trajectories of mood, weight and physical activity, and associations between mood, weight, and gender, among 213 obese individuals. METHODS: Prospective, longitudinal design. Assessments at baseline and 6, 12, and 18 months of Profile of Mood States, Paffenbarger Physical Activity Questionnaire, and weight. RESULTS: Total mood disturbance decreased from baseline to 6 months, with no change thereafter. Weight decreased from baseline to 6 to 12 months, and increased from 12 to 18 months. Physical activity increased from baseline to 6 months, and 12 to 18 months. Increased physical activity predicted greater vigor and less fatigue over time. Females high in distress at 6 months lost less weight than females low in distress and at 18 months gained more weight than those low in distress. There were no such associations among males. CONCLUSION: The trajectories of mood, weight and physical activity were synchronous only in the short-term. Distress monitoring, targeted to females who relapse, may be warranted.
    Internet Journal of Mental Health 01/2009; 6(1).
  • Journal of The American Dietetic Association - J AMER DIET ASSN. 01/2009; 109(9).

Publication Stats

117 Citations
45.65 Total Impact Points

Institutions

  • 2010–2013
    • University of Minnesota Duluth
      • Department of Family Medicine and Community Health
      Duluth, Minnesota, United States
  • 2012
    • University of Minnesota Twin Cities
      • Division of Epidemiology and Community Health
      Minneapolis, MN, United States
  • 2009
    • University of Washington Seattle
      • School of Social Work
      Seattle, WA, United States