Biomedical subjects

Robert W Jeffery

Publications and source records attributed to Robert W Jeffery.

At least 19 recordsLinked to original sources

PubMed2006

Specific food intake, fat and fiber intake, and behavioral correlates of BMI among overweight and obese members of a managed care organization.

BACKGROUND: The study examined correlates of body mass index (BMI) in overweight and obese members of a managed care organization seeking treatment for obesity. It assessed intake of specific foods, dietary fat or fiber, and behaviors attempted to control weight. METHODS: Participants were 508 men and 1293 women who were > 18 years and had a self-reported BMI > 27.0. This paper reports analyses of baseline and 24-month follow-up data from a randomized weight-loss trial. Cross-sectional and prospective relationships between BMI and behaviors were examined with regression analyses controlling for age and education. RESULTS: At baseline, hamburger and beef consumption were associated with higher BMI for men; for women, hamburger, fried chicken, hot dog, bacon or sausage, egg, French fry, and overall fat consumption were associated with higher BMI, while eating high fiber cereal, fruit, and overall fiber intake were associated with lower BMI. Virtually all forms of weight control behavior were reported more often in heavier people. Subscribing to exercise magazines, however, was associated with lower BMI. Decreased fat intake and increased fruit/vegetable/fiber intake over the course of the study were associated with reductions in BMI at 24 months. CONCLUSION: The same behaviors that differentiate individuals with different body weight in the general population also differentiate between individuals of different body weights at the high end of the weight distribution. Educational efforts aimed at preventing weight gain and reducing obesity might benefit from focusing on specific foods known to be associated empirically with body weight and weight change over time.

Journal Article↗

PubMed2006

The relationship between prevalence and duration of weight loss strategies and weight loss among overweight managed care organization members enrolled in a weight loss trial.

BACKGROUND: Many adults in the United States report engaging in weight loss behaviors. The current study examined weight loss strategies among managed care organization members, to determine the prevalence and impact of weight loss behaviors in this population. We hypothesized that greater engagement in weight loss strategies would be associated with greater weight loss success. METHODS: Data were taken from Weigh-to-Be (WTB), a two-year weight loss trial (N = 1801, 72% female, mean age = 50.7 years, mean weight = 95.9 kg, mean BMI = 34.2 kg/m2). Every six months, participants completed a questionnaire assessing frequency and duration of weight loss strategies (calorie reduction, fat reduction, increased fruit/vegetable intake, increased exercise, elimination of sweets, consumption of less food). General linear models and structural equation methods were used to examine associations between weight loss strategy use and weight change over time. RESULTS: Weight loss strategy prevalence rates ranged from 68% to 76% over two years. For all dietary strategies, any use of the strategy between baseline and 24 months was associated with weight loss at 24 months; those who did not engage in the strategy showed weight gains during that period. Results of general linear models and structural equation models indicated that increased use of weight loss strategies was significantly associated with greater 24-month weight loss. CONCLUSION: The prevalence of weight loss strategies in this obese adult managed care population was quite high, and use of these strategies was associated in dose-response fashion with better weight loss. Future interventions may benefit from emphasis on persistence of similar strategies to achieve more successful outcomes.

Journal Article↗

PubMed2006

Are fast food restaurants an environmental risk factor for obesity?

OBJECTIVE: Eating at "fast food" restaurants has increased and is linked to obesity. This study examined whether living or working near "fast food" restaurants is associated with body weight. METHODS: A telephone survey of 1033 Minnesota residents assessed body height and weight, frequency of eating at restaurants, and work and home addresses. Proximity of home and work to restaurants was assessed by Global Index System (GIS) methodology. RESULTS: Eating at "fast food" restaurants was positively associated with having children, a high fat diet and Body Mass Index (BMI). It was negatively associated with vegetable consumption and physical activity. Proximity of "fast food" restaurants to home or work was not associated with eating at "fast food" restaurants or with BMI. Proximity of "non-fast food" restaurants was not associated with BMI, but was associated with frequency of eating at those restaurants. CONCLUSION: Failure to find relationships between proximity to "fast food" restaurants and obesity may be due to methodological weaknesses, e.g. the operational definition of "fast food" or "proximity", or homogeneity of restaurant proximity. Alternatively, the proliferation of "fast food" restaurants may not be a strong unique cause of obesity.

Journal Article↗

PubMed2006

The impact of self-efficacy on behavior change and weight change among overweight participants in a weight loss trial.

Despite considerable clinical interest, attempts to link perceived self-efficacy with successful weight control have had mixed success. Definitive data on prospective associations between self-efficacy and weight loss are particularly sparse. This study examined relationships between self-efficacy beliefs, weight control behaviors, and weight change among individuals participating in a weight loss trial (N = 349, 87% women). Cross-sectionally, eating and exercise self-efficacy beliefs were strongly associated with corresponding weight loss behaviors. Self-efficacy beliefs prospectively predicted weight control behavior and weight change during active treatment but not during follow-up. Mediational models indicate that people's weight control behaviors mediate the impact of self-efficacy on weight change.

Cross-Sectional Studies↗

PubMed2006

Specifying the determinants of the initiation and maintenance of behavior change: an examination of self-efficacy, satisfaction, and smoking cessation.

Using data from smokers (N = 591) who enrolled in an 8-week smoking cessation program and were then followed for 15 months, the authors tested the thesis that self-efficacy guides the decision to initiate smoking cessation but that satisfaction with the outcomes afforded by quitting guides the decision to maintain cessation. Measures of self-efficacy and satisfaction assessed at the end of the program, 2 months, and 9 months were used to predict quit status at 2, 9, and 15 months, respectively. At each point, participants were categorized as either initiators or maintainers on the basis of their pattern of cessation behavior. Across time, self-efficacy predicted future quit status for initiators, whereas satisfaction generally predicted future quit status for maintainers. Implications for models of behavior change and behavioral interventions are discussed.

Adolescent↗

PubMed2006

A satisfaction enhancement intervention for long-term weight loss.

OBJECTIVE: To compare the effects of two satisfaction enhancement interventions for weight control on behavioral and weight changes among individuals in a 15-month weight loss program. The primary hypothesis was that long-term weight loss would be improved by an intervention that enhances perceived satisfaction with achieved outcomes. RESEARCH METHODS AND PROCEDURES: Men and women (331) were randomized to weight control programs comprised of diet and exercise counseling and a cognitive intervention that emphasized either comparing experienced outcomes with expectation of ideal outcomes or comparing experienced outcomes with pretreatment status. The latter was expected to cause greater satisfaction with weight loss progress. RESULTS: The intervention manipulation was not successful in influencing cognitions, satisfaction, or weight change. DISCUSSION: The potential for intervening on satisfaction per se for the purpose of achieving greater or more sustained weight loss remains to be demonstrated.

Adult↗

PubMed2005

The association of gastrointestinal symptoms with weight, diet, and exercise in weight-loss program participants.

BACKGROUND & AIMS: Studies on the relationship between gastrointestinal (GI) symptoms and obesity are limited. Research on the relationship between GI symptoms (including irritable bowel syndrome [IBS]), weight, and weight-related behaviors are rare. This study assessed rates of GI symptoms in a sample of obese patients in a weight-loss program and explored relationships among GI symptoms and obesity, binge eating, dieting (fat and fruit/fiber consumption), and physical activity. METHODS: A total of 983 participants (70% women) had a mean body mass index (BMI) of 33.2+/-5.7 kg/m2 (range, 25.1-60.8 kg/m2) and a mean age of 52.7+/-12.4 years (range, 20.4-89.8 y). Participants completed a questionnaire about diet and physical activity and a standardized self-report Rome II questionnaire assessing IBS status and GI symptoms. RESULTS: In bivariate analyses BMI was associated positively with abdominal pain and diarrhea whereas healthier diet (lower fat and higher fruit/fiber intake) and higher physical activity were associated with fewer GI symptoms. In multivariate models BMI was not associated with GI symptoms; physical activity remained a protective factor. CONCLUSIONS: Although physiologic mechanisms still need to be explored, associations between GI symptoms and diet and exercise behaviors may have implications for the treatment of both obesity and GI symptoms.

Adult↗

PubMed2005

The effects of outcome expectations and satisfaction on weight loss and maintenance: correlational and experimental analyses--a randomized trial.

This study examines the hypothesis that highly favorable outcome expectations promote weight loss and hinder weight maintenance. To investigate the effects of outcome expectations and satisfaction with treatment outcomes on weight loss, 349 adults were randomly assigned to 1 of 2 weight loss programs that emphasize either (a) an "optimistic" message, focusing exclusively on the positive aspects of weight loss, or (b) a "balanced" message, giving equal time to positive and negative aspects of weight loss. Participants changed their weight loss cognitions in response to the intervention, but there was no significant difference between the intervention treatment groups in short-term or long-term (18-month) weight loss. Independent of treatment message, positive outcome expectations and satisfaction were both associated with weight loss.

Adolescent↗

PubMed2005

Amount of food group variety consumed in the diet and long-term weight loss maintenance.

OBJECTIVE: Decreases in variety of foods consumed within high-fat-dense food groups and increases in variety of foods consumed within low-fat-dense food groups are associated with lower energy intake and greater weight loss during obesity treatment and may assist with weight loss maintenance. This study examined food group variety in 2237 weight loss maintainers in the National Weight Control Registry, who had lost 32.2 +/- 18.0 kg (70.9 +/- 39.5 lbs) and maintained a weight loss of at least 13.6 kg (30 lbs) for 6.1 +/- 7.7 years. RESEARCH METHODS AND PROCEDURES: At entry into the registry, registry members completed a food frequency questionnaire from which amount of variety consumed from different food groups was assessed. To provide a context for interpreting the level of variety occurring in the diet of registry participants, food group variety was compared between registry participants and 96 individuals who had recently participated in a behavioral weight loss program and had lost at least 7% of initial body weight. RESULTS: Registry members reported consuming a diet with very low variety in all food groups, especially in those food groups higher in fat density. Registry participants consumed significantly (p < 0.001) less variety within all food groups, except fruit and combination foods, than recent weight losers after 6 months of weight loss treatment. DISCUSSION: These results suggest that successful weight loss maintainers consume a diet with limited variety in all food groups. Restricting variety within all food groups may help with consuming a low-energy diet and maintaining long-term weight loss.

Adult↗

PubMed2005

Self-weighing in weight gain prevention and weight loss trials.

BACKGROUND: Although self-monitoring is a central tenet of behavioral approaches to changing health behavior, clinical and public health recommendations for better controlling body weight do not emphasize weight self-monitoring. PURPOSE: The objective was to determine whether more frequent self-weighing exerts a positive influence on weight loss or weight gain prevention. METHODS: This study examined cross-sectional and longitudinal associations between self-weighing frequency and weight in two distinct groups: 1,226 adults who were enrolled in a weight gain prevention trial, and 1,800 adults who were enrolled in a weight loss trial. RESULTS: Although the samples differed significantly in weight and baseline demographic characteristics, the distribution of baseline weighing frequencies did not differ by study. In both groups, more frequent self-weighing at baseline was associated with greater age, lower fat intake, White ethnicity, current nonsmoking status, a greater history of dieting to lose weight, and lower current body mass index. Despite similar weighing instructions, differential patterns of weighing frequency over time were observed: Weight loss dieters increased weighing over time regardless of treatment group (control or intervention), whereas weight gain preventers decreased weighing over time in the control group and increased weighing over time in intervention groups. Most important, higher weighing frequency was associated with greater 24-month weight loss or less weight gain. CONCLUSIONS: Results support the idea that daily weighing is valuable to individuals trying to lose weight or prevent weight gain. Daily self-weighing should be emphasized in clinical and public health messages about weight control. Experimental studies on the effects of weighing frequency in these contexts are recommended.

Adult↗

PubMed2004

Predictors of vigorous exercise adoption and maintenance over four years in a community sample.

BACKGROUND: Very little is known about the correlates of adoption and maintenance of vigorous exercise. The purpose of this study was to understand the sociodemographic correlates of exercise adoption and maintenance in a community sample. METHODS: 917 women and 229 men completed annual surveys as part of a community-based weight gain prevention trial over four years. Multivariate regressions evaluated predictive factors for maintenance of vigorous exercise over time in regular exercisers, and predictors of adoption of exercise in adults who were sedentary at baseline. RESULTS: Exercise maintenance at Years 2 and 3 was associated with ethnicity and exercise level at baseline, while exercise maintenance at Year 4 was associated with television watching, BMI and exercise at baseline. Exercise level at baseline was associated with exercise initiation at Year 2 and Year 3. Income level, marital status, and smoking status predicted exercise initiation at Year 4. CONCLUSIONS: Predictors of vigorous exercise maintenance were more consistent than predictors of vigorous exercise initiation. Results suggest that those who adopt vigorous exercise are a heterogeneous group and intervention messages could be more broadly focused. These data also suggest that exercise maintenance interventions should continue to target low-income populations with messages regarding smoking, weight and television. Clearly further research is needed to understand the factors that contribute to exercise initiation and maintenance, and to develop effective interventions to improve levels of physical activity levels.

Journal Article↗

PubMed2004

How can Health Behavior Theory be made more useful for intervention research?

BACKGROUND: The present paper expresses the author's views about the practical utility of Health Behavior Theory for health behavior intervention research. The views are skeptical and perhaps even a bit exaggerated. They are, however, also based on 20-plus years of in-the-trenches research focused on improving health behavior practice through research. DISCUSSION: The author's research has been theoretically driven and has involved measurement of varying variables considered to be important theoretical mediators and moderators of health behavior. Regretfully, much of this work has found these variables wanting in basic scientific merit. Health Behavior Theory as we have known it over the last 25 years or so has been dominated by conceptualizations of behavior change processes that highlight cognitive decision-making. Although much of health behavior practice targets what people do rather than what they think, the logic of focusing on thoughts is that what people think about is the key to what they will do in the future, and that interventions that can measure and harness those processes will succeed to a greater extent than those that do not. Unfortunately, in the author's experience, the premise of cognitive theories has fallen short empirically in a number of ways. The cognitive schemata favored by most health behavior theories are difficult to measure, they do not predict behavioral outcomes very well, there is little evidence that they cause behavior, and they are hard to change directly. SUMMARY: It is suggested that health behavior researchers reconsider their use of these theories in favor of models whose variables are more accessible to observation and experimental manipulation and that most importantly have strong empirical support.

Journal Article↗

PubMed2004

Are unrealistic weight loss goals associated with outcomes for overweight women?

OBJECTIVE: To examine cross-sectional correlates of current, goal, and dream weight and their prospective associations with weight loss in treatment. RESEARCH METHODS AND PROCEDURES: Goal and dream weights, demographic characteristics, and psychosocial factors were assessed by self-report questionnaire in 302 adult women enrolled in a weight loss trial. Height and weight were assessed at baseline, after 8 weeks of active treatment, and at 6- and 18-month follow-up. Regression techniques examined associations among baseline, goal, and dream weights, psychosocial factors, and treatment outcomes. RESULTS: On average, goal and dream weight losses were unrealistically high (-24% and -30%, respectively). High goals were associated with greater expected effort and greater expected reward but were not associated with psychological distress. Goal and dream weight losses were only weakly associated with behavioral or weight outcomes. An association between higher dream weight losses and greater weight loss at 18 months was the only outcome result to reach statistical significance. DISCUSSION: Results suggest that lack of realism in weight loss goals is not important enough to justify counseling people to accept lower weight loss goals when trying to lose weight.

Adolescent↗

PubMed2004

Is dietary fat intake related to liking or household availability of high- and low-fat foods?

OBJECTIVE: Despite the increasing availability of low- and reduced-fat foods, Americans continue to consume more fat than recommended, which may be a contributing factor to the obesity epidemic. This investigation examined relationships between liking and household availability of high- and low-fat foods and their association with dietary fat intake. RESEARCH METHODS AND PROCEDURES: A food frequency questionnaire assessed percent calories from fat consumed over the past year in 85 men and 80 women. Participants reported their degree of liking 22 "high-fat foods" (>45% calories from fat) and 22 "low-fat foods" (<18% calories from fat), and the number and percentage (number of high- or low-fat foods/total number of foods x 100) of these high- and low-fat foods in their homes. RESULTS: Hierarchical regression analyses examined the ability of liking and household availability of low- and high-fat foods to predict percent dietary fat intake. After controlling for age, sex, and BMI, liking ratings for high- and low-fat foods and the interaction of liking for low-fat foods by the percentage of low-fat foods in the household were significant predictors of percent dietary fat consumed. Greater liking of high-fat foods and lower liking of low-fat foods, both alone and combined with a lower percentage of low-fat foods in the home, were predictive of higher dietary fat intake. DISCUSSION: Interventions designed to reduce dietary fat intake should target both decreasing liking for high-fat foods and increasing liking for low-fat foods, along with increasing the proportion of low-fat foods in the household.

Adult↗

PubMed2004

The weight loss experience: a descriptive analysis.

BACKGROUND: Six months of loss followed by gradual regain to baseline is descriptive of most weight loss attempts. PURPOSE: This study sought to identify thoughts and feelings accompanying weight loss that might explain the phenomenon. METHODS: Thoughts, feelings, and body weight were measured weekly for 6 months in 41 women receiving behavioral treatment for obesity. RESULTS: Overall, the weight loss experience of these women was positive, requiring modest time and effort and being associated with more positive than negative thoughts and experiences. Over time, however, positive but not negative reactions to the weight loss experience decreased, as did the strength of beliefs that the benefits of weight loss were worth the effort. In addition, we found no relation between the women's perception of effort and weight loss results. CONCLUSIONS: Inadequate long-term rewards for behaviors needed for weight control may be an important cause of frequent weight loss failures.

Adult↗

PubMed2004

Recruitment to mail and telephone interventions for obesity in a managed care environment: the Weigh-To-Be project.

OBJECTIVE: To evaluate the success of mail- and telephone-based weight loss programs in recruiting a representative sample of overweight members of a managed care organization (MCO). STUDY DESIGN: Cross-sectional. PATIENTS AND METHODS: A total of 1801 members of an MCO were recruited by direct mail, clinic flier, and physician referral for a research study evaluating mail- and telephone-based weight loss programs; 412 additional overweight members of the same MCO were identified in a general member survey for comparison purposes. Body mass index, demographics, diet, and exercise habits were measured. RESULTS: Study volunteers were heavier, more likely to be women, more likely to be minorities, more educated, and younger than the general sample of overweight members. They also had a more extensive history of dieting, ate a diet higher in fat and lower in fruit and vegetables, and were more likely to report binge eating than the general sample. However, study volunteers reported a higher level of physical activity. CONCLUSIONS: Invitations to participate in weight loss programs can attract large numbers of people in a managed care setting. However, the participation bias in recruitment to such programs is similar to that seen in traditional face-to-face interventions. Women of higher socioeconomic status who are severely obese and who have an extensive history of weight control efforts are more likely to participate. Additional research is needed to find ways to reach more men and older adults.

Adult↗

PubMed2003

Relationships between perceived stress and health behaviors in a sample of working adults.

The study examined associations between perceived stress and fat intake, exercise, alcohol consumption, and smoking behaviors. Data were from surveys of 12,110 individuals in 26 worksites participating in the SUCCESS project (D. J. Hennrikus, R. W. Jeffery, & H. A. Lando, 1995), a study of smoking cessation interventions. Linear regression analyses examined cross-sectional associations between stress level and health behaviors. Analyses were stratified by gender and controlled for demographics. High stress for both men and women was associated with a higher fat diet, less frequent exercise, cigarette smoking, recent increases in smoking, less self-efficacy to quit smoking, and less self-efficacy to not smoke when stressed. Stress was not associated with alcohol intake. Findings suggest that the association between stress and disease may be moderated in part by unhealthy behaviors.

Adult↗

PubMed2003

The changing environment and population obesity in the United States.

The recent unexpected increases in the prevalence of obesity in the United States are widely agreed to be the result of changes in environmental conditions. This paper reviews the available data from diverse sources on environmental factors and obesity. Coverage includes descriptive data on temporal trends in the environment, cross-sectional and longitudinal studies of the association between environmental exposures and body weight, and experimental trials that have related environmental factors thought to be potentially important in influencing energy intake and expenditure and body weight. Over the period covered by the "obesity epidemic," a variety of environmental factors have changed dramatically. Some would seem to favor increased body weight (e.g., increased availability of convenience foods and increased use of automobiles and televised entertainment), and others would seem to favor decreased body weight (e.g., a lower-fat food supply and the increased availability of some forms of physical activity). Definitive conclusions about the relative contributions of energy intake and expenditure to increasing body weight or about the contribution of specific environmental exposures to increasing body weight are far from clear. Increased sophistication in methods for making valid inferences from existing environmental data would be helpful. Even more important, given the urgency of the problem, is experimental research on the question of what environmental changes would be necessary to reverse the obesity epidemic.

Environment↗