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Biomedical subjects

R R Wing

Publications and source records attributed to R R Wing.

At least 55 records · Page 3Linked to original sources
PubMed1999

Physical activity in the treatment of the adulthood overweight and obesity: current evidence and research issues.

PURPOSE: The purpose of this paper is to review the evidence on the role of physical activity in the treatment of adult overweight and obesity. Three specific questions are addressed: (1) Does exercise alone produce weight loss? (2) Does exercise in combination with diet produce greater weight loss than diet only? and (3) Does exercise in combination with diet produce better maintenance of weight loss than diet alone? METHODS: The literature initially identified by the Expert Panel on Clinical Guidelines for the Treatment of Obesity, three key meta analyses, and additional literature searches were used to identify randomized trials related to the three aforementioned topics. These articles were reviewed and tabulated. RESULTS: Six of 10 randomized studies found significantly greater weight loss in exercise alone versus no treatment controls. The magnitude of the effect averaged 1-2 kg. Only 2 of 13 studies found significant differences in initial weight loss for diet plus exercise versus diet only, although almost all studies pointed in this direction. Six studies were identified with maintenance periods of at least 1 yr. In two of the six there were significant long term differences favoring diet plus exercise, but in every study considered the direction of the difference favored diet plus exercise. Other strong evidence showing benefits of exercise for long-term weight loss comes from correlational analyses which consistently find that those individuals who report the greatest exercise have the best maintenance of weight loss. CONCLUSIONS: Randomized trials consistently show benefits of exercise for weight loss, but the effects are often modest. This may result from small sample sizes, short study duration, and poor adherence to the exercise prescriptions. To better define the doses and types of exercise that will promote long-term weight loss, it is necessary to develop better ways to measure exercise and promote adherence to exercise.

Adult↗
PubMed1999

Skeletal muscle fatty acid metabolism in association with insulin resistance, obesity, and weight loss.

The current study was undertaken to investigate fatty acid metabolism by skeletal muscle to examine potential mechanisms that could lead to increased muscle triglyceride in obesity. Sixteen lean and 40 obese research volunteers had leg balance measurement of glucose and free fatty acid (FFA) uptake (fractional extraction of [9,10 (3)H]oleate) and indirect calorimetry across the leg to determine substrate oxidation during fasting and insulin-stimulated conditions. Muscle obtained by percutaneous biopsy had lower carnitine palmitoyl transferase (CPT) activity and oxidative enzyme activity in obesity (P < 0.05). During fasting conditions, obese subjects had an elevated leg respiratory quotient (RQ, 0.83 +/- 0.02 vs. 0.90 +/- 0.01; P < 0.01) and reduced fat oxidation but similar FFA uptake across the leg. During insulin infusions, fat oxidation by leg tissues was suppressed in lean but not obese subjects; rates of FFA uptake were similar. Fasting values for leg RQ correlated with insulin sensitivity (r = -0.57, P < 0.001). Thirty-two of the obese subjects were restudied after weight loss (WL, -14.0 +/- 0.9 kg); insulin sensitivity and insulin suppression of fat oxidation improved (P < 0.01), but fasting leg RQ (0.90 +/- 0.02 vs. 0.90 +/- 0.02, pre-WL vs. post-WL) and muscle CPT activity did not change. The findings suggest that triglyceride accumulation in skeletal muscle in obesity derives from reduced capacity for fat oxidation and that inflexibility in regulating fat oxidation, more than fatty acid uptake, is related to insulin resistance.

Adult↗
PubMed1999

Effects of weight loss on regional fat distribution and insulin sensitivity in obesity.

Weight loss (WL) decreases regional depots of adipose tissue and improves insulin sensitivity, two parameters that correlate before WL. To examine the potential relation of WL-induced change in regional adiposity to improvement in insulin sensitivity, 32 obese sedentary women and men completed a 4-month WL program and had repeat determinations of body composition (dual-energy X-ray absorptiometry and computed tomography) and insulin sensitivity (euglycemic insulin infusion). There were 15 lean men and women who served as control subjects. VO2max was unaltered with WL (39.2 +/- 0.8 vs. 39.8 +/- 1.1 ml x fat-free mass [FFM](-1) x min(-1)). The WL intervention achieved significant decreases in weight (100.2 +/- 2.6 to 85.5 +/- 2.1 kg), BMI (34.3 +/- 0.6 to 29.3 +/- 0.6 kg/m2), total fat mass (FM) (36.9 +/- 1.5 to 26.1 +/- 1.3 kg), percent body fat (37.7 +/- 1.3 to 31.0 +/- 1.5%), and FFM (59.2 +/- 2.3 to 55.8 +/- 2.0 kg). Abdominal subcutaneous and visceral adipose tissue (SAT and VAT) were reduced (494 +/- 19 to 357 +/- 18 cm2 and 157 +/- 12 to 96 +/- 7 cm2, respectively). Cross-sectional area of low-density muscle (LDM) at the mid-thigh decreased from 67 +/- 5 to 55 +/- 4 cm2 after WL. Insulin sensitivity improved from 5.9 +/- 0.4 to 7.3 +/- 0.5 mg x FFM(-1) x min(-1) with WL. Rates of insulin-stimulated nonoxidative glucose disposal accounted for the majority of this improvement (3.00 +/- 0.3 to 4.3 +/- 0.4 mg x FFM(-1) x min(-1)). Serum leptin, triglycerides, cholesterol, and insulin all decreased after WL (P < 0.01). After WL, insulin sensitivity continued to correlate with generalized and regional adiposity but, with the exception of the percent decrease in VAT, the magnitude of improvement in insulin sensitivity was not predicted by the various changes in body composition. These interventional weight loss data underscore the potential importance of visceral adiposity in relation to insulin resistance and otherwise suggest that above a certain threshold of weight loss, improvement in insulin sensitivity does not bear a linear relationship to the magnitude of weight loss.

Abdomen↗
PubMed1998

Lifetime weight cycling and psychological health in normal-weight and overweight women.

OBJECTIVE: The relationship between weight cycling history and psychological health was studied in a sample of 429 normal-weight and overweight women. METHOD: Participants were from the Healthy Women Study, a longitudinal investigation of biological and psychosocial aspects of menopause. Participants were asked to report retrospectively details on their weight cycling history in terms of the frequency and magnitude of previous weight loss episodes. Data were examined using the total cycle weight lost and the frequency of weight cycles > or = 10 lb. Self-reported measures of depression, stress, anxiety, and anger were used to evaluate psychological health. RESULTS: For both normal-weight and overweight women, the analyses revealed no adverse relationships between weight cycling history and the psychological measures. DISCUSSION: These findings suggest that a history of weight cycling regardless of weight status does not adversely impact psychological health.

Adaptation, Psychological↗
PubMed1998

Clinic-based vs. home-based interventions for preventing weight gain in men.

OBJECTIVE: Weight gain occurs frequently in men aged 25-40. This study compared the effectiveness of a clinic-based and a home-based intervention with a no-treatment control group in preventing this weight gain. RESEARCH METHODS AND PROCEDURES: Men (n=67)-aged 25 to 40, sedentary, with a body mass index of 22 to 30, recruited from the University of Pittsburgh-were randomly assigned to 4-month treatments focused on increasing aerobic exercise and reducing fat intake through a clinic-based (CB) or a home-based (HB) program, or to a delayed-treatment control group. Subjects were reassessed at 4 months. RESULTS: Adherence and outcome did not differ significantly between the CB and HB programs, except that CB subjects recorded their food intake more frequently, and a greater number of CB subjects achieved a total of 120 miles of exercise over the 4 months. Subjects in the two intervention conditions combined lost significantly more weight (-1.6+/-2.5 kg) than control subjects, who gained 0.2+/-1.9 kg (p<0.01); this effect of treatment was seen primarily in men with a body mass index of 27 to 30 (-2.7 kg for CB and HB combined vs. + 1.5 kg for control). Treated subjects also had somewhat greater improvements in body composition, aerobic fitness, and weekly energy expenditure than controls, although these differences did not reach significance. DISCUSSIONS: Both CB and HB intervention show promise in preventing weight gain in young men, especially in those who are slightly overweight. Larger studies, using more representative samples of young men, appear warranted.

Adult↗
PubMed1998

Persons successful at long-term weight loss and maintenance continue to consume a low-energy, low-fat diet.

OBJECTIVES: To describe the dietary intakes of persons who successfully maintained weight loss and to determine if differences exist between those who lost weight on their own vs those who received assistance with weight loss (eg, participated in a commercial or self-help program or were seen individually by a dietitian). Intakes of selected nutrients were also compared with data from the third National Health and Nutrition Examination Survey (NHANES III) and the 1989 Recommended Dietary Allowances (RDAs). SUBJECTS: Subjects were 355 women and 83 men, aged 18 years or older, primarily white, who had maintained a weight loss of at least 13.6 kg for at least 1 year, and were the initial enrollees in the ongoing National Weight Control Registry. On average, the participants had lost 30 kg and maintained the weight loss for 5.1 years. METHODS: A cross-sectional study in which subjects in the registry completed demographic and weight history questionnaires as well as the Health Habits and History Questionnaire developed by Block et al. Subjects' dietary intake data were compared with that of similarly aged men and women in the NHANES III cohort and to the RDAs. Adequacy of the diet was assessed by comparing the intake of selected nutrients (iron; calcium; and vitamins C, A, and E) in subjects who lost weight on their own or with assistance. RESULTS: Successful maintainers of weight loss reported continued consumption of a low-energy and low-fat diet. Women in the registry reported eating an average of 1,306 kcal/day (24.3% of energy from fat); men reported consuming 1,685 kcal (23.5% of energy from fat). Subjects in the registry reported consuming less energy and a lower percentage of energy from fat than NHANES III subjects did. Subjects who lost weight on their own did not differ from those who lost weight with assistance in regards to energy intake, percent of energy from fat, or intake of selected nutrients (iron; calcium; and vitamins C, A, and E). In addition, subjects who lost weight on their own and those who lost weight with assistance met the RDAs for calcium and vitamins C, A, and E for persons aged 25 years or older. APPLICATIONS: Because continued consumption of a low-fat, low-energy diet may be necessary for long-term weight control, persons who have successfully lost weight should be encouraged to maintain such a diet.

Adult↗
PubMed1998

Are smaller weight losses or more achievable weight loss goals better in the long term for obese patients?

Weight losses and psychological well-being were examined at 30 months in 69 men and 61 women initially treated with behavior therapy as a function of (a) initial weight loss and (b) weight-loss goals. Initial weight losses were positively, not negatively, related to weight loss at 30 months. Weight loss goals did not predict short-term or long-term weight loss. People who reached weight goals had better long-term weight losses than those who did not, but this finding was largely due to differences in initial weight loss. Psychological well-being at 30 months was not related to initial weight losses or goals. Although correlational rather than experimental, these results do not support the hypothesis that obese patients should be encouraged to set lower weight-loss goals.

Adult↗
PubMed1998

Use of personal trainers and financial incentives to increase exercise in a behavioral weight-loss program.

Exercise is the best predictor of long-term weight loss. This study evaluated two strategies for improving exercise adherence and long-term weight loss in obese outpatients. Obese men and women (N = 193) were randomized to 1 of 5 treatment groups for 18 months: standard behavior therapy (SBT); SBT with supervised walks (SW) 3 times per week; SBT + SW with personal trainers (PT), who walked with participants, made phone reminders, and did make-up SW; SBT + SW with monetary incentives (I) for completing SW; and SBT + SW + PT + I. Both PT and I enhanced attendance at SWs, the combination producing the best adherence. Increased walk attendance did not result in higher overall energy expenditure, however, and long-term weight loss was also not improved. Post hoc analyses suggest that the level of exercise needed for successful long-term weight loss is much higher than that usually recommended in behavioral treatment programs.

Adult↗
PubMed1998

Psychological symptoms in individuals successful at long-term maintenance of weight loss.

Set point theory suggests that successful maintenance of weight loss ("weight suppression") may be associated with psychological distress. This study examined the association between psychological symptoms and body weight suppression by using a registry of 629 women and 155 men who lost at least 13.6 kg (mean loss = 30 +/- 15 kg) and maintained the loss for at least 1 year (mean duration = 5.5 +/- 6.8 years). Participants completed measures of mood, distress, restraint, disinhibition, bingeing, and purging. Maintainers' levels of distress and depression were lower than those of psychiatric samples and resembled those of community-based samples. Binge-eating and purging rates were comparable to rates of community samples. Maintainers' levels of restraint and disinhibition were markedly different from those of eating-disordered samples, resembling levels found in patients recently treated for obesity. There was no evidence that long-term suppression of body weight is associated with psychological distress.

Adaptation, Psychological↗
PubMed1998

Differences in resting energy expenditure in African-American vs Caucasian overweight females.

OBJECTIVE: The purpose of this study was to examine differences in both resting energy expenditure (REE) and respiratory quotient (RQ) between overweight African-American and Caucasian women of comparable age and body mass index (BMI). DESIGN: Cross-sectional. SUBJECTS: REE was assessed in 41 women (22 African-American and 19 Caucasian) who were recruited to participate in this study. The African-American women were aged 36.4+/-5.7 y with a BMI of 32.6+/-5.4 kg/m2, and the Caucasian women were aged 35.4+/-5.7 y with a BMI of 31.3+/-3.4 kg/m2. MEASUREMENTS: Body composition was assessed using dual energy x-ray absorptiometry (DEXA). REE was assessed via the dilution technique following an overnight fast. RESULTS: REE was lower in African-Americans (7279+/-825 kJ/d) compared to Caucasians (7807+/-854 kJ/d) (P = 0.051). Analysis of covariance showed that REE remained significantly lower in African-American women after correcting for body weight and lean body mass. There was no effect of ethnicity on RQ. CONCLUSION: These results indicate that there is a significant difference in REE between Caucasian and African-American overweight women. This difference in REE may contribute to the higher rates of obesity found in the African-American population. This difference may also partially explain the smaller weight losses typically seen in African-American women when compared to Caucasian women enrolled in a weight loss program.

Adult↗
PubMed1998

Bioelectrical impedance analysis to assess body composition in obese adult women: the effect of ethnicity.

OBJECTIVE: To examine whether the accuracy of bioelectrical impedance analysis (BIA) to estimate body composition in overweight women is affected by the ethnicity of the individuals. DESIGN: Cross-sectional design to compare body composition estimated by BIA to body composition measured by dual energy x-ray absorptiometry (DEXA), which was the reference method. SUBJECTS: One hundred twenty three overweight women participated in this study, of which 43 women were African-American (aged 37.2+/-5.6 y; BMI, 32.3+/-4.9 kg/m2) and 80 were Caucasian (aged 36.1+/-5.7 y; BMI, 31.9+/-3.5 kg/m2). MEASUREMENTS: Body composition was estimated from BIA using both a generalized and an obesity-specific equation. These estimations were compared to body composition measured by DEXA, which was the reference method. RESULTS: The generalized BIA equation underestimated lean body mass (LBM) by 2.6+/-3.1 kg in Caucasian women and 0.4+/-3.2 kg in African-American women, with the difference between the ethnic groups being significant (P < 0.001). The obesity-specific equation underestimated LBM in Caucasians by 0.9+/-3.1 kg and overestimated LBM in African-Americans by 1.2+/-2.8 kg (P < 0.001). An ethnic-specific equation is proposed, and cross-validation of this equation indicates that it provides a reasonable estimate of body composition in overweight women. CONCLUSIONS: The accuracy of BIA to estimate body composition appears to be affected by the ethnicity of the individual. Therefore, an ethnic-specific equation for overweight women is proposed. However, further validation of this prediction model in an ethnically diverse population is necessary.

Absorptiometry, Photon↗
PubMed1998

Long-term maintenance of weight loss: do people who lose weight through various weight loss methods use different behaviors to maintain their weight?

OBJECTIVE: To evaluate whether individuals who lost weight on their own (n = 447), through organized programs (n = 313) or with liquid formula (n = 133) would differ in the strategies they used to maintain their weight losses. DESIGN: All subjects were members of the National Weight Control Registry, had lost > or = 13.6 kg (30 pounds), and kept it off at least one year (mean weight loss = 30.1+/-14.9 kg and mean duration of maintenance = 5.7+/-6.9 y). RESULTS: Liquid Formula users differed from the other two groups on many characteristics; they were more likely to be women, older, heavier, and to have had a medical disorder prior to weight loss. To maintain their weight loss, the Liquid Formula group reported greater use of dietary strategies (for example, counting calories, limiting the amount of calories from fat) and higher dietary restraint. Liquid Formula users reported that weight maintenance was more difficult than losing weight, whereas individuals who lost weight on their own reported the reverse. The On Own group reported expending a higher percentage of calories through strenuous activities such as running and weight lifting, and reported weighing themselves more frequently to maintain weight loss. Despite these behavioral differences, all three groups are maintaining their weight losses similarly by eating a low calorie diet (5792.3 kJ/d and 25% of daily calories from fat) and engaging in high levels of physical activity (11847.3 kJ/week). CONCLUSIONS: Despite using different methods to lose weight, individuals who lost weight on their own, through an organized program, or with a liquid formula, use similar behavioral strategies to maintain their weight loss.

Adolescent↗
PubMed1998

Reducing postpartum weight retention through a correspondence intervention.

OBJECTIVE: Since post-pregnancy weight retention may contribute to the development of obesity, we sought to determine whether a behavioral weight loss intervention was effective in returning women to their pre-pregnancy weight. METHOD: Ninety women who had given birth in the past 3-12 months and whose weight exceeded their pre-pregnancy weight by at least 6.8 kg were randomly assigned to either: a) a six-month behavioral weight loss intervention, delivered via correspondence or b) a no-treatment control group. Assessments of body weight, physical activity and eating patterns were conducted at pre-treatment and six months (post-treatment). RESULTS: During the six month treatment, subjects in the correspondence condition lost significantly more weight than control subjects (7.8 kg vs 4.9 kg, P = 0.03) and lost a greater percentage of their excess postpartum weight (79% vs 44%, P = 0.01). Furthermore, a significantly greater percentage of correspondence subjects than controls returned to their pre-pregnancy weight (33% vs 11.5%, P < 0.05). Weight loss in the correspondence group was correlated with completion of self-monitoring records (r = 0.50, P < 0.005). CONCLUSIONS: A behavioral weight loss intervention, delivered via correspondence, appears to be effective in reducing women's postpartum weight retention. Future studies should examine the acceptability and the long-term impact of a correspondence postpartum weight loss intervention.

Adolescent↗
PubMed1998

Accuracy of self-reported exercise and the relationship with weight loss in overweight women.

PURPOSE: The purpose of this study was to compare self-reported exercise to a more objective measurement of exercise (i.e., Tri-Trac Accelerometer) and to assess whether there is a difference in weight loss between individuals who under- and over-report their exercise. METHODS: Fifty overweight females (BMI = 34.0 +/- 4.2 kg.m-2) who were participating in a behavioral weight control program were included in this study. Subjects were randomly assigned to a long-bout or a short-bout exercise condition, with both groups instructed to exercise 30 min.day-1 on 5 d.wk-1 for a period of 20 wk. The long-bout group was to exercise in one continuous session (e.g., one 30-min session per day), whereas the short-bout group was to divide the exercise into multiple 10-min sessions (e.g., three 10-min sessions per day). Subjects recorded their exercise in a daily exercise log and wore a Tri-Trac accelerometer for a 1-wk period to validate self-reported exercise bouts. RESULTS: Results showed that approximately 45% of the women over-reported the amount of exercise that they performed, and this did not differ between the long-bout and short-bout groups. Women who over-reported their exercise had significantly poorer weight loss across the 20-wk program than women who under-reported their exercise (6.3 +/- 3.6 kg vs 9.4 +/- 5.2 kg). CONCLUSIONS: The results of this study suggest that overweight women who over-report their exercise will have poorer weight loss while enrolled in a behavioral weight loss program compared with others enrolled in the program, and the Tri-Trac Accelerometer may be useful in identifying individuals who inaccurately report the amount of their exercise. The ability to classify individuals as either over- or under-reporters of their exercise may be helpful to weight loss therapists and lead to more successful treatment for obesity.

Adult↗
PubMed1998

Smoking cessation, weight gain, and changes in cardiovascular risk factors during menopause: the Healthy Women Study.

OBJECTIVES: The relationship between smoking cessation, subsequent weight gain, and cardiovascular disease risk factors from premenopause to postmenopause was studied. METHODS: Healthy Women Study participants were assessed for changes in coronary heart disease risk factors from a premenopausal baseline assessment to first- and second-year postmenopausal assessments. RESULTS: Although ex-smokers gained substantially more weight than nonsmokers and smokers, they did not experience a greater increase in cardiovascular risk factors. In fact, the results indicated a trend toward ex-smokers' high-density lipoprotein cholesterol levels increasing slightly more than those of nonsmokers and smokers. CONCLUSIONS: Smoking cessation in perimenopausal to postmenopausal women is associated with greater weight gain but appears to be modestly associated with certain positive changes in cardiovascular risk factors.

Alcohol Drinking↗
PubMed1998

The effect of short periods of caloric restriction on weight loss and glycemic control in type 2 diabetes.

OBJECTIVE: To determine whether an intermittent very-low-calorie diet (VLCD) improves weight loss and glycemic control more than moderate caloric restriction alone. RESEARCH DESIGN AND METHODS: Individuals with type 2 diabetes (n = 54) who were > or = 20% over ideal body weight participated in a 20-week behavioral weight control program. Subjects were randomized to either a standard behavioral therapy (SBT) group or to one of two VLCD groups. SBT subjects received a 1,500-1,800 kcal/day diet throughout. Both VLCD groups followed a VLCD for 5 consecutive days during week 2, followed by either intermittent VLCD therapy for 1 day/week for 15 weeks (1-day) or for 5 consecutive days every 5 weeks (5-day), with a 1,500-1,800 kcal/day diet at other times. RESULTS: Both VLCD groups lost more weight than the SBT group over the 20 weeks (P = 0.04). Although the groups did not differ in fasting plasma glucose (FPG) changes at 20 weeks, more subjects in the 5-day group attained a normal HbA1c when compared with the SBT group (P = 0.04). This benefit was independent of the effects of weight loss. The best predictor of overall change in FPG and HbA1c was the FPG response during the first 3 weeks of the program. CONCLUSIONS: Periodic VLCDs improved weight loss in diabetic subjects. A regimen with intermittent 5-day VLCD therapy seemed particularly promising, because more subjects in this group attained a normal HbA1c. Moreover, the glucose response to a 3-week period of diet therapy predicted glycemic response at 20 weeks, and it was a better predictor of the 20-week response than initial or overall weight loss.

Adult↗
PubMed1998

Lifestyle intervention in overweight individuals with a family history of diabetes.

OBJECTIVE: To assess the effect of lifestyle intervention over 2 years on changes in weight, coronary heart disease (CHD) risk factors, and incidence of diabetes in overweight individuals with a parental history of diabetes. RESEARCH DESIGN AND METHODS: Participants (n = 154), who were 30-100% over ideal body weight, had one or both parents with diabetes, and were currently nondiabetic, were randomly assigned to 2-year treatments focused on diet (decreasing calories and fat intake), exercise (goal of 1,500 kcal/week of moderate activity), or the combination of diet plus exercise or to a no-treatment control group. Subjects were reassessed at 6 months, 1 year, and 2 years. RESULTS: At 6 months, the groups differed significantly on measures of eating, exercise, and fitness; weight losses in the diet and diet-plus-exercise groups were significantly greater than in the exercise and control conditions. Weight losses were associated with positive changes in CHD risk factors. After 6 months, there was gradual deterioration of behavioral and physiological changes, so that at 2 years, almost no between-group differences were maintained. Differences between groups in risk of developing diabetes were of borderline significance (P = 0.08). Strongest predictors were impaired glucose tolerance at baseline, which was positively related to risk of developing diabetes, and weight loss from baseline to 2 years, which was negatively related; in all treatment groups, a modest weight loss of 4.5 kg reduced the risk of type 2 diabetes by approximately 30% compared with no weight loss. CONCLUSIONS: Although initially successful, the interventions studied here were not effective in producing long-term changes in behavior, weight, or physiological parameters. However, weight loss from 0 to 2 years reduced the risk of developing type 2 diabetes. Since modest weight loss significantly reduced risk of type 2 diabetes, further research is needed to determine how best to increase the percentage of subjects achieving at least a modest weight loss.

Adult↗