Biomedical subjects

M T McGuire

Publications and source records attributed to M T McGuire.

At least 19 recordsLinked to original sources

PubMed2002

Prevalence and correlates of large weight gains and losses.

OBJECTIVE: To examine the prevalence and correlates of large weight gains and losses over a 3 y period in a heterogeneous population of participants in a study of weight gain prevention. DESIGN AND MEASURES: Analyses based on a cohort of 823 participants in a weight gain prevention study whose weight was measured on at least two of four annual examinations. RESULTS: Weight gains and losses of >or=5% body weight over 1 y were observed in 9.3 and 15% of the population, respectively. Weight gains among those initially losing weight were significantly greater (3.9 kg) than among those experiencing stable weight (0.8 kg) or a large weight gain (1.5 kg) over the following 2 y. Cumulative weight changes over 3 y were -2.6, 1.0 and 7.6 kg among large loss, weight stable and large gain groups, respectively. Large weight loss was more common in smokers, large gains were more common in younger people and in those with a more extensive weight loss history, and stable weight was observed more often in individuals with less extensive histories of weight loss. CONCLUSION: The high prevalence of large short-term weight gains and losses in this heterogeneous population, their apparent resistance to short-term reversal, and the strength of their relationship to longer-term weight trends suggest that rapid weight change over relatively short time intervals is a phenomenon that deserves more research attention. Short periods of rapid weight gain may contribute importantly to rapidly rising obesity rates.

Adult↗

PubMed2002

Weight-related attitudes and behaviors of adolescent boys and girls who are encouraged to diet by their mothers.

OBJECTIVE: To assess the relationships between mothers' reports of dieting and encouraging adolescents to diet and adolescents' reports of their own dieting practices and weight-related concerns. DESIGN: Cross-sectional study of parent interviews and adolescent surveys in an ethnically-diverse sample. SUBJECTS: A total of 810 adolescents (n=381 boys and n=429 girls) and their mothers. RESULTS: Mothers' dieting was associated with their adolescent girls' weight-related concerns and behaviors, but these associations were not significant after adjusting for girls' body mass index (BMI). In contrast, mothers' encouragement for sons to diet was associated with sons' binge eating, dieting and other weight-control behaviors, even after controlling for sons' BMI. Compared with mothers who did not encourage their child to diet, mothers who encouraged their child to diet were significantly heavier women and were more likely to view their child as overweight. Forty-three percent of boys and 46% of girls who were encouraged by their mothers to diet were classified as nonoverweight by federal guidelines. CONCLUSIONS: Boys who are encouraged by their mothers to diet may be at risk for health-compromising eating and dieting behaviors, particularly binge-eating, fasting, eating a little bit of food and skipping meals. Parents who are concerned about their children's weight should be educated to encourage healthy eating habits and physical activity to promote their children's health, including healthy weight control.

Adolescent↗

PubMed2001

Social impulsivity inversely associated with CSF 5-HIAA and fluoxetine exposure in vervet monkeys.

Animal and human research suggests that the central serotonin system is involved in the inhibition of impulsive behavior. Two studies were designed to assess this relationship in male vervet monkeys (Cercopithecus aethiops sabaeus) using a standardized test of impulsivity in a social context: the Intruder Challenge. In the first study, an index of impulsivity in response to an unfamiliar adult male intruder (including latency to approach and aggressive and assertive interactions) was inversely correlated with levels of the serotonin metabolite, 5-hydroxyindoleacetic acid (5-HIAA) in cisternal cerebrospinal fluid (r = -0.33, p <.01, n = 138). The approach, but not aggressive, component of the Impulsivity Index was the primary contributor to this relationship (partial r = -0.27, p <.01). The second experiment compared responses to the Intruder Challenge after 9 weeks of daily treatment with fluoxetine (2 mg/kg, i.m.) or vehicle. Fluoxetine-treated subjects (n = 6) had significantly lower Impulsivity Index scores than controls (n = 12). The results from these two investigations provide evidence for serotonergic influences on social impulsivity.

Age Factors↗

PubMed2001

The relationship between restraint and weight and weight-related behaviors among individuals in a community weight gain prevention trial.

PURPOSE: The present study evaluated the cross-section and prospective associations between the Eating Inventory's (EI) total, flexible and rigid dietary restraint scales and changes in weight and behaviors in a community sample of adults enrolled in a 3 y weight gain prevention study. METHODS: Subjects were participants in the Pound of Prevention (POP) study, a community-based weight gain prevention trial. RESULTS: Higher levels of baseline total, flexible and rigid dietary restraint were related to lower weight and more weight-controlling behaviors at the baseline assessment. Baseline restraint measures positively predicted increases in weighing frequency over the 3 y follow-up. Increases in restraint over the follow-up period were related to decreases in weight, energy intake and television watching, and increases in self-weighing and physical activity. CONCLUSION: The EI's total, flexible and rigid restraint scales were not differently associated with weight and behaviors in this heterogeneous sample of adults who were attempting to lose weight. Developing methods to increase behavioral and cognitive strategies to control weight may help to prevent weight gain in clinical and community samples.

Adult↗

PubMed2001

Interventions for weight loss and weight gain prevention among youth: current issues.

The recent increase in the prevalence of paediatric obesity is one of the most pressing public health concerns today because of the immediate and long term health consequences associated with this often intractable disease. Efforts are currently being made to reduce the prevalence of paediatric obesity. Youth weight loss studies have produced significant long term results. Most of these programmes included behaviour modification, diet and exercise. Studies have suggested that lifestyle exercise programmes may produce the best long term results. Effective components of these programmes appear to be parental involvement, reduced intake of foods having high energy density and reductions in physical inactivity. Future weight loss studies need to determine the type, intensity, and duration of exercise that will produce acceptable adherence and consequent long term weight loss, and to ascertain the reinforcing factors that determine youth behaviour choice. Weight gain prevention interventions for youth are clearly in their infancy. This review describes 3 completed and 2 ongoing weight gain prevention trials. One study showed reductions in the prevalence of obesity among junior high school girls, but not among boys. Another study among elementary school students showed significant mean decreases in body mass index in boys and girls following an intervention specifically to reduce time spent viewing television. Whether these studies altered food intake or increased physical activity remains unclear. A combination of weight loss treatment and weight gain prevention strategies employed in parallel is likely to yield the greatest benefits. Development and testing of novel intervention strategies, using innovative behavioural approaches to increase the likelihood that children will adopt healthy dietary, physical activity, and sedentary behaviour patterns, holds great promise to significantly reduce the epidemic of obesity.

Adolescent↗

PubMed2000

Does weight loss maintenance become easier over time?

OBJECTIVE: Studies of health-related behaviors, including weight loss, have shown that risk of relapse decreases over time, although reasons for this relationship are unclear. The purpose of this cross-sectional study was to determine if subjects who have maintained weight losses for varying periods of time report different strategies for weight loss maintenance or differences in the effort and pleasure associated with weight maintenance behaviors. RESEARCH METHODS AND PROCEDURES: Subjects were 758 women and 173 men who had maintained losses of at least 30 lb (mean = 60 lb) for 2 years or longer (mean = 6.8 +/- 7.0 years). Self-administered questionnaires assessed subjects' use of weight maintenance strategies in the past year and their perceptions of the effort, attention, and pleasure associated with weight maintenance. RESULTS: Subjects who had maintained weight losses longer used fewer weight maintenance strategies and reported that less effort was required to diet and maintain weight and that less attention was required to maintain weight. The pleasure derived from exercise, low-fat eating, and maintaining weight was unrelated to duration of weight loss maintenance. DISCUSSION: As duration increases, a shift in the balance between the effort and pleasure of weight maintenance may occur. This shift may increase the likelihood of continued maintenance.

Adult↗

PubMed2000

A case-control study of successful maintenance of a substantial weight loss: individuals who lost weight through surgery versus those who lost weight through non-surgical means.

OBJECTIVE: To determine if method of weight loss (surgery; non-surgery) is associated with current levels of psychosocial functioning or current weight maintenance behaviors in individuals who have lost large amounts of weight. DESIGN: Subjects were 67 cases and 67 controls selected from the National Weight Control Registry, a longitudinal study of individuals successful at long-term maintenance of weight loss. Cases had initially lost weight through bariatric surgery while controls had lost weight through non-surgical means. The current psychosocial functioning and weight maintenance behaviors of cases and controls were assessed and compared. RESULTS: Cases and controls were matched on gender, current weight and total weight loss. Surgical cases reported significantly higher fat intake and lower physical activity levels. There were no differences in cases' and controls' reports of the impact of weight loss on other areas of their lives, neither were there differences on measures of depression or binge-eating. CONCLUSIONS: Reported improvement in psychosocial functioning did not depend upon how weight was initially lost, but cases and controls appear to be using very different behaviors to maintain their weight losses.

Adult↗

PubMed1999

Behavioral strategies of individuals who have maintained long-term weight losses.

OBJECTIVE: The purpose of the present study was to compare the behaviors of individuals who have achieved long-term weight loss maintenance with those of regainers and weight-stable controls. RESEARCH METHODS AND PROCEDURES: Subjects for the present study were participants in a random-digit dial telephone survey that used a representative sample of the U.S. adult population. Eating, exercise, self-weighing, and dietary restraint characteristics were compared among weight-loss maintainers: individuals who had intentionally lost > or =10% of their weight and maintained it for > or = 1 year (n = 69), weight-loss regainers: individuals who intentionally lost > or = 10% of their weight but had not maintained it (n = 56), and weight-stable controls: individuals who had never lost > or = 10% of their maximum weight and had maintained their current weight (+/-10 pounds) within the past 5 years (n = 113). RESULTS: Weight-loss maintainers had lost an average of 37 pounds and maintained it for over 7 years. These individuals reported that they currently used more behavioral strategies to control dietary fat intake, have higher levels of physical activity (especially strenuous activity), and greater frequency of self-weighing than either the weight-loss regainers or weight-stable controls. Maintainers and regainers did not differ in reported levels of dietary restraint, but both had higher levels of restraint than the weight-stable controls. DISCUSSION: These results suggest that weight-loss maintainers use more behavioral strategies to control their weight than either regainers or weight-stable controls. It would thus appear that long-term weight maintenance requires ongoing adherence to a low-fat diet and an exercise regimen in addition to continued attention to body weight.

Adult↗

PubMed1999

The behavioral characteristics of individuals who lose weight unintentionally.

OBJECTIVE: To determine whether individuals who unintentionally lost weight differ from individuals who intentionally lost weight in behavioral characteristics related to chronic disease risk factors. DESIGN: A random-digit dial telephone survey was conducted among a representative sample of American adults (n = 500). SUBJECTS: Of the 500 individuals sampled, 139 were currently > or = 10% below their lifetime maximum weight. These individuals were asked whether their weight loss was unintentional or intentional. Unintentional (n =49) and intentional (n = 89) weight losers were compared on measures of dietary intake, physical activity, smoking, drinking, and self-reported health status. RESULTS: Unintentional weight losers had higher levels of smoking and drinking, were less physically active, and were less concerned about their diet and fat intake. Unintentional weight losers did not report having higher levels of disease such as high blood pressure or diabetes. However, unintentional weight losers who reported having such diseases were more likely to report that their weight loss had no effect or had worsened their disorder. DISCUSSION: Compared to intentional weight losers, those who lost their weight unintentionally reported engaging in more negative health behaviors that are related to disease morbidity and mortality. These data suggest that unintentional weight loss may be part of a cluster of behaviors that have a negative health impact.

Adult↗

PubMed1999

What predicts weight regain in a group of successful weight losers? .

This study identified predictors of weight gain versus continued maintenance among individuals already successful at long-term weight loss. Weight, behavior, and psychological information was collected on entry into the study and 1 year later. Thirty-five percent gained weight over the year of follow-up, and 59% maintained their weight losses. Risk factors for weight regain included more recent weight losses (less than 2 years vs. 2 years or more), larger weight losses (greater than 30% of maximum weight vs. less than 30%), and higher levels of depression, dietary disinhibition, and binge eating levels at entry into the registry. Over the year of follow-up, gainers reported greater decreases in energy expenditure and greater increases in percentage of calories from fat. Gainers also reported greater decreases in restraint and increases in hunger, dietary disinhibition, and binge eating. This study suggests that several years of successful weight maintenance increase the probability of future weight maintenance and that weight regain is due at least in part to failure to maintain behavior changes.

Adult↗

PubMed1999

The prevalence of weight loss maintenance among American adults.

BACKGROUND: Previous studies suggest that few individuals achieve long-term weight loss maintenance. Because most of these studies were based on clinical samples and focused on only one episode of weight loss, these results may not reflect the actual prevalence of weight loss maintenance in the general population. DESIGN: A random digit dial telephone survey was conducted to determine the point prevalence of weight loss maintenance in a nationally representative sample of adults in the United States. Weight loss maintainers were defined as individuals who, at the time of the survey, had maintained a weight loss of > or =10% from their maximum weight for at least 1 y. The prevalence of weight loss maintenance was first determined for the total group (n = 500), and then for the subgroup of individuals who were overweight (body mass index BMI > or =27 kg/m2 at their maximum (n = 228). RESULTS: Weight loss was quite common in this sample: 54% of the total sample and 62% of those who were ever overweight reported that they had lost > or =10% of their maximum weight at least once in their lifetime, with approximately one-half to two-thirds of these cases being intentional weight loss. Among those who had achieved an intentional weight loss of > or =10%, 47-49% had maintained this weight loss for at least 1 y at the time of the survey; 25-27% had maintained it for 5 y or more. Fourteen percent of all subjects surveyed and 21% of those with a history of obesity were currently 10% below their highest weight, had reduced intentionally, and had maintained this 10% weight loss for at least 1 y. CONCLUSIONS: A large proportion of the American population has lost > or =10% of their maximum weight and has maintained this weight loss for at least 1 y. These findings are in sharp contrast to the belief that few people succeed in long-term weight loss maintenance.

Adult↗

PubMed1999

Resting energy expenditure in reduced-obese subjects in the National Weight Control Registry.

BACKGROUND: Weight loss in obese subjects is associated with a reduction in resting metabolic rate (RMR). Whether the reduction can be explained solely by a reduction in lean body mass remains controversial. OBJECTIVE: Our objective was to determine whether the reduction in RMR after weight loss was proportional to the decrease in lean mass alone or was greater than could be explained by body composition. DESIGN: We measured the RMR, fasting respiratory quotient (RQ), and body composition in 40 reduced-obese subjects [ie, 7 men and 33 women who had lost > or = 13.6 kg (30 lb) and maintained the loss for > or = 1 y] enrolled in the National Weight Control Registry and 46 weight-matched control subjects (9 men, 37 women). RESULTS: A stepwise multiple regression found lean mass, fat mass, age, and sex to be the best predictors of RMR in both groups. After adjusting RMR for these variables, we found no significant difference in RMR (5926 +/- 106 and 6015 +/- 104 kJ/d) between the 2 groups (P = 0.35). When we adjusted fasting RQ for percentage body fat and age, the reduced-obese group had a slightly higher (0.807 +/- 0.006) RQ than the control group (0.791 +/- 0.005, P = 0.05). This may have been due to the consumption of a diet lower in fat or to a reduced capacity for fat oxidation in the reduced-obese group. CONCLUSION: These results show that in at least some reduced-obese individuals there does not seem to be a permanent obligatory reduction in RMR beyond the expected reduction for a reduced lean mass.

Basal Metabolism↗

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

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

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

Prevalence differences in depression among males and females: are there evolutionary explanations?

Differences in male-female prevalence rates of depression are interpreted in evolutionary perspective. Three evolutionary hypotheses are evaluated: (a) depression represents an evolved strategy to deal with adverse social interactions, particularly among partners, (b) depression has self-preservative and manipulative features, and (c) depression is a consequence of failing to achieve biological goals. While these hypotheses are not necessarily mutually exclusive, evolutionary explanations often suffer from not specifying which hypothesis is primary and which are secondary. We argue that failing to achieve biological goals is primary and that evolved strategies and self-preservative and manipulative behaviour are secondary. Findings pointing to depression-contributing features of male-female differences, asymmetries in male-female relationships and male-female differences associated with reproduction are discussed to support our view that evolutionary explanations can adequately account for a significant percentage of the reported prevalence differences.

Adaptation, Psychological↗

PubMed1997

A descriptive study of individuals successful at long-term maintenance of substantial weight loss.

The National Weight Control Registry (NWCR) is, to the best of our knowledge, the largest study of individuals successful at long-term maintenance of weight loss. Despite extensive histories of overweight, the 629 women and 155 men in the registry lost an average of 30 kg and maintained a required minimum weight loss of 13.6 kg for 5 y. A little over one-half of the sample lost weight through formal programs; the remainder lost weight on their own. Both groups reported having used both diet and exercise to lose weight and nearly 77% of the sample reported that a triggering event had preceded their successful weight loss. Mean (+/-SD) current consumption reported by registry members was 5778 +/- 2200 kJ/d, with 24 +/- 9% of energy from fat, Members also appear to be highly active: they reported expending approximately 11830 kJ/wk through physical activity. Surprisingly, 42% of the sample reported that maintaining their weight loss was less difficult than losing weight. Nearly all registry members indicated that weight loss led to improvements in their level of energy, physical mobility, general mood, self-confidence, and physical health. In summary, the NWCR identified a large sample of individuals who were highly successful at maintaining weight loss. Future prospective studies will determine variables that predict continued maintenance of weight loss.

Adult↗

PubMed1995

Menstrual cycle and social behavior in vervet monkeys.

We assessed the relationship between social behavior and the menstrual cycle in 11 adult female vervet monkeys (Cercopithecus aethiops sabaeus) living in an established, stable social group. The findings indicated that fluctuations in ovarian steroids are accompanied by behavioral changes in vervet monkeys. A significant increase in aggressive action, avoidance of social overtures, and retreats from threat occurred during the late luteal phase. However, the social environment can greatly affect behavior independent of the phase of the menstrual cycle. The 10 nondominant (or subordinate) individuals not only exhibited behavioral changes across their own menstrual cycles, but also were responsive to the dominant female's cycle. During the dominant female's late luteal phase, subordinate females significantly increased aggression and decreased social activity. Some of behavioral patterns in female vervet monkeys are therefore relatively independent of direct hormonal modulation and support the contention of the dominant female as the driving force for behavioral changes related to aggression and social interaction. The differential effect of hormones and social status and other environmental factors on behavior has not been critically evaluated in human studies of the premenstrual syndrome. The present study suggests that it is important to assess which behavioral patterns in women are hormonally mediated and which are dependent on the environment.

Aggression↗