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PubMed1996

Exercise and weight control in sedentary overweight men: effects on clinic and ambulatory blood pressure.

OBJECTIVE: To examine whether restriction of caloric intake and exercise of vigorous intensity can independently and additively influence clinic and ambulatory blood pressures in sedentary overweight men. DESIGN: Sixty subjects aged 20-50 years were randomly allocated either to continue their normal caloric intake or to restrict it by 4186-6279 kl/day, with 15% provided by protein, 30% by fat and 55% by carbohydrate, for 16 weeks. Within each of these groups subjects were further randomly allocated either to a control light intensity programme of exercise or to a vigorous intensity programme of exercise for 30 min three times a week. The light exercise group performed stationary cycling against no resistance, flexibility exercises and slow walking. The vigorous intensity group cycled on an ergometer at 60-70% of maximum their workload. RESULTS: Fifty-one subjects completed the study. Their maximal oxygen uptake was increased by approximately 24% with vigorous exercise but did not change with light exercise. Caloric intake restriction led to a significant loss of body mass of 9.5 kg (95% confidence interval 7.6-11.3), whereas vigorous exercise had no effect. Restriction of caloric intake reduced supine clinic systolic and diastolic blood pressures significantly by 5.6 (2.3-8.9) and 2.4 mmHg (0.4-4.2), respectively. Relative to the control light exercise group, exercise of vigorous intensity exercise had no significant effect on clinic blood pressure. In contrast, time series analysis revealed that both caloric intake restriction and vigorous exercise were associated with lower daytime ambulatory systolic blood pressure, the reduction in systolic blood pressure being sustained throughout the 24 h period when vigorous exercise and caloric intake restriction were combined. CONCLUSION: Compared with the effects of caloric intake restriction, the effects of a vigorous exercise programme on blood pressure are inconsistent, there being no influence on clinic blood pressure but a reduction in daytime ambulatory blood pressure. However, when combined with caloric intake restriction, regular vigorous exercise exhibits a synergistic effect in reducing ambulatory blood pressure throughout a 24 h period.

Adult↗
PubMed1999

Mitochondrial uncoupling: role of uncoupling protein anion carriers and relationship to thermogenesis and weight control "the benefits of losing control".

Uncoupling proteins, a subgroup of the mitochondrial anion transporter superfamily, have been identified in prokaryotes, plants, and mammalian cells. Evolutionary conservation of these molecules reflects their importance as regulators of two critical mitochondrial functions, i.e., ATP synthesis and the production of reactive oxygen species (ROS). Although the amino acid sequences of the three mammalian uncoupling proteins, UCP1, UCP2 and UCP3, are very similar, each homolog is the product of a unique gene and important differences have been demonstrated in their tissue-specific expression and regulation. UCP1 and UCP3 appear to be key regulators of energy expenditure, and hence, nonshivering thermogenesis, either in brown adipose tissue (UCP1) or skeletal muscle (UCP3). UCP2 is expressed more ubiquitously, although generally at low levels, in many tissues. There is conflicting evidence about its importance as a regulator of resting metabolic rate. However, evidence suggests that this homolog might modulate the mitochondrial generation of ROS in some cell types, including macrophages and hepatocytes. While the induction of various uncoupling protein homologs provides adaptive advantages, both to the organism (e.g., thermogenesis) and to individual cells (e.g., reduced ROS), increased uncoupling protein activity also increases cellular vulnerability to necrosis by compromising the mitochondrial membrane potential. This narrow "risk-benefit" margin necessitates tight control of uncoupling protein activity in order to preserve cellular viability and much remains to be learned about the regulatory mechanisms involved.

Animals↗
PubMed2004

Carbohydrate and weight control: where do we stand?

PURPOSE OF THE REVIEW: The Atkins diet has been criticized and vilified by much of the scientific community since it was proposed 30 years ago, because it challenged nutritional recommendations and dietary guidelines for a healthy diet. However, in spite of such recommendations the prevalence of obesity continues to rise. The present review evaluates recent scientific evidence and attempts to reach consensus on the confusion of weight-reducing diets. RECENT FINDINGS: Many dietary macronutrient paradigms have been proposed for the treatment of obesity. Since obesity in its dynamic phase is the result of energy intake exceeding energy expenditure, intuitively to lose weight energy intake should be less than energy expenditure, and one might expect that the macronutrient composition of the diet would have very little, if any, effect. However, short- and long-term therapies with low-carbohydrate or high-protein diets appear to offer advantages over conventional weight-loss regimens for weight loss, body composition and cardiovascular risk factors. SUMMARY: Low-carbohydrate, Atkins-type diets have been demonstrated to have positive effects on weight loss and biomarkers of cardiovascular risk, which has prompted some researchers to question the validity of present-day dietary guidelines. Although evidence is accumulating in their favour, the safety and efficacy of low-carbohydrate, high-protein diets needs further long-term verification.

Body Composition↗
PubMed1984

Thermogenesis and weight control.

Compound LY104119, [R-(R*,S*)]-4-[3-[(2-hydroxy-2-phenylethyl)amino]butyl]benzamide monohydrochloride, was found to be a potent beta-agonist in the mouse. Its Ki for displacing the binding of (-)-3H-dihydroalprenolol to beta-receptors on the lung membranes from either viable yellow obese mice (VY/WfL-Avy/a) or their corresponding normal controls (VY/WfL-a/a) was 3 X 10(-7) M, comparable to that of isoproterenol which was 2 X 10(-7) M. LY104119 increased the concentration of cyclic AMP in adipose tissue, stimulated lipolysis in vitro and in vivo and the expiration of CO2 in vivo. When given s.c. or p.o., LY104119 reduced the body weight of Avy/a mice without altering the food consumption. The loss of triacylglycerol accounted for a major portion of the weight loss and the weight was recovered after the treatment was withdrawn. When fed in the diet, LY104119 reduced the weight of Avy/a mice and caused a moderate increase of food intake. Thermogenesis (whole body heat production) of the treated mice increased. An elevated level of hepatic glucokinase activity regularly found in these mice was almost normalized to the level measured in normal mice. The kinetic properties of the beta-receptors were not altered, but the number of beta-receptors on lung membranes was reduced about 25 percent. The lipolytic response of epididymal adipose tissue to LY104119 or isoproterenol, however, was not changed. When slightly overweight a/a mice were treated with LY104119 in the diet, they lost weight, but a similar treatment of normal-weight a/a mice caused a loss of only a small amount of carcass triacylglycerol without affecting the body weight. These normal-weight a/a mice were able to maintain their weight by an exorbitant increase of food intake. When this large increase of food consumption was not allowed, ie by being restricted to normal amounts of food intake, normal-weight a/a mice fed LY104119 did lose weight. Thermogenesis increased in all LY104119-treated a/a mice. However, the increase in the LY104119-treated but diet-restricted a/a mice was smaller than that in the LY104119-treated a/a mice fed ad libitum. We conclude from these observations that: Compound LY104119 was able to decrease weight in Avy/a mice apparently through the stimulation of the beta-adrenergic system. The metabolic responses to LY104119 were not different in obese Avy/a mice and normal a/a mice. The difference between the Avy/a mice and the a/a mice was in their ability to increase their food consumption to compensate for the energy loss caused by LY104119.

2-Hydroxyphenethylamine↗
PubMed1980

Double-blind evaluation of reinforcing and anorectic actions of weight control medications. Interaction of pharmacological and behavioral treatments.

Within a behavioral self-management treatment program for overweight, 59 patients were randomly assigned to receive as an adjunct either dextroamphetamine sulfate, fenfluramine hydrochloride, or placebo in a double-blind procedure. Patients self-regulated their drug intake during a four-week medication period. Two types of behavioral-pharmacological interaction were observed: (1) drug assignment influenced participation in the behavioral treatment; and (2) drug assignment influenced the extent of medication self-administration. The dextroamphetamine group was superior in terms of behavioral treatment participation, extent of eating and exercise habit change, and weight loss. Self-administration of dextroamphetamine was most well-maintained--showing it to be a reinforcer--and self-administration of fenfluramine was suppressed below placebo levels. No patient taking either drug showed excessive drug intake, and all were, in fact, conservative in drug use. These data concerning relative reinforcing efficacy within a therapeutic medication setting are discussed in relation to data from animal models used to assess relative abuse liability of these drugs.

Adult↗
PubMed2006

Coffee, diabetes, and weight control.

Several prospective epidemiologic studies over the past 4 y concluded that ingestion of caffeinated and decaffeinated coffee can reduce the risk of diabetes. This finding is at odds with the results of trials in humans showing that glucose tolerance is reduced shortly after ingestion of caffeine or caffeinated coffee and suggesting that coffee consumption could increase the risk of diabetes. This review discusses epidemiologic and laboratory studies of the effects of coffee and its constituents, with a focus on diabetes risk. Weight loss may be an explanatory factor, because one prospective epidemiologic study found that consumption of coffee was followed by lower diabetes risk but only in participants who had lost weight. A second such study found that both caffeine and coffee intakes were modestly and inversely associated with weight gain. It is possible that caffeine and other constituents of coffee, such as chlorogenic acid and quinides, are involved in causing weight loss. Caffeine and caffeinated coffee have been shown to acutely increase blood pressure and thereby to pose a health threat to persons with cardiovascular disease risk. One short-term study found that ground decaffeinated coffee did not increase blood pressure. Decaffeinated coffee, therefore, may be the type of coffee that can safely help persons decrease diabetes risk. However, the ability of decaffeinated coffee to achieve these effects is based on a limited number of studies, and the underlying biological mechanisms have yet to be elucidated.

Animals↗
PubMed1995

Nocturnal eating in binge eating disorder and matched-weight controls.

OBJECTIVE: To examine the association of nocturnal eating (getting up out of bed to eat) with overweight, binge eating, and negative mood or anxiety. METHOD: Forty overweight women diagnosed with binge eating disorder (BED) and 39 overweight controls monitored their nocturnal eating for an average of eight nights. RESULTS: Seven instances of nocturnal eating were recorded by 6 patients, all of whom were binge eaters. Foods consumed nocturnally tended to be selected from those favored for binge episodes, and reported control over nocturnal eating was low. Patients reported tiredness, but not poor mood or anxiety, at the nocturnal eating episodes. DISCUSSION: In this sample, nocturnal eating was associated more with eating disorder than overweight. This report should provide the basis of future work to determine whether nocturnal eating should be evaluated and treated among eating disordered or overweight groups of patients.

Adult↗
PubMed2005

Results of go girls: a weight control program for overweight African-American adolescent females.

OBJECTIVE: Go Girls was a church-based nutrition and physical activity program designed for overweight African-American (AA) adolescent females. RESEARCH METHODS AND PROCEDURES: Ten predominantly middle-socioeconomic churches were randomized to either a high-intensity (20 to 26 sessions) or moderate-intensity (six sessions) culturally tailored behavioral group intervention delivered over 6 months. Each session included an experiential behavioral activity, approximately 30 minutes of physical activity, and preparation and tasting of healthy foods. In the high-intensity group, girls also received four to six telephone counseling calls. From the 10 churches, 123 girls completed baseline and 6-month post-test assessments. The primary outcome was BMI; secondary outcomes included waist and hip circumferences, percentage body fat estimated by bioimpedance, serum insulin, glucose, and lipids, and cardiovascular fitness at 6-month follow-up. Selected measures were also collected at 1-year follow-up. RESULTS: At 6-month follow-up, the net difference between the high- and moderate-intensity groups was 0.5 BMI units. This difference was not statistically significant (p = 0.20). There were no significant group differences in secondary outcomes. Girls in the high-intensity condition, however, who attended more than three-quarters of the sessions had significantly lower BMI and percentage body fat relative to girls in the high-intensity group who attended fewer sessions. Findings at 1-year follow-up mirrored those at 6 months. DISCUSSION: We concluded that the intervention was not effective in reducing adiposity, although there were some positive findings among high attenders. Despite the null result, the intervention was generally well received by participants. Future interventions may require greater dose and a more structured dietary change program.

Adiposity↗
PubMed1991

Weight control after vertical banded gastroplasty for morbid obesity.

Vertical banded gastroplasty is a common method of treating morbid obesity. Several physical, behavioral, economic, and psychologic factors are believed to affect its efficacy. In this study, 100 consecutive patients received a 4.5-cm circumference band, while a second 100 consecutive patients were given a 5.0-cm circumference band. One year after surgery, with a follow-up of 97.5%, neither the patient's stoma size nor their preoperative occupation, economic status, or mental health significantly affected the patient's weight loss, which averaged 27% of their original weight. Postoperative eating behavior, however, dramatically affected weight loss. Among the patients who lost less than 20% of their original weight, 25% drank large volumes of caloried liquids, while 75% ate large amounts of soft foods. Patients with banded gastroplasties must "use" their operation to lose weight.

Adult↗
PubMed1985

Weight control in young college women: who are the dieters?

Dieting behavior was studied in 166 young college women, 18 to 24 years old. The women were divided into three groups on the basis of the amount of time they had spent dieting during the previous school year (8 months). Of the whole population, 18.1% had spent more than half the time dieting (chronic dieters), 45.2% had dieted 50% of the time or less (periodic dieters), and 36.7% had not dieted during that period (nondieters). Physical measurements, background characteristics, and weight-loss experiences were compared among the three groups, following an anthropometric measurement session and administration of a self-report questionnaire. The chronic and periodic dieters weighed an average of 12 lb more than the nondieters and were more likely to be obese. The dieters also had greater triceps skinfold thickness, arm circumference, arm muscle diameter, and arm muscle circumference measurements. Women in both dieting groups were more likely than the nondieting group to consider themselves as having been overweight during their childhood and adolescent years and to consider at least one parent overweight. The average age at the time of the first reducing diet was 16.2 years. The four most commonly tried weight-loss approaches were exercise, moderate calorie restriction, fasting/starvation, and diet pills or supplements. The major sources of information on reducing diets were magazines or newspapers and friends or relatives.

Adolescent↗
PubMed1998

Gonadal steroids and hypothalamic galanin and neuropeptide Y: role in eating behavior and body weight control in female rats.

The neuropeptides, galanin (GAL) and neuropeptide Y (NPY), based on studies in male rodents, are believed to have a role in controlling energy balance, both nutrient ingestion and metabolism. Whereas these peptides are also involved in reproduction, little is known about their specific function in energy balance in females. In rats consuming lab chow or macronutrient diets, measurements across the estrous cycle were taken of hypothalamic GAL and NPY, using RIA and immunohistochemistry; of the circulating hormones, estradiol, progesterone, and LH; and also of food intake and body weight. Levels of GAL and NPY peak during the proestrous phase of the female cycle when circulating estradiol and progesterone also rise. As previously reported for GAL, this peak is detected in two areas, the medial preoptic area (MPOA; +110%; P < 0.05) and the external zone of the median eminence (+57%; P < 0.05). In addition, this proestrous peak is seen in the paraventricular nucleus (PVN), specifically the anterior parvocellular portion (+35%; P < 0.05). Similarly, NPY rises during proestrous in the medial region of the PVN (+21%; P < 0.05) in addition to the MPOA (+78%; P < 0.05) and arcuate nucleus (+35%; P < 0.05). This peak in peptide levels is accompanied by an increase in caloric intake in rats receiving the lab chow diet and a specific increase in preference for fat in rats receiving macronutrient diets. Animals showing a preference for a fat-rich diet exhibit higher levels of GAL in the MPOA as well as the PVN and median eminence and also of NPY specifically in the MPOA. These peptides in the MPOA are similarly enhanced in animals with greater body fat, independent of diet. This evidence suggests that in the female rat, both GAL and NPY in the MPOA may contribute to the overeating and increased weight gain that occur during a fat-rich diet.

Animals↗
PubMed1990

Dexfenfluramine. Its place in weight control.

Dexfenfluramine, the dextrostereoisomer of fenfluramine, is a pure serotonin (5-hydroxytryptamine) agonist, apparently devoid of any additional antidopaminergic or sympathomimetic effects. The drug is approximately twice as effective as its racemic predecessor in reducing food intake in animals, and at a dose of 30 mg/day dexfenfluramine substantially modifies eating behaviour in man. Thus, a reduction in the motivation to eat and fewer snacking episodes were seen in volunteers treated with the drug, while total caloric and carbohydrate (but not protein) intakes were reduced in obese carbohydrate cravers. In clinical studies in obesity, dexfenfluramine combined with dietary support has produced mean weight reductions superior to those achieved with placebo over 3-month treatment periods. Importantly, the drug appears to maintain its weight-reducing effects for at least 12 months, without serious adverse effects. Dexfenfluramine appears to possess many of the properties of an 'ideal' pharmacotherapeutic agent for obesity. However, further long term clinical studies are required to confirm the promising efficacy and safety data obtained to date, and to further define the most appropriate indications for its use. Ideally, the drug should be used as adjunctive treatment in the clinical management of more severe cases of obesity, which are refractory to simpler supportive measures such as dietary or psychological counseling.

Animals↗
PubMed1989

Weight control and calorie expenditure: thermogenic effects of pre-prandial and post-prandial exercise.

The thermogenic effects of pre- and postprandial exercise was examined in seven lean active females. Energy expenditure was measured for 3 h via open circuit indirect calorimetry after four separate treatments: Exercise Only (25 min treadmill run at 60% VO2 max), Meal Only (910 kcal mixed meal), Exercise-Meal and Meal-Exercise. The thermogenic response to the Exercise-Meal treatment was similar to the Meal Only treatment. However, the Meal-Exercise treatment resulted in a greater energy expenditure than the Meal Only and Exercise-Meal treatments. The Exercise Only treatment showed the lowest thermogenic response. These data suggest that exercise following a meal would be more beneficial than exercise before a meal in increasing and maintaining an elevated energy expenditure.

Adult↗
PubMed1976

Group approach to weight control: behavior modification, nutrition, and health education.

We have had a positive experience using a modified approach to behavior modification of eating patterns, exercise, and activity, along with nutrition and health education. During the first year, forty-four adult patients completed the program, which was conducted in the out-patient clinic of a large hospital by a dietitian and a nurse practitioner. A cross-section of the patient population was admitted. The program had a pre-determined number of sessions, each of which was partially structured. When compared with the patients in individual therapy in our Nutrition Clinic, a more consistent weight loss in a shorter time was observed in the group participants. Whether the techniques described here will lead to sustained weight loss over time bears further study.

Adult↗