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1.
We investigated the effect of a combined carbohydrate and energy deficit in the regulation of food intake during 1 d. Seven lean, male subjects were studied in a crossover design. After 7 d of consuming a baseline diet (40% of energy as fat, 45% as carbohydrate, and 15% as protein), subjects were deprived of carbohydrate for 24 h; baseline amounts of fat and protein were consumed but only one-third of the baseline amount of carbohydrate. On the following outcome day, subjects were free to select ad libitum from a selection of either high-carbohydrate or low-carbohydrate food. On the baseline diet subjects consumed on average 10.9 +/- 1.7 MJ/d (carbohydrate: 305 +/- 49 g/d; fat: 116 +/- 18 g/d) and there was no difference in baseline intake between the two phases of the crossover study. During the deficit day, intake was reduced to 7.7 +/- 1.2 MJ/d [carbohydrate: 110 +/- 25 g/d (66% reduction); fat: 116 +/- 18 g/d]. On the outcome day, energy intake from high-carbohydrate foods was on average 10.5 MJ/d (carbohydrate: 430 +/- 112 g/d; fat: 48 +/- 20 g/d) compared with 16.6 MJ/d from high-fat foods (carbohydrate: 312 +/- 84 g/d; fat: 258 +/- 78 g/d). We conclude that the restoration of an energy deficit is not the main factor determining acute food intake. Rather, the data support the hypothesis that, under the conditions of our experiment, the intake of carbohydrate required to maintain carbohydrate balance was a more important factor in the regulation of acute food intake than was the restoration of energy deficit is not.  相似文献   

2.
Objective: Previous research showed a strong relation between response inhibition, overeating and overweight. It was shown that people with ineffective response inhibition are more susceptible to the temptations of palatable food, eat more and are more often overweight or obese. In addition the results of several studies suggest that what needs to be inhibited may be an affect-driven motivation for food. In the present longitudinal study, we therefore investigated the interplay of response inhibition and implicit preferences for snack foods in predicting weight gain. Design: In a sample of predominantly normal weight undergraduate female students, implicit preference for food, response inhibition, and body mass index (BMI) were measured. After 1 year, BMI was measured again. Main Outcome Measures: Weight gain of the participants over a 1-year period. Results and Conclusions: The results strongly confirmed our expectations: participants with strong implicit preferences for snack foods and low inhibitory capacity gained the most weight. These findings imply that ineffective response inhibition may render people vulnerable to excessive or impulsive behavior in general, but that the manifestation thereof is determined by domain-specific preferences or needs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

3.
To determine if persons with the Prader-Willi syndrome (PWS) have increased psychopathology when compared with matched controls, and whether there is a specific behavior phenotype in PWS, the behavior of 46 persons with PWS was compared with that of control individuals derived from a community sample (N = 454) of persons with mental retardation (MR). Behaviors were studied using the Developmental Behaviour Checklist, an instrument of established validity in the evaluation of behavioral disturbance in individuals with MR. PWS subjects were found to be more behaviorally disturbed than controls overall, and especially in antisocial behavior. In addition, some individual behaviors were more common in PWS subjects than controls. When these behaviors are considered together with findings from other studies using acceptably rigorous methods, a consensus behavior phenotype for PWS can be formulated. This will provide a valid foundation for studies of the mechanism of genetic pathogenesis of behavior in PWS.  相似文献   

4.
Hexarelin (Hex) is a synthetic hexapeptide with potent GH-releasing activity in both animals and men. Aim of this study was to evaluate the GH response to a maximal dose of Hex and GH-releasing hormone (GHRH) in a group of patients with Prader-Willi syndrome (PWS). Seven patients (4 boys and 3 girls, age 2.4-14.2 yr) with PWS, 10 prepubertal obese children (7 boys and 3 girls, age 7.5-12.0 yr), and 24 prepubertal short normal children (11 boys and 13 girls, age 5.9-13 yr) with body weight within +/- 10% of their ideal weight were studied. All subjects were tested on two occasions with GHRH 1-29 at the dose of 1 microgram/Kg i.v., and with Hex at the dose of 2 micrograms/Kg i.v. In the PWS patients the GH response to GHRH (peak = 6.4 +/- 2.0 micrograms/l, p < 0.0001; AUC = 248 +/- 70 micrograms min/l, p < 0.0001) was significantly lower than that observed in the short normal children and similar to that observed in the obese children. In the PWS children the GH response to Hex (peak = 7.5 +/- 1.6 micrograms/l; AUC = 309 +/- 53) was similar to that observed after GHRH and significantly lower than that observed in the obese children (p < 0.05). The results of this study show that PWS patients have a blunted GH response to the administration of a maximal dose of Hex. Whether these findings reflect a more severe pituitary GH deficiency in PWS than in obese children or a deranged hypothalamic regulation of GH secretion need further investigation.  相似文献   

5.
OBJECTIVES: To evaluate energy expenditure after three isoenergetic meals of different nutrient composition and to establish the relationship between the thermic effect of food (TEF), subsequent energy intake from a test meal and satiety sensations related to consumption. DESIGN: The study employed a repeated measures design. Ten subjects received, in a randomized order, three meals of 2331+/-36 kJ (557+/-9 kcal). About 68% of energy from protein in the high protein meal (HP), 69% from carbohydrate in the high carbohydrate meal (HC) and 70% from fat in the high fat meal (HF). SETTING: The experiments were performed at the University of Milan. Subjects: Ten normal body-weight healthy women. METHODS: Energy expenditure was measured by indirect calorimetric measurements, using an open-circuit ventilated-hood system; intake was assessed 7h later by weighing the food consumed from a test meal and satiety sensations were rated by means of a satiety rating questionnaire. RESULTS: TEF was 261+/-59, 92+/-67 and 97+/-71 kJ over 7 h after the HP, HC and HF meals, respectively. The HP meal was the most thermogenic (P < 0.001) and it determined the highest sensation of fullness (P=0.002). There were no differences in the sensations and thermic effect between fat and carbohydrate meals. A significant relationship linked TEF to fullness sensation (r=0.41, P=0.025). Energy intake from the test meal was comparable after HP, HC and HF meals. CONCLUSIONS: Our results suggest that TEF contributes to the satiating power of foods.  相似文献   

6.
BACKGROUND: Hypersecretion of insulinotropic factors such as glucose dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1(7-36)amide (GLP-1) have been postulated to account for the hyperinsulinaemia of obesity. AIMS: To examine the role of GLP-1 and GIP in obese women and matched controls. SUBJECTS: Six lean and six obese women subjects matched for age. METHODS: The gut hormone, plasma glucose, and serum triglyceride responses were studied over 180 minutes after oral carbohydrate and fat meals. Heparin (10,000 units) was given intravenously at 120 minutes. RESULTS: There was pronounced attenuation of plasma GLP-1 secretion to oral carbohydrate in the obese compared with lean subjects but no such difference in response to oral fat load. There were no differences in the plasma GIP responses to carbohydrate or fat feeding. There was an apparent fall in plasma GLP-1 values in all subjects after administration of heparin. CONCLUSION: Postprandial GLP-1 secretion in response to oral carbohydrate is considerably attenuated in obese subjects. The cause of this attenuation of GLP-1 secretion is not known although we suggest that both this fall and the overall reduction in GLP-1 values in obese subjects may be related to an increase in plasma non-esterified fatty acids.  相似文献   

7.
BACKGROUND: Prader-Willi syndrome (PWS) is a genetic disorder characterized by mental retardation, appetite dysregulation, and a high risk for obsessive-compulsive disorder (OCD). Microscopic abnormalities of the hypothalamus have been described in PWS, and oxytocin has been implicated in both appetite regulation and OCD. METHODS: Oxytocin and arginine vasopressin (AVP) were measured in the cerebrospinal fluid of 5 subjects with PWS (2 male, 3 female) and in 6 normal control subjects (all female). RESULTS: CSF oxytocin was elevated in PWS (9.2 +/- 3.9 pmol/L) as compared to normal control subjects (5.1 +/- 0.9 pmol/L, p = 0.045), a finding that was more significant when excluding male subjects from analysis (p = 0.02). AVP was not significantly different between the groups as a whole. CONCLUSIONS: These data provide further evidence for hypothalamic and oxytocinergic dysfunction in PWS. The associations between oxytocin, appetite regulation, and obsessive compulsive symptomatology in PWS warrant further investigation.  相似文献   

8.
The spontaneous growth of 315 patients (109 girls and 208 boys) with Prader-Willi syndrome (PWS) was analysed in a mixed longitudinal and cross-sectional manner. 33 patients were seen in the department between 1970 and 1994; height and weight of 76 patients from Germany were evaluated by means of a questionnaire with detailed measuring instructions, and 206 definite cases were added from the literature. Mean ( SD) length of newborn babies with PWS was 50.2+/-2.8 cm (145 boys) and 48.9 3.3 cm (79 girls). Mean weight at birth was 2945 570 g in boys and 2782+/-594 g in girls. During the 1st year, the children's growth was nearly normal, thereafter short stature was present in approximately 50% of PWS patients. Between 3 and 13 years of age, the 50th percentile for height in PWS is roughly identical with the 3rd percentile in healthy controls. Body weight was normal for all boys and girls during the first 2 years. Thereafter, a rapid weight gain occurred; after an age of 10 years weight-for-height index in nearly all patients exceeded the normal range. The extent of pubertal growth was reduced for the group. Mean adult height was 161.6+/-8.1 cm (23 males) and 150.2+/-5.5 cm (21 females). Head circumference for age was normal for boys and girls. CONCLUSION: Reference data on spontaneous development of growth and weight gain of children with Prader-Willi syndrome are described allowing a better counselling of patients and parents.  相似文献   

9.
The Prader-Willi syndrome (PWS) is associated with a tendency to self-injury and a reduced sensitivity to painful stimuli. Somatosensory functions were studied in 5 children aged 11-13 years with PWS. Tactual perception in the hands (stereognosis) was apparently normal in 4 of them. Sensory nerve conduction velocities in the median nerve and latencies for sensory evoked potentials were similar in the PWS subjects and in 10 healthy controls indicating a preserved myelinisation of sensory nerve fibers in PWS. Sensory nerve action potential amplitudes in the PWS group were on an average only 40-50% of normal size (p = 0.03), suggesting a reduced number of normal axons in the median nerve. The results may be relevant for the impaired pain sensitivity in PWS because similar neurographic findings and a low density of peripheral nerve fibers have been reported in patients with hereditary or congenital insensitivity to pain.  相似文献   

10.
OBJECTIVE: To present evidence on the control of the size of fatty meals in the context of the result of interactions of orosensory positive-feedback and postingestive negative-feedback mechanisms activated by fat stimuli in rodent models of feeding and of obesity. METHOD: We examined the effects of orosensory stimuli and postingestive stimuli in Sprague-Dawley rats, and in the genetically obese Zucker (fa/fa) rat. We used the sham feeding rat preparation to isolate the orosensory stimulating and postingestive satiating properties of oils. The negative-feedback satiating properties of fats were elicited by intestinal infusions of fats. The Zucker rat is an animal model of obesity with abnormal control of meal size and increased intake of fats. Using this model we further examined the interaction of orosensory and postingestive stimuli in the control of meal size. RESULTS: The orosensory properties of fats are sufficient to drive sham feeding and are not dependent on the postabsorptive metabolic consequences of oils in normal and Zucker rats. The satiating action of fats must act at preabsorptive sites because reduction of intake occurs before absorption of fat. The satiating potency of fats is dependent upon their specific chemical conformation and is mediated by endogenous cholecystokinin and afferent fibers of the abdominal vagus. We have found that oils produce significantly more orosensory positive feedback in obese Zucker rats than in lean rats in experimental tests of preference. This is probably the major abnormal mechanism responsible for the increased preference for fats that is characteristic of obese rats because we have not identified any significant decrease in the postingestive satiating potency of fats in obese Zucker rats. CONCLUSIONS: Fat intake is controlled by both orosensory and postingestive stimuli in normal and genetically obese rodents. In the Zucker rat the investigation of this model of genetic obesity has produced data that is congruent with the preference for high fat foods in obese people and suggests further experiments directed toward a deeper understanding of the controls of fat intake and how they are disordered.  相似文献   

11.
Two experiments, with a total of 120 undergraduates, investigated the relationships among degree of obesity, nearness to set point for adipose tissue mass, and responsiveness to taste. In Exp I, Ss rated milkshakes varying in sweetness intensity. Overweight and normal weight Ss did not have significantly different detection thresholds or preference ratings. However, overweight Ss worked longer than normals to obtain their most preferred substance. Exp II varied the ease of tasting the milkshake. Preference and food intake of moderately overweight Ss were significantly more influenced by tastes that they found positive and negative than was the preference of normal weight or obese Ss. The ease of ingesting the taste substance also significantly influenced preference and food intake of the moderately obese only. Nearness to set point, operationally defined as weight stability for 2 yrs, had no significant effects. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

12.
Adipose tissue, the logical target component in weight reduction regimens, was measured in five obese subjects during weight reduction, and in four normal weight controls. The two compartment model of Ljunggren, consisting of adipose tissue (AT) and adipose tissue-free mass (AFM), was further developed by finding experimental values for total water, extracellular water (ECW), lipid, and cell solids in 16 biopsied subjects. The AFM was estimated from body potassium content (40K counting) by use of an age/sex specific constant for the K content in the fat free body. Five obese subjects maintained for 46 days on regimens averaging 800 kcal/day had initial AT from 48% to 60% of body weight compared with AT 27% to 46% in four normal controls. Weight reductions averaged 17.4 kg (12% of initial weight), with approximately equal reductions in adipose tissue, adipose-free mass, and water. Initial fluid compartment ratios in the obese were unusually high (ECW:ICW in AFM was 0.74 +/- 0.23 [S.D.] compared with 0.42 +/- 0.05 in normals); these values returned toward normal (to 0.59 +/- 0.06) with weight reduction. The fact that it was possible to disclose a hitherto unappreciated abnormality of hydration in the adipose-free mass of obese subjects and its change toward normal with weight reduction, suggests that the adipose:adipose-free model may have a special utility when body composition measurements are used to monitor the effects of weight reduction regimens on various body constituents.  相似文献   

13.
BACKGROUND: We designed a data-based semi-quantitative food frequency questionnaire to clarify the relationship between food intake and lifestyle-related diseases among middle-aged Japanese. METHODS: A total of 351 middle-aged individuals were recruited to a one-day weighed diet record survey in 1994. In all, 586 foods were consumed. Intake of 31 nutrients including energy, protein, fat, carbohydrate, vitamins, minerals and dietary fiber by food was computed by multiplying the weight of food consumed by its nutrient content. First, 252 foods with up to 90 cumulative % contribution to nutrient intake were selected. Of these, foods having apparently the same/similar nutrient content were combined into 206 foods by research dietitians. Next, 183 foods with up to 0.90 cumulative multiple regression coefficient and 90 cumulative % contribution were chosen. At this stage an additional food grouping was made. RESULTS: Finally, 102 foods/recipes were included in the questionnaire: rice (2 items), bread and noodles (11), eggs, milk and dairy products (10), soybean, soybean products and other beans (7), meat including beef, pork and chicken (12), fish (5), other fish, shellfish and fish products (10), green-yellow vegetables (8), other vegetables and mushrooms (7), edible roots (2), seaweeds (3), seeds (2), fruits (8), beverages (7) and confectioneries (8). The frequencies were classified into eight categories. Portion size was calculated for the respective foods largely from the one-day weighed diet record. CONCLUSIONS: The developed semi-quantitative food frequency questionnaire substantially covered the intake of 31 nutrients and may be competent to rank middle-aged Japanese efficiently.  相似文献   

14.
15.
This study examined implicit and explicit attitudes toward high-fat foods in obese (n = 30) and normal-weight controls (n = 31). The Implicit Association Test (A. G. Greenwald, D. E. McGee, & J. L. K. Schwartz, 1998) was used to measure the differential association of the 2 target categories--high-fat vs. low-fat food words--with an attribute dimension (positive vs. negative). Results suggest that obese people are characterized by a significantly stronger implicit negative attitude toward high-fat foods than are normal-weight controls. This implicit negative attitude is contradictory to their preferences and behavior: Several studies indicate that obese people prefer and consume high-fat foods. Apparently, obese people like the taste of high-fat foods but not the fat content itself, not only on the explicit but also on the implicit level. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

16.
Diet-induced obesity was treated with a high carbohydrate, low fat diet and/or increased voluntary exercise in mice. All mice had free access to food and water during the two stage experiment. In Stage 1, 20 female mice were fed a high carbohydrate diet and 50 were made obese by consumption of a diet providing 40.8% of energy from fat. At the end of Stage 1, obese mice had significantly greater body fat stores (22.9 +/- 0.9 g/100 g body wt) than mice fed the high carbohydrate diet (12.9 +/- 1.2) (P < 0.001), yet there was no significant difference in lean body mass. In Stage 2, half of the mice were given activity wheels to increase their voluntary activity and half of the obese mice were switched to a high carbohydrate diet resulting in six groups with treatment designations of obese or lean; exercise or nonexercise, and carbohydrate or fat diets. Body fat was significantly reduced by consumption of the high carbohydrate diet (P < 0.005) and by exercise (P < 0.001), but neither treatment affected lean body mass. Exercising mice consumed significantly more energy than nonexercising mice, yet experienced a decrease in body fat and energy stores.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

17.
Plasma leptin concentrations were measured every 20 min for 24 h in eight normal weight women and in eight upper body and eight lower body obese women matched for body mass index. The circadian rhythm of leptin, which could mathematically be described by a cosine, was characterized by an acrophase just after midnight in all subjects. The amplitude of a cosine fit as well as the average 24-h leptin concentration were increased by 280% and 420%, respectively, in obese compared to normal weight women. All characteristics of leptin concentration profiles were similar in upper body and lower body obese women, except for a significantly higher amplitude in the lower body obese group. Visceral and sc body fat depots were measured using magnetic resonance imaging in all three groups. Average 24-h leptin concentrations were strongly correlated with sc fat (r = 0.84), whereas visceral fat was not an independent predictor of the plasma leptin level. A loss of 50% of the overweight was associated with a 55% decrease in the average 24-h leptin concentrations in obese women (95% confidence interval, 12.3, 26.6), whereas the characteristics of the circadian rhythm of leptin remained unchanged. Finally, it was observed that a fasting plasma leptin concentration is not an acceptable indicator of the average leptin concentration over 24 h.  相似文献   

18.
Leptin is a protein encoded by the ob gene that is expressed in adipocytes and regulates eating behavior via central neuroendocrine mechanisms. Serum leptin levels have been shown to correlate with weight and percent body fat in normal and obese individuals; however, it is not known whether the regulation of leptin is normal below a critical threshold of body fat in chronic undernutrition. We investigated serum leptin levels in 22 women, aged 23 +/- 4 yr, with anorexia nervosa. Duration of disease, weight, BMI, percent body fat, and serum leptin levels were determined for each patient. Nutritional status was assessed further by caloric intake and measurement of insulin and insulin-like growth factor I (IGF-I) levels. Twenty-three healthy women, aged 23 +/- 4 yr, taking no medications, with normal menstrual function and body mass index (BMI) between 20-26 kg/m2 (mean, 23.7 +/- 1.7 kg/m2), served as a control population for comparison of leptin levels. Subjects with anorexia nervosa were low weight (BMI, 16.3 +/- 1.6 kg/m2; normal, 20-26 kg/m2) and exhibited a striking reduction in percent body fat (7 +/- 2%; normal, 20-30%). The mean serum leptin level was significantly decreased in subjects with anorexia nervosa compared with that in age- and sex-matched controls of normal body weight (5.6 +/- 3.7 vs. 19.1 +/- 8.1 ng/mL; P < 0.0001). Serum leptin levels were correlated highly with weight, as expressed either BMI (r = 0.66; P = 0.002) or percent ideal body weight (r = 0.68; P = 0.0005), body fat (r = 0.70; P = 0.0003), and IGF-I (r = 0.64; P = 0.001), but not with caloric intake or serum levels of estradiol or insulin in subjects with anorexia nervosa. The correlation between leptin and body fat was linear, with progressively lower, but detectable, leptin levels measured even in patients with less than 5% body fat, but was not significant when the effects of weight were taken into account. In contrast, the correlation between leptin and IGF-I remained significant when the effects of weight, body fat, and caloric intake were taken into account. In normal controls, leptin correlated with BMI (r = 0.55; P = 0.007) and IGF-I (r = 0.44; P < 0.05), but not with fat mass. These data demonstrate that serum leptin levels are reduced in association with low weight and percent body fat in subjects with anorexia nervosa compared to normal controls. Leptin levels correlate highly with weight, percent body fat, and IGF-I in subjects with anorexia nervosa, suggesting that the physiological regulation of leptin is maintained in relation to nutritional status even at an extreme of low weight and body fat.  相似文献   

19.
A plasma insulin and amino acid-mediated mechanism is thought to modulate brain serotonin concentration, thereby regulating carbohydrate consumption on a meal to meal basis. It has been suggested that obesity is associated with a defect in the appetite control system. Furthermore, post-absorptive plasma levels of several amino acids are increased in obese subjects, which is ascribed to obesity-associated insulin resistance and/or hyperinsulinemia. We studied breakfast-induced changes in plasma ratios of tryptophan to other large neutral amino acids and associated differences in macro-nutrient composition of lunch food in normal weight and obese human subjects. The study was randomized, double blind and cross-over with a 2 x 2 factorial design with drug/placebo and type of breakfast as factors. Nineteen healthy, non-obese (body mass index (BMI) 22.5 +/- 1.9 kg/m2, mean +/- s.d.) and 19 obese (BMI 34.7 +/- 6.2 kg/m2) female volunteers were treated with either 60 mg fluoxetine (FXT), a serotonin re-uptake blocker specifically acting in the brain, or placebo for four days with a wash-out period between treatments of four weeks. The subjects received either a carbohydrate (CHO) breakfast (80 g maltodextrin, 300 kcal) or a protein-rich (PROT) breakfast (60% milk protein and 40% CHO, 300 kcal) on two consecutive days (days 4 and 5 of each treatment period). Plasma glucose, insulin and amino acids were measured at several time points after breakfast. Three hours after breakfast, subjects were able to choose from 29 different food items. Total energy content and weight of lunch food and energy percentage of each macronutrient were calculated.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

20.
A low metabolic rate for a given body size and body composition and a low ratio of fat to carbohydrate oxidation predict body weight gain. Such metabolic traits could also explain, in part, the propensity of previously obese (postobese) individuals to regain weight after dieting. We studied 11 postobese volunteers (4 males, 7 females; aged 43 +/- 13 y, weighing 80.6 +/- 10.2 kg, with 30 +/- 7% body fat; x +/- SD) who lost 57 +/- 38 kg (23-139 kg) over 14 +/- 12 mo (6-48 mo) on various diet programs and had maintained this weight loss for > or = 2 mo (2-72 mo; 21 +/- 27 mo). After > or = 2 d of a weight-maintenance diet on a metabolic ward, 24-h energy expenditure and ratio of fat to carbohydrate oxidation were measured in a respiratory chamber. Compared with a control group (n = 110) with similar physical characteristics (aged 43 +/- 14 y, weighing 79.5 +/- 11.4 kg, with 30 +/- 12% body fat), [sequence: see text] postobese individuals had similar energy expenditures adjusted for fat-free mass, fat mass, age, and sex, but significantly higher respiratory quotients over 24 h (0.883 +/- 0.026 compared with 0.863 +/- 0.024, P < 0.01) and during sleep, 10 h after the last meal (0.894 +/- 0.063 compared with 0.845 +/- 0.055). These results suggest that postobese individuals have low rates of fat oxidation that may explain their propensity to regain weight.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

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