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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Liquid diets based on the AIN-76 formula are described. The diets employ xanthan gum as a stabilizer. Information is provided on how these diets may be modified to meet the requirements of a particular experiment (e.g., variations in water content, type of protein or carbohydrate or fat, etc.). These diets are superior to widely used diets with regard to nutritional adequacy, cost, ease of preparation, versatility, stability, osmolality, and use of natural ingredients. An experiment is described which compares the effects of feeding rats a solid diet or a liquid diet prepared three different ways. The results confirm that a properly prepared liquid diet can produce overweight and obesity.
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PMID:Practical liquid diets for rats: effects on growth. 357 1

Studies were undertaken to analyze the role of moisture content of foods in producing dietary obesity. Female CD rats consumed more energy when offered a sucrose solution and plain water to drink than when they were only given plain water, regardless of the sugar content of their diet (0-65%). This suggested that the overeating that commonly occurs when sucrose solutions are offered may not be due to sucrose per se. In subsequent experiments, rats were fed modified AIN-76 diets high in sucrose, starch or fat for 28-42 d. For some rats, the diet was liquefied by adding water to make a 32% suspension. Plain drinking water was always available. Rats fed high carbohydrate liquid diets, with or without solid diet, consumed 8-15% more energy than rats fed solid diet only. Rats fed liquid diets also gained 43-206% more weight than did rats fed solid diets. Analysis of carcass composition revealed that the liquid diets increased body fat. For high fat diets, the results were more complicated. Addition of water to a low cellulose, high fat diet did not increase adiposity, whereas addition of water to a high cellulose, high fat diet did increase adiposity. These results suggest that the obesity-inducing effects of feeding sugar solutions or cafeteria diets may be due, in part, to the high water content of these foods.
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PMID:Feeding a liquid diet increases energy intake, weight gain and body fat in rats. 369 90

A purified moderately high fat diet has been developed to examine diet-induced obesity in rats. Male Sprague-Dawley rats were fed this or an AIN-76A diet for 15 wk and energy metabolism indices were monitored. Food intake, body weight and water balance indices were recorded on a weekly or daily basis. Over the 15-wk period, rats fed the experimental diet diverged into two groups differing in the rate of body weight gain. Animals were labeled as "gainers" or "resisters" depending on their susceptibility to obesity. Following the dietary period, rats were decapitated and trunk blood was collected for glucose and insulin measurements. Gainers consumed slightly more energy than resisters over the experimental period (P < 0.05), but due to greater fecal energy loss, absorbed energy did not differ. Hence gainers became obese without significantly altered energy retention. Urinary creatinine, urea nitrogen and water balance were not different between the groups and consequently could not explain body weight differences. Further, gainers had significantly greater plasma glucose concentration than controls, indicating a potential for these animals to become diabetic. Results suggest metabolic differences must account for the divergence in weight gain observed in the two groups. The dietary model characterized in this study should provide a useful tool to study diet-induced obesity and to determine its underlying mechanism.
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PMID:Development and characterization of a purified diet to identify obesity-susceptible and resistant rat populations. 796 1

Evidence of the validity and accuracy of dual x-ray absorptiometry (DXA) to measure soft-tissue composition of laboratory rats with altered body composition associated with nutritional perturbations is lacking. We compared DXA determinations made in prone and supine positions with measurements of chemical composition of 49 male, weanling Sprague-Dawley rats that were fed the basal AIN-93 growth diet, were fed the basal diet modified to contain 30% fat, were fasted for 2 d, were limit fed 6 g of the basal diet daily for 1 wk, or were treated with furosemide (10 mg/kg intraperitoneally 2 h before DXA). DXA produced similar estimates of body mass and soft-tissue composition in the prone and supine positions. DXA estimates of body composition were significantly correlated with reference composition values (R(2) = 0.371-0.999). DXA discriminated treatment effects on body mass, fat-free and bone-free mass, fat mass, and body fatness; it significantly underestimated body mass (1% to 2%) and fat-free and bone-free mass (3%) and significantly overestimated fat mass and body fatness (3% to 25%). The greatest errors occurred in treatment groups in which body mass was diminished and body hydration was decreased. These findings suggest that DXA can determine small changes in fat-free, bone-free mass in response to obesity and weight loss. Errors in DXA determination of fat mass and body fatness associated with extra corporeal fluid and dehydration indicate the need for revision of calculation algorithms for soft-tissue determination.
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PMID:Validation of dual x-ray absorptiometry for body-composition assessment of rats exposed to dietary stressors. 1144 99

Rats fed a high-fat diet before and during lactation have difficulty initiating lactation and have high pup mortality rates, low milk production and, consequently, poor pup growth. To determine if these adverse outcomes can be mitigated with dietary changes made after delivery, obese Sprague-Dawley rats (who had previously been fed a high-fat diet [AIN-93M, modified to contain 35% fat, w/w]) were assigned at parturition to continue to be fed this diet (HF) or switched to free access to a corresponding low-fat (LF) diet (AIN-93M, 4% fat w/w) or switched to the LF diet and restricted to consuming only 75% of ad libitum intake (LF/R). Dams lost weight during lactation, but weight loss was much less in the LF group (19g) than in the other two groups (47 and 59g, HF and LF/R, respectively). There was no appreciable change in body water; body fat decreased by about half in all groups, but most substantially in the LF/R group. Compared with the HF group, milk production was 50% higher in the LF group and 12% lower in the LF/R group. Milk lipid concentration tended to be higher and milk water concentration lower in the HF compared with the other two groups. Growth of the litters of the LF dams was significantly higher than both HF and LF/R dams. These results indicate that switching to a low-fat diet mitigates the negative effects of obesity and continued high-fat feeding on lactational performance and pup growth. Consumption of restricted quantities of a low-fat diet negatively affected milk production and failed to improve pup growth, despite the dams' mobilization of body fat in support of lactation.
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PMID:A low-fat diet but not food restriction improves lactational performance in obese rats. 1178 70

Several epidemiological studies have supported the concept that high energy intake, obesity, and/or hyperinsulinemia are risk factors for colon cancer. Previously, it was shown that Zucker obese rats are more sensitive to chemically induced colon cancer than their lean counterparts. The present study investigated whether moderate (20-25%) dietary energy restriction (ER) would attenuate colon carcinogenesis in the Zucker obese rat model. Six-week-old Zucker obese (fa/fa) rats and lean (Fa/Fa) rats received s.c. injections of azoxymethane at a dose of 10 mg/kg body weight once weekly for 2 weeks. A week later, obese rats (n = 16) were assigned to an ER diet (Ob-ER group), based on a low-fat AIN-93G semisynthetic diet. The remaining obese and lean rats (n = 16 rats/group) were fed the low-fat diet ad libitum (Ob group and Ln group, respectively). All rats were euthanized after 8 weeks, and their colons were assessed for aberrant crypt foci (ACF; n = 8/group) or for the expression of transforming growth factor (TGF)-beta and cyclooxygenase (COX) isoforms at the protein and mRNA transcript levels (n = 8/group). Ob rats had a higher number of advanced ACF (crypt multiplicity >or=7) than Ln rats. Dietary ER significantly reduced the appearance of advanced ACF in Ob-ER rats without significantly affecting the blood insulin level or body weights. TGF-beta and COX isoforms were differentially expressed in the colonic mucosae of Ob and Ln rats. Dietary ER significantly reduced TGF-beta1/beta2 and COX-1/2 protein expression in obese rats. This study is the first to demonstrate that moderate ER attenuated TGF-beta and COX protein expression and the carcinogenic process in Zucker obese rats. These findings provide insights leading to the proposal that the mechanism(s) underlying the early events of colon carcinogenesis in Zucker obese rats may extend beyond the role of excessive body weight and hyperinsulinemia per se.
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PMID:Energy restriction reduces the number of advanced aberrant crypt foci and attenuates the expression of colonic transforming growth factor beta and cyclooxygenase isoforms in Zucker obese (fa/fa) rats. 1458 51

The current study sought to examine whether leptin injections following a weight reduction in diet-induced obese rats would reduce both the enhanced food intake and body weight (BW) regain observed during the refeeding phase. Female Wistar rats (n = 100, 20 per group) were divided into 5 groups: (1) LEP rats were fed a high-fat (HF) diet (35% wt/wt) for 8 weeks to induce obesity and were then food-restricted (50% ad libitum) with a fortified high-fat diet for 2 weeks to induce a 20% BW loss. These rats were then refed the HF diet ad libtum for another 11 weeks. They were given leptin injections (200 microg/kg BW, twice daily, intraperitoneally ) for 19 days concomitant with the onset of refeeding. (2) SAL rats were treated in the same manner as LEP rats except that they were given saline injections; (3) PF rats were treated like SAL rats except that they were pair-fed with the LEP rats; (4) HFC rats were fed HF diet ad libitum; and (5) LFC rats were fed a low-fat (LF) diet (AIN-93M) ad libitum. Ten rats from each group were killed after leptin treatment and at the end of the study. Food and caloric intakes were monitored, and body composition and plasma glucose, insulin, and leptin levels were assessed at death. Leptin injections after a weight reduction briefly reduced energy intake during the first week only. After 19 days of treatment and to the end of the study, LEP and SAL rats were similar in energy intake, BW (LEP: 393 +/- 11.2 g, SAL: 371 +/- 14.1; difference not significant [NS]) and total body fat percent (LEP: 19.3 +/- 1.5, SAL: 17.6 +/- 1.5; NS). Leptin treatment induced hyperinsulinemia and insulin resistance. All of the metabolic abnormalities observed at the end of treatment period disappeared at the end of the study (8 weeks post-leptin injection). We conclude that bolus leptin injections to manipulate leptin circadian rhythm in diet-induced obese rats after a weight reduction caused temporary insulin resistance and hyperinsulinemia, and were ineffective in influencing food intake, BW, and fat content. Leptin resistance was evident following 1 week of treatment in this study. Leptin treatment had no effect on body fat content both short-term and long-term. Exogenous leptin treatment may, in the long run, increase leptin resistance in diet-induced obese animals. Hence, long-term leptin treatment may not be beneficial to obese individuals consuming a HF diet.
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PMID:Augmenting leptin circadian rhythm following a weight reduction in diet-induced obese rats: short- and long-term effects. 1516 29

The effects of soybean isoflavones with or without probiotics on tissue fat deposition, plasma cholesterol, and steroid and thyroid hormones were studied in SHR/N-cp rats, an animal model of obesity, and were compared to lean phenotype. We tested the hypothesis that probiotics by promoting the conversion of isoflavone glycosides to their metabolically active aglycone form will have a synergistic effect on body fat, cholesterol metabolism, and the endocrine system. Obese and lean SHR/N-cp rats were fed AIN-93 diets containing 0.1% soy isoflavone mixture, 0.1% probiotic mixture, or both together. Different fat tissues were teased and weighed. Plasma was analyzed for cholesterol and steroid and thyroid hormones. In both phenotypes, isoflavones lowered fat deposition in several fat depots. Probiotics alone had no significant effect on fat depots. Isoflavones lowered total, LDL, and HDL cholesterol in lean rats, but in obese rats isoflavones lowered only total and LDL cholesterol. Isoflavones also lowered many of the steroid hormones involved in lipid metabolism but had no significant effect on thyroid hormones. Probiotics had no significant effect on cholesterol or hormones. Thus, our data show that soy isoflavones also lower plasma cholesterol and that this hypocholesterolemic effect appears to be due in part to the modulation of steroid hormones. Probiotics do not seem to enhance the effect of isoflavones.
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PMID:Effects of soybean isoflavones, probiotics, and their interactions on lipid metabolism and endocrine system in an animal model of obesity and diabetes. 1554 49

Seeds of Sinapis alba Linn. (commonly called yellow or white mustard) and their components have been reported to possess anticancer properties. In this study, we evaluated the efficacy of a novel mucilaginous fraction of mustard seeds in inhibiting colonic preneoplastic changes in animal models of sporadic and obesity-associated colon cancer. In two separate studies, male Sprague-Dawley or female Zucker obese rats, injected with azoxymethane (15 or 10 mg/kg body wt. once a week for 2 weeks, respectively), were fed AIN-93G diets with or without 5% mustard mucilage (MM) (w/w) for 8 weeks. Our aim was to measure the ability to modulate the number of aberrant crypt foci (ACF), putative preneoplastic lesions of the colon. The data were classified into total numbers of ACF and large ACF (crypt multiplicity of 4 or more). We report here that 5% MM significantly (p<0.05) decreased the number of total (approximately 21% inhibition) and large (approximately 50% inhibition) ACF in the colons of Sprague-Dawley rats compared to that in untreated controls. In addition, 5% MM supplemented diet significantly lowered (p<0.05) the number of total (approximately 63% inhibition) and large (approximately 60% inhibition) colonic ACF in Zucker obese rats compared to untreated obese rats, and had no effect on fasting plasma cholesterol or triglyceride levels. These results demonstrate the possible role of MM as a functional food against sporadic and obesity-associated colon cancer, and provide impetus to conduct research to understand the underlying mechanism(s) of action.
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PMID:Novel mucilage fraction of Sinapis alba L. (mustard) reduces azoxymethane-induced colonic aberrant crypt foci formation in F344 and Zucker obese rats. 1718 81

We examined the effect of okara on the prevention of obesity in mice. A modified AIN-76 diet with a high fat content (14.1% of crude fat) was used as a basal diet. Male ICR mice were fed ad libitum with the basal diet or a dried okara-supplemented basal diet (10, 20, or 40%) for 10 weeks. The okara intake dose-dependently suppressed the development of body weight and epididymal white adipose tissue (EWAT), and prevented an increase of plasma lipids, including total cholesterol, LDL cholesterol, and non-esterified fatty acid. The okara intake also prevented steatosis in the liver. Real-time RT-PCR revealed that the okara intake induced down-regulation of the fatty acid synthetase gene and up-regulation of the cholesterol 7 alpha-hydroxylase (CYP7A1) gene in the liver. We also found that the okara intake caused a marked reduction in the expression of leptin and TNF-alpha genes in EWAT. Our results suggest that okara is beneficial in preventing obesity.
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PMID:Okara, soybean residue, prevents obesity in a diet-induced murine obesity model. 1734 37


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