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Objective: To investigate the effect of a high‐energy (HE) diet on caloric intake, body weight, and related parameters in outbred male Sprague‐Dawley (SD) rats. Research Methods and Procedures: Twenty‐eight SD rats were fed either chow (C) for 19 weeks or HE diet for 14 weeks and then C for 5 weeks. Blood hormones and metabolites were assayed, and expression of uncoupling protein‐1 and hypothalamic energy‐balance‐related genes were determined by Northern blotting and in situ hybridization, respectively. Results: HE rats gained body weight more rapidly than C animals with a range of weight gains, but there was no evidence that weight gain was bimodally distributed. Caloric intake was transiently elevated after introduction of the HE diet. Transfer of HE rats back to C resulted in a drop in caloric intake, but a stable body weight. In terminal analysis, two of four dissected adipose tissue depots were heavier in rats that had previously been fed HE diet. Blood leptin, insulin, glucose, and nonesterified fatty acids were not different between the groups. Uncoupling protein‐1 mRNA was elevated in interscapular brown adipose tissue from HE rats. There was a trend for agouti‐related peptide mRNA in the hypothalamic arcuate nucleus to be higher in HE rats. Discussion: Contrary to other studies of the SD rat on HE diet, body weight and other measured parameters were normally distributed. There was no segregation into two distinct populations on the basis of susceptibility to diet‐induced obesity. This characteristic may be dependent on the breeding colony from which animals were sourced.  相似文献   

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Objective: Higher calcium and dairy intakes may be associated with lower body weights, but a mechanism in humans has yet to be elucidated. We compared the effects of a dairy‐based high‐calcium diet and a low‐calcium diet on macronutrient oxidation. Research Methods and Procedures: Subjects (10 men and nine women) consumed a low‐dairy (LD, ~one serving per day, ~500 mg Ca2+/d) or high‐dairy (HD, ~three to four servings per day, ~1400 mg Ca2+/d) energy balance diet for 1 week. Each diet condition was performed twice. On the 7th day, subjects were studied in a room calorimeter under one of four study conditions, applied in a randomized crossover design. Within each diet condition, subjects were studied under conditions of energy balance and acute energy deficit. The deficit (?600 kcal/d) was induced only for the 24 hours that subjects resided in the room and was achieved by a combination of caloric restriction and exercise. Results: Under energy balance conditions, there was no effect of diet treatment on respiratory quotient or 24‐hour macronutrient oxidation. Under energy deficit conditions, 24‐hour fat oxidation was significantly increased on the HD diet (HD with deficit = 136 ± 13 g/d, LD with deficit = 106 ± 7 g/d, p = 0.02). Discussion: Consumption of a dairy‐based high‐calcium diet increased 24‐hour fat oxidation under conditions of acute energy deficit. We hypothesize that these effects are due to an increased fat oxidation during exercise.  相似文献   

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Objective: Adiponectin influences insulin sensitivity (SI) and fat oxidation. Little is known about changes in adiponectin with changes in the fat content of eucaloric diets. We hypothesized that dietary fat content may influence adiponectin according to an individual's SI. Research Methods and Procedures: We measured changes in adiponectin, insulin, glucose, and leptin in response to high‐fat (HF) and low‐fat (LF) eucaloric diets in lean (n = 10) and obese (n = 11) subjects. Obese subjects were further subdivided in relation to a priori SI. Results: We found significantly higher insulin, glucose, and leptin and lower adiponectin in obese vs. lean subjects during both HF and LF. The mean group values of these measurements, including adiponectin (lean, HF 21.9 ± 9.8; LF, 20.8 ± 6.6; obese, HF 10.0 ± 3.3; LF, 9.5 ± 2.3 ng/mL; mean ± SD), did not significantly change between HF and LF diets. However, within the obese group, the insulin‐sensitive subjects had significantly higher adiponectin during HF than did the insulin‐resistant subjects. Additionally, the change in adiponectin from LF to HF diet correlated positively with the obese subjects’ baseline SI. Discussion: Although in lean and obese women, group mean values for adiponectin did not change significantly with a change in fat content of a eucaloric diet, a priori measured SI in obese subjects predicted an increase in adiponectin during the HF diet; this may be a mechanism that preserves SI in an already obese group.  相似文献   

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Longitudinal effects of a very low–carbohydrate (VLC) and a calorie‐matched high‐carbohydrate (HC) weight reduction diet were compared in dietary obese Sprague–Dawley rats exhibiting impaired glucose tolerance and insulin resistance. Obese rats were divided into weight‐matched groups: (i) VLC rats consumed an energy‐restricted 5% carbohydrate, 60% fat diet for 8 weeks, (ii) HC rats consumed an isocaloric 60% carbohydrate, 15% fat diet, and (iii) HF rats consumed a high‐fat diet ad libitum. HC and VLC rats showed similar reductions in body fat and hepatic lipid at the midpoint of the weight‐reduction program, indicating effects due to energy deficit. At the end point, however, HC rats showed greater reductions in total and percent body fat, hepatic lipid and intramuscular lipid than did VLC rats, suggesting that diet composition induced changes in the relative efficiencies of the HC and VLC diets over time. HC rats showed marked improvement in glucose tolerance at the midpoint and end point, whereas VLC rats showed no improvement. Impaired glucose tolerance in VLC rats at the end point was due to insulin resistance and an attenuated insulin secretory response. Glucose tolerance in energy‐restricted rats correlated negatively with hepatic and intramuscular lipid levels, but not visceral or total fat mass. These findings demonstrate that adaptations to diet composition eventually enabled HC rats to lose more body fat than VLC rats even though energy intakes were equal, and suggest that the elevated levels of hepatic and intramuscular lipid associated with VLC diets might predispose to insulin resistance and impaired glucose tolerance despite weight loss.  相似文献   

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Introduction – The obesity pandemic is multifactorial. Nutritional, pharmacologic and surgical interventions are limited in reach and efficacy, raising need for new therapeutics. Aims – Characterization of anorexigenic and cognitive effect and central mechanism of action of novel N-acylethanolamide derivatives. Methods – Sabra mice divided to similar experimental groups, injected IP with: oleyl-L-leucinolamide ( 1 A ), linoleyl-L-leucinolamide ( 4 A ), linoleyl-L-valinolamide ( 5 A ), oleyl-oxycarbonyl-L-valinolamide ( 1 B ), oleyl-oxycarbonyl-D-valinolamide ( 2 B ), oleylamine-carbonyl-L-valinolamide ( 3 B ), oleylamine-carbonyl-D-valinolamide ( 4 B ), and oleyl-L-hydroxyvalineamide ( 5 B ). Control group with vehicle. Body weight and food consumption followed for 39 days. Motor activity and cognitive function by open field test and eight-arm maze. Mice sacrificed and mechanism of action investigated by qPCR. The genes analyzed involved in energy balance and regulation of appetite. Catecholamines and serotonin evaluated. Results – Compounds 1 A , 5 A , 1 B – 4 B , caused significant weight loss of 4.2–5.6 % and 5 A , 1 B – 4 B , improved cognitive function following 8 i. p. injections of 1 mg/kg during 39 days, by different mechanisms. 5 A , 3 B and 4 B decreased food consumption, whereas 1 A , 5 A and 2 B increased motor activity. 1 A , 4 A , 1 B and 3 B elevated SIRT-1, associated with survival. POMC upregulated by 1 B and 2 B , CART by 1 B , 2 B and 1 A . NPY and CAMKK2 downregulated by 5 A . 4 B enhanced 5-HT levels. 4 A , 5 A , 1 B , 4 B , 5 B decreased FAAH, showing long lasting effect. Conclusions – These new compounds might be developed for the treatment of obesity and for improved cognitive function.  相似文献   

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Low‐carbohydrate diets have been associated with significant reductions in weight and HbA1c in obese, diabetic participants who received high‐intensity lifestyle modification for 6 or 12 months. This investigation sought to determine whether comparable results to those of short‐term, intensive interventions could be achieved over a 24‐month study period using a low‐intensity intervention that approximates what is feasible in outpatient practice. A total of 144 obese, diabetic participants were randomly assigned to a low‐carbohydrate diet (<30 g/day) or to a low fat diet (≤30% of calories from fat with a deficit of 500 kcal/day). Participants were provided weekly group nutrition education sessions for the first month, and monthly sessions thereafter through the end of 24 months. Weight, HbA1c, glucose, and lipids were measured at baseline and 6, 12, and 24 months. Of the 144 enrolled participants, 68 returned for the month 24 assessment visit. Weights were retrieved from electronic medical records for an additional 57 participants (total, 125 participants) at month 24. All participants with a baseline measurement and at least one of the three other measurements were included in the mixed‐model analyses (n = 138). The low‐intensity intervention resulted in modest weight loss in both groups at month 24. At this time, participants in the low‐carbohydrate group lost 1.5 kg, compared to 0.2 kg in the low‐fat group (P = 0.147). Lipids, glycemic indexes, and dietary intake did not differ between groups at month 24 (or at months 6 or 12) (ClinicalTrials.gov number, NCT00108459).  相似文献   

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This study tests the hypothesis that a high‐fat postnatal diet increases fat mass and reduces improved insulin sensitivity (IS) found in the low‐protein model of maternal undernutrition. Offspring from Wistar dams fed either a 20% (control (CON)) or 8% (low protein (LP)) protein diet during gestation and lactation were randomly assigned to a control (con) or cafeteria (caf) diet at weaning (21 days) until 3 months of age at which point IS was measured (hyperinsulinemic–euglycemic clamp). Fat mass, growth, energy intake (EI) and expenditure (EE), fuel utilization, insulin secretion, and leptin and adiponectin levels were measured to identify a possible role in any changes in IS. IS was increased in LP‐con in comparison to CON‐con animals. Cafeteria feeding prevented this increase in LP animals but had no effect in CON animals (insulin‐stimulated glucose infusion rates (GIRs; mg/min/kg); CON‐con: 13.9 ± 1.0, CON caf: 12.1 ± 2.1, LP‐con: 25.4 ± 2.0, LP‐caf: 13.7 ± 3.7, P < 0.05). CON‐caf animals had similar percent epididymal white adipose tissue (%EWAT; CON‐con: 1.71 ± 0.09 vs. CON‐caf: 1.66 ± 0.08) and adiponectin (µg/ml: CON‐con: 4.61 ± 0.34 vs. CON‐caf: 3.67 ± 0.18) except hyperinsulinemia and relative hyperleptinemia in comparison to CON‐con. Differently, LP‐caf animals had increased %EWAT (LP‐con: 1.11 ± 0.06 vs. LP‐caf: 1.44 ± 0.08, P < 0.05) and adiponectin (µg/ml: LP‐con: 5.38 ± 0.39 vs. LP‐caf: 3.75 ± 0.35, P < 0.05) but did not show cafeteria‐induced hyperinsulinemia or relative hyperleptinemia. An increased propensity to store visceral fat in LP animals may prevent the elevated IS in LP offspring.  相似文献   

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The intrinsic polysulfides shuttle, resulting from not only concentration‐gradient diffusion but also slow conversion kinetics of polysulfides, bears the primary responsibility for the poor capacity and cycle stability of lithium–sulfur batteries (LSBs). Here, it is first presented that enriched edge sites derived from vertical standing and ultrathin 2D layered metal selenides (2DLMS) can simultaneously achieve the thermodynamic and kinetic regulation for polysulfides diffusion, which is systematically elucidated through theoretical calculation, electrochemical characterization, and spectroscopic/microscopic analysis. When employed to fabricate compact coating layer of separator, an ultrahigh capacity of 1338.7 mA h g?1 is delivered after 100 cycles at 0.2 C, which is the best among the reports. Over 1000 cycles, the cell still maintains the capacity of 546.8 mA h g?1 at 0.5 C. Moreover, the cell exhibits outstanding capacities of 1106.2 and 865.7 mA h g?1 after 100 cycles at stern temperature of 0 and ?25 °C. The superior low‐temperature performance is appealing for extended practical application of LSBs. Especially, in view of the economy, the 2DLMS is recycled as an anode of lithium‐ion and sodium‐ion batteries after finishing the test of LSBs. The low‐cost and scalable 2DLMS with enriched egde sites open a new avenue for the perfect regulation of the sulfur electrode.  相似文献   

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Objective: We examined the effectiveness of sibutramine to modulate food intake and body composition in rats with two levels of adiposity imposed by the duration of their maintenance on a moderate-fat diet. Research Methods and Procedures: Male Sprague–Dawley rats were fed a 32% fat diet from weaning until 2 or 4 months of age, at which point, body fat was either 15% or 25%, respectively, as measured by DXA. Sibutramine (0.6 or 2 mg/kg, orally) was then given daily for 2 weeks. Results: Food intake and body weight decreased acutely in a dose-related manner in both groups with sibutramine treatment. In all rats, food intake suppression was attenuated after multiple days of sibutramine. Both 15%- and 25%-fat rats had a persistent decrease in weight gain over the 2-week period in response to sibutramine. The older, 25%-fat rats were more sensitive to sibutramine than the younger, 15%-fat rats with regard to the magnitude of overall food intake inhibition, decrease in body weight gain, and caloric efficiency. Despite these differences, sibutramine produced the same relative reductions in fat mass and had no effect on lean mass in the two groups. Discussion: Thus, sibutramine produced equivalent efficacy on carcass fat loss in both groups, despite less inhibition of feeding and body weight gain in leaner rats. Whether these changes are a result of the leaner rats being younger and on a steeper growth curve compared with older, fatter rats or whether this is a direct function of their level of adiposity remains to be determined.  相似文献   

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Lithium (Li) metal has attracted unprecedented attention as the ultimate anode material for future rechargeable batteries, but the electrochemical behavior (such as Li dendrites and gassing problems) in real Li metal pouch cells has received little attention. To achieve realistic high‐energy Li metal batteries, the designed solid electrolyte interface to suppress both Li dendrites and catastrophic gassing problems is urgently needed at cell level. Here, an efficient multifunctional silanization interface (MSI) is proposed for high‐energy Li metal pouch cells. Such an MSI not only guides uniform nucleation and growth of Li metal but also suppresses interfacial parasitic reactions between Li metal and electrolyte. As a result, under harsh conditions (negative to positive electrode capacity ratio of 2.96 and electrolyte weight to cathode capacity ratio of 2.7 g Ah?1), a long‐running lifespan (over 160 cycles with a capacity retention of 96% at 1 C), and low‐gassing behavior of realistic high‐energy Li metal pouch cell (1 Ah, 300 Wh kg?1) is achieved. This work opens a promising avenue toward the commercial applications of high‐energy Li metal batteries.  相似文献   

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Objective: Prior research has shown that fasting alternated with a diet of standard rodent chow and a 10% sucrose solution produces bingeing on the sucrose, but animals remain at normal body weight. The present study investigated whether restricted access to a highly palatable combination of sugar and fat, without food deprivation, would instigate binge eating and also increase body weight. Methods and Procedures: Male rats were maintained for 25 days on one of four diets: (i) sweet‐fat chow for 2 h/day followed by ad libitum standard chow, (ii) 2‐h sweet‐fat chow only 3 days/week and access to standard chow the rest of the time, (iii) ad libitum sweet‐fat chow, or (iv) ad libitum standard chow. Results: Both groups with 2‐h access to the sweet‐fat chow exhibited bingeing behavior, as defined by excessively large meals. The body weight of these animals increased due to large meals and then decreased between binges as a result of self‐restricted intake of standard chow following binges. However, despite these fluctuations in body weight, the group with 2‐h access to sweet‐fat chow every day gained significantly more weight than the control group with standard chow available ad libitum. Discussion: These findings may have implications for the body weight fluctuations associated with binge‐eating disorder, as well as the relationship between binge eating and the obesity epidemic.  相似文献   

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Objective: Signaling through adrenergic receptors (ARs) by norepinephrine (NE) and epinephrine (Epi) regulates weight gain when mice are fed a high‐fat diet (HFD) by controlling diet‐induced thermogenesis. Thus, one would predict that mice unable to make NE/Epi because of inactivation of the dopamine β‐hydroxylase gene (Dbh‐null mice) would have a propensity to become obese. We characterized the response of Dbh‐null and control mice to a HFD. Research Methods and Procedures: Dbh‐null and control mice were fed an HFD or a regular diet (RD) for 2 months. Body weight, adiposity, muscle triglyceride levels, and adipocyte size were measured, as were circulating leptin, adiponectin, triglyceride, glucose, and insulin levels. A glucose tolerance test was also preformed. Results: Dbh‐null mice gain weight normally on an HFD and have the same adiposity. Their serum triglyceride and leptin levels are normal, but adipocytes are ~30% smaller than controls. Dbh‐null mice maintain low blood glucose levels and glucose tolerance when exposed to the HFD in contrast to controls. Discussion: Complete lack of NE/Epi does not predispose to obesity. Because mice lacking all three βARs become obese on an HFD, an imbalance of signaling through α‐ and βARs seems to be responsible for obesity. Surprisingly, Dbh‐null mice maintain glucose tolerance.  相似文献   

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Meal composition is a contributing factor to fat gain. In this study, we investigated the relationship between postprandial nutrient balance, satiety, and hormone changes induced by a high‐fat meal vs. a moderate‐fat meal. Ten prepubertal obese boys (BMI z‐score range: 1.3–3.0) were recruited. Two meals (energy: 590 kcal) were compared: (i) high‐fat (HF) meal: 12% protein, 52% fat, 36% carbohydrates; (ii) moderate‐fat (MF) meal: 12% protein, 27% fat, 61% carbohydrates. Pre‐ and postprandial (5 h) substrate oxidation (indirect calorimetry), appetite (visual analogue scale), biochemical parameters and gastrointestinal hormone concentrations were measured. Carbohydrate balance was significantly (P < 0.001) lower (31.3 (5.7) g/5 h vs. 66.9 (5.9) g/5 h) and fat balance was significantly (P < 0.001) higher (11.5 (3.3) g/5 h vs. ?0.7 (2.9) g/5 h) after HF than MF meal. Appetite (area under the curve (AUC)) was significantly reduced after an MF than an HF meal (494 (55) cm·300 min vs. 595 (57) cm·300 min, P < 0.05). Postprandial triglyceride concentration (AUC) was significantly (P < 0.05) higher after an HF than an MF meal: 141.1 (30.3) mmol·300 min/l vs. 79.3 (23.8) mmol·300 min/l, respectively. Peptide YY (PYY), cholecystokinin (CCK), and ghrelin concentrations (AUC) were not significantly different after an HF and MF meal. Glucagon‐like peptide‐1 (GLP‐1) was significantly (P < 0.05) higher after an HF than after an MF meal (72.3 (9.8) ng/ml vs. 22.7 (7.6) ng/ml, respectively), but it did not affect subjective appetite. In conclusion, an MF meal induced a better postprandial metabolic nutrient balance, triglyceride levels, and appetite suppression than an HF meal. Gastrointestinal hormones were not related to clinically assessed hunger suppression after both meals.  相似文献   

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Low‐grade inflammation, which plays important roles in the development of fatal diseases, is commonly observed in obese people. However, this has not been evaluated in lean people, who have relatively increased mortality risk compared with people of normal weight. Here, we elucidate the association between systemic low‐grade inflammation and low body weight, with particular emphasis on aging. We examined the relationship between circulating C‐reactive protein (CRP) and BMI in a cross‐sectional study of 2,675 apparently healthy adults who had undergone a medical check‐up. Overall, subjects with low BMI (<21.0 kg/m2, n = 585) showed a favorable cardiovascular profile without being undernourished. In the elderly (≥55 years old), logarithmic CRP (LogCRP) showed a sigmoid curve against BMI with a base at BMI 21.0–22.9 kg/m2, but not against waist circumference (WC), even in nonsmokers. In contrast, in middle‐aged people, LogCRP showed an almost linear relationship with both BMI and WC. LogCRP levels in elderly nonsmokers with low BMI, but not normal or high BMI, were significantly higher than those in middle‐aged with corresponding BMI (P < 0.05). After adjustment for age, sex, smoking status, and weight change over the past 2 years, the adjusted means of LogCRP still had a similar sigmoid curve against BMI in the elderly. These results suggest that elderly people with low body weight may have subtle low‐grade inflammation irrespective of a favorable cardiovascular risk, which remains to be confirmed in further studies.  相似文献   

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