Oral supplementation with carbohydrate- and branched-chain amino acid-enriched nutrients improves postoperative quality of life in patients undergoing hepatic resection

The long-term outcomes of branched-chain amino acid (BCAA) administration in patients undergoing hepatic resection remain unclear. The aim of this study is to assess the impact of oral supplementation with BCAA-enriched nutrients on postoperative quality of life (QOL) in patients undergoing liver resection. A prospective randomized clinical trial was conducted in 96 patients undergoing hepatic resection. Patients were randomly assigned to receive BCAA supplementation (AEN group, n = 48) or a conventional diet (control group, n = 48). Postoperative QOL and short-term outcomes were regularly and continuously evaluated in all patients using a short-form 36 (SF-36) health questionnaire and by measuring various clinical parameters. This study demonstrated a significant improvement in QOL after hepatectomy for liver neoplasm in the AEN group based on the same patients’ preoperative SF-36 scores (P < 0.05). Perioperative BCAA supplementation preserved liver function and general patient health in the short term for AEN group patients compared to those not receiving the nutritional supplement. BCAA supplementation improved postoperative QOL after hepatic resection over the long term by restoring and maintaining nutritional status and whole-body kinetics. This study was registered at (registration number: NCT00945568).     

Preoperative oral carbohydrate treatment attenuates immediate postoperative insulin resistance

Postoperative insulin resistance is a well-characterized metabolic state that has been shown to correlate with the length of postoperative stay in hospital. Preoperative intravenous or oral carbohydrate treatment has been shown to attenuate the development of postoperative insulin resistance measured 1 day after surgery. To study the effects of preoperative oral carbohydrate treatment on postoperative changes in insulin resistance and substrate utilization, in the absence of postoperative confounding factors, 15 patients were double-blindly treated with either a carbohydrate-rich beverage (12.5%) (n = 8) or placebo (n = 7) before undergoing total hip replacement surgery. Insulin sensitivity, endogenous glucose release, and substrate oxidation rates were measured before and immediately after surgery. Whole body insulin sensitivity decreased by 18% in the treatment group vs. 43% in the placebo group (P < 0.05, Student's t-test for unpaired data). In both groups, the major mechanism of insulin resistance was an inhibition of insulin-induced nonoxidative glucose disposal after surgery. The better preservation of insulin sensitivity in the treatment group was attributable to a less reduced glucose disposal in peripheral tissues and increased glucose oxidation rates.     

术前口服碳水化合物对胃癌术后患者的影响

目的:研究胃癌患者术前口服碳水化合物的安全性及对术后胰岛素抵抗影响。方法:选取胃下部癌病理诊断明确的患者32例,取得知情同意后按照随机双盲的试验,参与者麻醉前2-3小时口服碳水化合物或安慰剂,术前4小时及术后即刻抽取静脉血测定血糖、胰岛素及C-反应蛋白浓度,通过HOMA发计算出术前术后胰岛素抵抗指数、胰岛素敏感指数、胰岛素分泌指数,并将两组进行比较。结果:与口服安慰剂组相比较,术前口服碳水化合物组的血糖、胰岛素、C-反应蛋白及胰岛素抵抗指数更低,且两组患者术后胰岛素敏感性均下降,但口服碳水化合物组的胰岛素敏感性较安慰剂组高。结论:术前2-3小时口服碳水化合物是安全有效的,且能明显术后即刻胰岛素抵抗状态,应作为术前常规处理。     

术前口服碳水化合物对胃癌术后患者的影响

目的：研究胃癌患者术前口服碳水化合物的安全性及对术后胰岛素抵抗影响。方法：选取胃下部癌病理诊断明确的患者32例,取得知情同意后按照随机双盲的试验,参与者麻醉前2-3小时口服碳水化合物或安慰剂,术前4小时及术后即刻抽取静脉血测定血糖、胰岛素及C-反应蛋白浓度,通过HOMA发计算出术前术后胰岛素抵抗指数、胰岛素敏感指数、胰岛素分泌指数,并将两组进行比较。结果：与口服安慰剂组相比较,术前口服碳水化合物组的血糖、胰岛素、C-反应蛋白及胰岛素抵抗指数更低,且两组患者术后胰岛素敏感性均下降,但口服碳水化合物组的胰岛素敏感性较安慰剂组高。结论：术前2-3小时口服碳水化合物是安全有效的,且能明显术后即刻胰岛素抵抗状态,应作为术前常规处理。     

An amino acid mixture improves glucose tolerance and lowers insulin resistance in the obese Zucker rat

The purpose of this investigation was to test an amino acid mixture on glucose tolerance in obese Zucker rats [experiment (Exp)-1] and determine whether differences in blood glucose were associated with alterations in muscle glucose uptake [experiment (Exp)-2]. Exp-1 rats were gavaged with either carbohydrate (OB-CHO), carbohydrate plus amino acid mixture (OB-AA-1), carbohydrate plus amino acid mixture with increased leucine concentration (OB-AA-2) or water (OB-PLA). The glucose response in OB-AA-1 and OB-AA-2 were similar, and both were lower compared to OB-CHO. This effect of the amino acid mixtures did not appear to be solely attributable to an increase in plasma insulin. Rats in Exp-2 were gavaged with carbohydrate (OB-CHO), carbohydrate plus amino acid mixture (OB-AA-1) or water (OB-PLA). Lean Zuckers were gavaged with carbohydrate (LN-CHO). Fifteen minutes after gavage, a radiolabeled glucose analog was infused through a catheter previously implanted in the right jugular vein. Blood glucose was significantly lower in OB-AA-1 compared to OB-CHO while the insulin responses were similar. Glucose uptake was greater in OB-AA-1 compared with OB-CHO, and similar to that in LN-CHO in red gastrocnemius muscle (5.15 ± 0.29, 3.8 ± 0.27, 5.18 ± 0.34 µmol/100 g/min, respectively). Western blot analysis showed that Akt substrate of 160 kDa (AS160) phosphorylation was enhanced for OB-AA-1 and LN-CHO compared to OB-CHO. These findings suggest that an amino acid mixture improves glucose tolerance in an insulin resistant model and that these improvements are associated with an increase in skeletal muscle glucose uptake possibly due to improved intracellular signaling.     

术前合理管理对老年下肢骨折全麻手术患者血糖水平、血流动力学及应激因子的影响

摘要 目的：探讨术前合理管理对老年下肢骨折全麻手术患者血糖水平、血流动力学及应激因子的影响。方法：选择2017年6月-2019年6月我院收治的120例拟行全麻手术治疗的老年下肢骨折患者,随机分为两组。观察组（60例）给予术前合理管理,对照组（60例）给予传统术前管理。对比两组围术期血糖水平、血流动力学以及应激因子指标差异。结果：两组平均动脉压（MAP）、心输出量（CO）、体外循环阻力（SVR）、胸腔液体含量（TFC）、血糖、胰高血糖素、胰岛素、C肽、皮质醇 （Cor）、肾素（Rn）和促肾上腺皮质激素（ACTH）整体比较差异具有统计学意义（P＜0.05）,观察组麻醉后或术后各时点MAP、CO、TFC、胰岛素、C肽高于对照组,SVR、血糖、胰高血糖素、Cor、Rn、ACTH低于对照组（P＜0.05）。观察组术后首次排气时间、首次下床活动时间、术后住院时间短于对照组（P＜0.05）,口渴饥饿、术后感染发生率低于对照组（P＜0.05）。结论：术前合理管理可稳定老年下肢骨折全麻手术患者围术期血流动力学和血糖水平,降低应激因子水平和术后并发症风险,加快术后患者的康复。     

Beyond lipids, pharmacological PPARalpha activation has important effects on amino acid metabolism as studied in the rat

PPARalpha agonists have been characterized largely in terms of their effects on lipids and glucose metabolism, whereas little has been reported about effects on amino acid metabolism. We studied responses to the PPARalpha agonist WY 14,643 (30 micromol x kg(-1) x day(-1) for 4 wk) in rats fed a saturated fat diet. Plasma and urine were analyzed with proton NMR. Plasma amino acids were measured using HPLC, and hepatic gene expression was assessed with DNA arrays. The high-fat diet elevated plasma levels of insulin and triglycerides (TG), and WY 14,643 treatment ameliorated this insulin resistance and dyslipidemia, lowering plasma insulin and TG levels. In addition, treatment decreased body weight gain, without altering cumulative food intake, and increased liver mass. WY 14,643 increased plasma levels of 12 of 22 amino acids, including glucogenic and some ketogenic amino acids, whereas arginine was significantly decreased. There was no alteration in branched-chain amino acid levels. Compared with the fat-fed control animals, WY 14,643-treated animals had raised plasma urea and ammonia levels as well as raised urine levels of N-methylnicotinamide and dimethylglycine. WY 14,643 induced changes in a number of key genes involved in amino acid metabolism in addition to expected effects on hepatic genes involved in lipid catabolism and ketone body formation. In conclusion, the present results suggest that, in rodents, effects of pharmacological PPARalpha activation extend beyond control of lipid metabolism to include important effects on whole body amino acid mobilization and hepatic amino acid metabolism.     

Insulin Requirements in Patients With Type 2 Diabetes Undergoing Bariatric Surgery in the Inpatient Setting and Upon Discharge: A Single-Center Retrospective Analysis of Insulin Management Strategies

ObjectiveRapid improvement in blood glucose (BG) after weight-loss surgery (WLS) can make postoperative glucose management challenging in patients with type 2 diabetes mellitus (T2DM). Our study examined the safety and efficacy of insulin management strategies during hospitalization and after discharge following WLS.MethodsThis single-center retrospective cohort study included 160 adult patients with type 2 diabetes mellitus undergoing WLS. Patients with glycated hemoglobin A1C (HbA1C) level <7% (53 mmol/mol) and not on antihyperglycemic medications or metformin monotherapy were excluded. BG and insulin dosing during hospitalization and at 2-week follow-up, and impact of preoperative HbA1C level were analyzed.ResultsMean age was 46.3 years. Median preoperative HbA1C level was 8% (64 mmol/mol). Postoperatively, most patients received basal insulin plus sliding-scale insulin (SSI; 79/160, 49%) or SSI alone (77/160, 48%). The initial postoperative basal dose was 0.23 units/kg/day. The median basal insulin dose at discharge was 61% lower than preoperative dose. At 2-week follow-up, 34 of 44 patients (77%) had BG levels between 70-200 mg/dL and 1 of 44 (2.2%) had BG levels >200 mg/dL, with no hypoglycemia. Patients with HbA1C level >9% (75 mmol/mol) had higher BG on admission and during hospitalization, required higher insulin doses while hospitalized, and were more frequently discharged on insulin.ConclusionSSI is effective in managing BG in some patients immediately after WLS. However, about half of the patients may require basal insulin at doses similar to those required by other inpatients. Preoperative hyperglycemia may affect inpatient insulin needs and BG. Low-dose basal insulin appears safe and effective upon discharge for select patients.     

Betaine Down Regulates Apelin Gene Expression in Cardiac and Adipose Tissues of Insulin Resistant Diabetic Rats Fed by High-Calorie Diet

Apelin is a newly discovered peptide that its serum level increases in diabetic patients with cardiovascular dysfunction. Recent studies indicate the beneficial actions of betaine in reducing the cardiovascular and metabolic complications, however data related to its effect on adipocytokine expression is limited. The aim of this study was to evaluate the effect of betaine supplementation on Apelin gene expression in cardiac muscle and adipose tissue of insulin resistance, diabetic rats fed by a high calorie diet. To induce insulin resistance rats were fed with high fat/high carbohydrate diet for five weeks and then 30 mg/kg STZ was injected intraperitoneally. After confirming of diabetes incidence (serum glucose above 7.5 mmol/l) the animals were treated with 1 % betaine in drinking water for 28 days. At days 14 and 28 after treatment, animals were euthanized and Apelin gene expression was evaluated by real time PCR and western blot in heart and adipose tissues. Serum levels of insulin, Apelin and glucose and HOMA–IR were also measured. Our results showed that feeding of rats by a high calorie diets caused insulin resistance, which was manifested by elevated plasma insulin, glucose and Apelin levels and also HOMA–IR. Apelin gene expression in heart and adipose tissues were significantly increased simultaneously with the progression of diabetes. Betaine supplementation decreased serum Apelin and down regulated Apelin expression in adipose tissue and cardiac muscle, particularly at day 28 of treatment. We concluded that betaine might improve metabolic and cardiovascular complications in diabetic patients by regulation of Apelin expression and secretion.     

Long-term fatty liver-induced insulin resistance in orotic acid-induced nonalcoholic fatty liver rats

We investigated whether fatty liver preceded insulin resistance or vice versa using a long-term orotic acid (OA)-induced nonalcoholic fatty liver disease (NAFLD) model without the confounding effects of obesity and hyperlipidemia and explored the role of the liver in insulin resistance. Male Wistar rats were fed with or without OA supplementation for 30, 60, and 90 days. The NAFLD group showed increased liver lipid at 30, 60, and 90 days; glucose intolerance was noted at 60 and 90 days. Furthermore, partial liver proteins and gene expressions related to upstream signaling of insulin were decreased. However, the liver glycogen content was elevated, and gluconeogenesis genes expressions were obviously decreased at 90 days. The occurrence of fatty liver preceded insulin resistance in OA-induced NAFLD without the interference of obesity and hyperlipidemia, and hepatic insulin resistance may not play a conclusive role in insulin resistance in this model.     

Branched-chain amino acid-enriched diet: effects on insulin secretion and cellular immune aggression

Several reports have demonstrated that high-protein diets may have beneficial effects on experimental models of diabetes and have raised the possibility that branched-chain amino acids could play a role in these protective effects. We investigated the effect of a normoproteic, branched-chain amino acid-enriched diet (experimental diet) on insulin secretion from C57BL/6N mice transferred with splenocytes from diabetic syngeneic donors. Mice previously fed with the experimental or control diet received three intraperitoneal injections, every other day, of 5 x 107 viable mononuclear splenocytes obtained from control or diabetic donors. Results showed that mice fed with the experimental diet and transferred with "diabetic" splenocytes presented: i) normoglycemia, and (ii) significantly higher levels in both phases of glucose-induced insulin secretion and normal values of arginine-glucose-induced insulin secretion. To evaluate the in vitro cellular immune aggression, dispersed mouse islet cells were co-cultured with splenocytes from syngeneic diabetic mice. First, dispersed islet cells from mice on the experimental or control diet were co-cultured with splenocytes from control or diabetic mice on a commercial diet. In the presence of "diabetic splenocytes, dispersed islet cells from mice on the experimental diet presented a significantly lower in vitro cellular immune aggression. On the other hand, "diabetic" splenocytes from mice fed with the experimental diet produced a significantly reduced cellular immune aggression on dispersed islet cells. Our results showed that feeding branched-chain amino acids increased the capacity of beta cells to withstand a functional assault and diminished the extent of in vitro cellular immune aggression.     

Effects of Insulin on Free Amino Acids in Plasma and the Role of the Amino Acid Metabolism in the Etiology of Diabetic Microangiopathy

To investigate if alterations of the amino acid metabolism may play a more important role in the etiology of diabetic microangiopathy than hitherto recognized, free amino acids in plasma were measured by means of high-performance liquid chromatography (HPLC) in healthy individuals (REF) and patients with insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM). Isoleucine and leucine in IDDM were within normal limits, whereas they were significantly higher in NIDDM (P < 0.01 and P < 0.001, respectively). This was not due to age differences. In order to evaluate the impact of insulin on amino acid metabolism, amino acids were also measured in pregnant women (PREG) undergoing glucose tolerance tests as a screening for pregnancy diabetes and in patients with polycystic ovary syndrome (PCO) undergoing euglycemic insulin clamp tests. Insulin considerably reduced the amino acid concentration. Isoleucine and leucine were particularly depressed. On the whole there was strong covariance between the three branched-chain amino acids, isoleucine, leucine, and valine (P < 0.0001). There was no covariance between amino acid and glucose or HbAlc concentrations, A protein meal strongly stimulated insulin production (+55 mIU/liter), whereas a galactose meal revealed only a minor increase in insulin response (+ 12 mIU/liter) in contrast to a tolerance test with the same amount of glucose (+ 67 mIU/liter). It is concluded that disturbed amino acid metabolism may be a more important causative factor in the etiology of diabetic microangiopathy than hitherto recognized and, in addition, that this may affect the therapeutic approach in both IDDM and NIDDM patients.     

Once-Daily Insulin Glargine Versus 6-Hour Sliding Scale Regular Insulin for Control of Hyperglycemia after a Bariatric Surgical Procedure: A Randomized Clinical Trial

ObjectiveTo determine whether once-daily insulin glargine could provide better glycemic control after an abdominal surgical procedure than the traditional use of sliding scale regular insulin (SSRI).MethodsBecause 20% to 30% of patients undergoing gastric bypass have a history of overt diabetes and another 5% to 10% are estimated to have impaired glucose tolerance, we chose to study these patients. We treated 81 patients with postoperative blood glucose levels of more than 144 mg/dL after a Roux-en-Y gastric bypass surgical procedure. They were randomized to receive either SSRI or insulin glargine either directly or after initial intravenous insulin infusion in the intensive care unit (ICU).ResultsOverall, the mean blood glucose level after SSRI therapy was 154 ± 33 mg/dL, and the mean blood glucose value after insulin glargine treatment was 134 ± 30 mg/dL (P < 0.01). The mean blood glucose level for patients first treated with intravenous insulin infusion in the ICU was 125 mg/dL, in comparison with 145 mg/dL in the non-ICU patients whose treatment began directly with 0.3 U/kg of insulin glargine. Of 926 blood glucose measurements, only 3 were less than 60 mg/dL.ConclusionIn this study, control of postoperative hyperglycemia was significantly better with use of insulin glargine in comparison with SSRI therapy, and hypo-glycemia was very infrequent. (Endocr Pract. 2007;13: 225-231)     

Studies on Acholeplasma laidlawii grown on branched-chain fatty acids

Acholeplasma laidlawii B was grown on the branched-chain fatty acids, 14-methylpentadecanoic acid and 14-methylhexadecanoic acid, and the straight-chain palmitic acid. The incorporation of the branched-chain fatty acids was very effective; more than 90% of the fatty acids of the lipids of this organism consisted of the branched-chain constituents. A somewhat smaller amount (81%) was found in the cells grown with palmitic acid. Differential scanning calorimetry of the isolated membranes showed that distinct lipid phase transitions occurred in between 15 and 31 °C for the 14-methylpentadecanoic acid, 11 and 29 °C for the 14-methylhexadecanoic acid, and 14 and 36 °C for the palmitic acid-enriched membranes. Freeze-fracture electron microscopy showed that the lipid phase transitions were accompanied by particle aggregation only in the case of palmitic acid-enriched membranes. When the branched-chain acid-enriched membranes were quenched from temperatures below the onset of the lipid phase transition, a random distribution of particles on both fracture faces of the membrane was observed. The membranes were incubated with pig pancreatic phospholipase A₂ at various temperatures. Below the onset of the lipid phase transition phosphatidylglycerol was not accessible for this enzyme in palmitate-enriched membranes. However, a fast hydrolysis of 60–75% of the phosphatidylglycerol could be measured in the branched-chain acid-enriched membranes at temperatures below the onset of the lipid phase transition. The residual phosphatidylglycerol could be hydrolyzed at a slower, temperature-dependent rate. The observations show that lipids containing branched-chain acids undergo a cooperative lipid phase transition which does not result in a tight packing of the lipids of the bilayer below the phase transition.     

Comparison of the effect of semisynthetic human insulin and porcine insulin on glucose kinetics, plasma free fatty acid and amino acid levels in man

The effect of semisynthetic human insulin on hepatic glucose output, peripheral glucose clearance, plasma levels of C-Peptide, free fatty acids and amino acids was compared with purified pork insulin using the glucose clamp technique. 8 normal overnight-fasted subjects received intravenous infusions of either human or porcine insulin at 20 mU/m2.min(-1) during 120 min achieving plasma insulin levels of approximately equal to 50 mU/l. Plasma glucose levels were maintained at euglycaemia by variable rates of glucose infusion. Hepatic glucose production measured by continuous infusion of 3-(3) H-glucose was similarly suppressed by both insulins to rates near zero. The metabolic clearance rate of glucose increased during infusion of human insulin by 120%, C-peptide levels decreased by 41% and plasma FFA concentrations fell by 74%. The respective changes during infusion of pork insulin were similar, 118%, 48% and 72%. Both insulins decreased the plasma levels of branched-chain amino acids, tyrosine, phenylalanine, methionine, serine and histidine similarly. Thus, the results demonstrate that semisynthetic human and porcine insulin are aequipotent with respect to suppression of hepatic glucose output, stimulation of glucose clearance, inhibition of insulin secretion, lipolysis and proteolysis.     

Dietary carbohydrate-to-protein ratio affects TOR signaling and metabolism-related gene expression in the liver and muscle of rainbow trout after a single meal

Most teleost fish are known to require high levels of dietary proteins. Such high-protein intake could have significant effects, particularly on insulin-regulated gene expression. We therefore analyzed the effects of an increase in the ratio of dietary carbohydrates/proteins on the refeeding activation of the Akt-target of rapamycin (TOR) signaling pathways in rainbow trout and the effects on the expression of several genes related to hepatic and muscle metabolism and known to be regulated by insulin, amino acids, and/or glucose. Fish were fed once one of three experimental diets containing high (H), medium (M), or low (L) protein (P) or carbohydrate (C) levels after 48 h of feed deprivation. Activation of the Akt/TOR signaling pathway by refeeding was severely impaired by decreasing the proteins-to-carbohydrates ratio. Similarly, postprandial regulation of several genes related to glucose (Glut4, glucose-6-phosphatase isoform 1), lipid (fatty acid synthase, ATP-citrate lyase, sterol responsive element binding protein, carnitine palmitoyltransferase 1, and 3-hydroxyacyl-CoA dehydrogenase), and amino acid metabolism (serine dehydratase and branched-chain α-keto acid dehydrogenase E2 subunit) only occurred when fish were fed the high-protein diet. On the other hand, diet composition had a low impact on the expression of genes related to muscle protein degradation. Interestingly, glucokinase was the only gene of those monitored whose expression was significantly upregulated by increased carbohydrate intake. In conclusion, this study demonstrated that macro-nutrient composition of the diet strongly affected the insulin/amino acids signaling pathway and expression pattern of genes related to metabolism.     

Insulin and branched-chain amino acid depletion during mouse preimplantation embryo culture programmes body weight gain and raised blood pressure during early postnatal life

Mouse maternal low protein diet exclusively during preimplantation development (Emb-LPD) is sufficient to programme altered growth and cardiovascular dysfunction in offspring. Here, we use an in vitro model comprising preimplantation culture in medium depleted in insulin and branched-chain amino acids (BCAA), two proposed embryo programming inductive factors from Emb-LPD studies, to examine the consequences for blastocyst organisation and, after embryo transfer (ET), postnatal disease origin. Two-cell embryos were cultured to blastocyst stage in defined KSOM medium supplemented with four combinations of insulin and BCAA concentrations. Control medium contained serum insulin and uterine luminal fluid amino acid concentrations (including BCAA) found in control mothers from the maternal diet model (N-insulin + N-bcaa). Experimental medium (three groups) contained 50% reduction in insulin and/or BCAA (L-insulin + N-bcaa, N-insulin + L-bcaa, and L-insulin + N-bcaa). Lineage-specific cell numbers of resultant blastocysts were not affected by treatment. Following ET, a combined depletion of insulin and BCAA during embryo culture induced a non sex-specific increase in birth weight and weight gain during early postnatal life. Furthermore, male offspring displayed relative hypertension and female offspring reduced heart/body weight, both characteristics of Emb-LPD offspring. Combined depletion of metabolites also resulted in a strong positive correlation between body weight and glucose metabolism that was absent in the control group. Our results support the notion that composition of preimplantation culture medium can programme development and associate with disease origin affecting postnatal growth and cardiovascular phenotypes and implicate two important nutritional mediators in the inductive mechanism. Our data also have implications for human assisted reproductive treatment (ART) practice.     

Longitudinal Adaptations to Very Low–carbohydrate Weight‐reduction Diet in Obese Rats: Body Composition and Glucose Tolerance

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.