High-carbohydrate Group Research Articles

Nutritional ketosis for mild cognitive impairment in Parkinson's disease: A controlled pilot trial

IntroductionGlucose hypometabolism and insulin resistance increase risk for and accelerate progression in Parkinson's disease and neurocognitive disorders. We conducted a proof of concept trial to determine whether ketogenesis, a metabolic adaptation induced by dietary carbohydrate restriction, can improve cognitive performance in Parkinson's disease patients with mild cognitive impairment. MethodsWe enrolled patients with mild cognitive impairment associated with Parkinson's disease in an eight-week nutritional intervention with random assignment to either high-carbohydrate consumption typical of the Western dietary pattern (n = 7) or to a low-carbohydrate, ketogenic regimen (n = 7). We assessed changes in cognitive performance as well as motor function, anthropometrics, and metabolic parameters. ResultsRelative to the high-carbohydrate group, the low-carbohydrate group demonstrated improvements in lexical access (p = 0.02, Cohen's f effect size = 0.76) and memory (p = 0.01, f = 0.87) and as well as a trend for reduced interference in memory (p = 0.06, f = 0.60). The low-carbohydrate group also exhibited reduced body weight (p < 0.0001, f = 1.89) and increased circulation of beta-hydroxybutyrate (p = 0.01, f = 0.90). Change in body weight was strongly associated with memory performance (p = 0.001). Motor function was not affected by the intervention. ConclusionNutritional ketosis enhanced cognitive performance in Parkinson's disease-associated mild cognitive impairment in this pilot study. This metabolic intervention and its mechanisms deserve further investigation in the context of neurodegeneration.

Different strategies of grass carp (Ctenopharyngodon idella) responding to insufficient or excessive dietary carbohydrate

As typical herbivorous fish, grass carp possesses greater capability to utilize carbohydrate than carnivorous and omnivorous fish. However, mechanism of carbohydrate utilization in herbivorous fish was unclear. This study is intended to investigate response of grass carp to insufficient or excessive dietary carbohydrate. Grass carp accepted isonitrogenous diets with different carbohydrate levels (15.90, 21.81 and 45.45 g 100 g−1) were cultured. After 8 weeks, weight gain and feed intake were highest in fish fed with medium-carbohydrate diet compared with others. Gene expression data indicated that expressions of glucose-6-phosphatase (G6Pase) were down-regulated and gene expressions of glycogen synthase (GS) were up-regulated in fish accepted lower-carbohydrate diet. In high-carbohydrate group, glucose catabolism was increased by enhanced expressions of glucokinase genes (GK). Meanwhile, fatty acid synthase (FAS) and acetyl coenzyme-A carboxylase (ACC1) genes were significantly up-regulated and lipoprotein lipase and carnitine palmitoyltransferase 1 (CPT1) genes expressions were down-regulate, inducing more lipid deposition. Subsequently, serum cholesterol and total lipid contents were significantly increased, and then induced appetite suppression through up-regulation of leptin and anorexigenic genes expressions. Furthermore, depressed food intake caused lower growth rate in grass carp with excessive carbohydrate intake.

The association of protein and carbohydrate intake with successful aging: a combined analysis of two epidemiological studies.

Previous studies have reported associations between levels of protein and carbohydrate intake with several health outcomes. Yet, their effect on successful (or healthy) aging remains unknown. The purpose of the present work was to investigate the association of protein and carbohydrate intake levels with successful aging. A cross-sectional analysis was carried out on the participants of two epidemiological studies; the ATTICA and the MEDIS studies. Anthropometrical, clinical and socio-demographic characteristics, dietary habits, and lifestyle parameters were derived through standard procedures. Successful aging was evaluated using a validated index (SAI) composed of 10 health-related social, lifestyle and clinical characteristics. SAI levels were lower in low protein-high carbohydrate diet group (B = - 0.08, p = 0.04), but higher in high protein-high carbohydrate group (B = 0.06, p = 0.04), as compared to low protein and low carbohydrate diet, in participants living in insular areas. Protein-carbohydrate diet was not associated with SAI (all p's > 0.05) among participants living in urban areas (p for diet-study interaction < 0.001). A high protein diet seems to be beneficial for older islanders in terms of successful aging; stating a hypothesis for a potential diet-environmental interaction that may be related to the quality of foods consumed and, consequently the sources of nutrients.

The interaction between apolipoprotein B insertion/deletion polymorphism and macronutrient intake on lipid profile and serum leptin and ghrelin levels in type 2 diabetes mellitus patients.

We aimed to study whether macronutrient intake could modify the association between ApoB Ins/Del and lipid profile, and serum leptin and ghrelin in type 2 diabetes mellitus (T2DM) patients. In this study, 700 T2DM patients were recruited. Anthropometric, biochemical and molecular data were collected, and Diet was assessed using a food frequency questionnaire. The interactions were tested using ANCOVA. Del-allele carriers with high-MUFA and carbohydrate (≥ 12 and ≥ 54% of energy, respectively) had significantly higher TG (P = 0.04) and LDL-C (P = 0.02) compared to Ins/Ins homozygotes, and these were not significant in subjects with low-MUFA and -carbohydrate (< 12 and < 54%, respectively). A significant interaction was observed between ApoB Ins/Del and diet on TG in both unadjusted (P = 0.03) and adjusted models (model 2 and 3, P = 0.04 and P = 0.04, respectively), and on LDL-C only in adjusted models (model 2 and 3, P = 0.03 and P = 0.029, respectively). Besides, Del-allele carriers with protein, SFA, MUFA and n-3PUFA of ≥ 14, 9, 12 and 0.6%, respectively, had a significant increase in their serum leptin than Ins/Ins homozygotes (P < 0.05). However, these associations were not significant between the two genetic groups in subjects with low intakes of protein, SFA, MUFA and n-3PUFA. Moreover, Del-allele carriers with low carbohydrate (< 54%) had significantly higher leptin and ghrelin than Ins/Ins homozygotes (P < 0.05), however, in high-carbohydrate group, leptin and ghrelin were not significantly lower. These findings indicate that the interaction between ApoB Ins/Del and dietary intake of MUFA, SFA, n-3PUFA, carbohydrate and protein could modulate the serum levels of TG, LDL-C, leptin and ghrelin in T2DM patients.

Keto-adaptation enhances exercise performance and body composition responses to training in endurance athletes

BackgroundLow-carbohydrate diets have recently grown in popularity among endurance athletes, yet little is known about the long-term (>4wk) performance implications of consuming a low-carbohydrate high fat ketogenic diet (LCKD) in well-trained athletes. MethodsTwenty male endurance-trained athletes (age 33±11y, body mass 80±11kg; BMI 24.7±3.1kg/m2) who habitually consumed a carbohydrate-based diet, self-selected into a high-carbohydrate (HC) group (n=11, %carbohydrate:protein:fat=65:14:20), or a LCKD group (n=9, 6:17:77). Both groups performed the same training intervention (endurance, strength and high intensity interval training (HIIT)). Prior to and following successful completion of 12-weeks of diet and training, participants had their body composition assessed, and completed a 100km time trial (TT), six second (SS) sprint, and a critical power test (CPT). During post-intervention testing the HC group consumed 30–60g/h carbohydrate, whereas the LCKD group consumed water, and electrolytes. ResultsThe LCKD group experienced a significantly greater decrease in body mass (HC −0.8kg, LCKD −5.9kg; P=0.006, effect size (ES): 0.338) and percentage body fat percentage (HC −0.7%, LCKD −5.2%; P=0.008, ES: 0.346). Fasting serum beta-hydroxybutyrate (βHB) significantly increased from 0.1 at baseline to 0.5mmol/L in the LCKD group (P=0.011, ES: 0.403) in week 12. There was no significant change in performance of the 100km TT between groups (HC −1.13min·s, LCKD −4.07min·s, P=0.057, ES: 0.196). SS sprint peak power increased by 0.8 watts per kilogram bodyweight (w/kg) in the LCKD group, versus a −0.1w/kg reduction in the HC group (P=0.025, ES: 0.263). CPT peak power decreased by −0.7w/kg in the HC group, and increased by 1.4w/kg in the LCKD group (P=0.047, ES: 0.212). Fat oxidation in the LCKD group was significantly greater throughout the 100km TT. ConclusionsCompared to a HC comparison group, a 12-week period of keto-adaptation and exercise training, enhanced body composition, fat oxidation during exercise, and specific measures of performance relevant to competitive endurance athletes.

Effects of Macronutrient Distribution on Weight and Related Cardiometabolic Profile in Healthy Non-Obese Chinese: A 6-month, Randomized Controlled-Feeding Trial

BackgroundIt has been suggested that the increase in carbohydrate at the expense of fat has contributed to the obesity epidemic in North America and some European countries. However, obesity rates in China have increased rapidly in parallel with a transition from the traditional low fat, high carbohydrate diet to a diet relatively high in fat and reduced in carbohydrate. Therefore, the current study aimed to determine whether the traditional Chinese diet was likely to be more effective than a diet with higher fat and lower carbohydrate — which is consumed in most Western societies, at weight control among a non-obese healthy population in China. MethodsThe 6-month, two-center, three-arm, randomized, parallel-group, controlled-feeding trial was conducted at People's Liberation Army General Hospital in north China and Zhejiang University in south China. We recruited healthy young adults (aged 18–35years, body mass index <28) who lived in the university campus or the hospital dormitory during the whole study intervention period. They were required to eat only the foods provided, and to avoid excessive or unusual strenuous exercise during the trial. Participants were simultaneously enrolled and randomized using a computer-generated number (stratified by clinic center, age, sex, and body mass index) by data manager to one of the three isocaloric diets (1:1:1): a lower fat, higher carbohydrate diet (fat 20%, carbohydrate 66% energy); a moderate fat, moderate carbohydrate diet (fat 30%, carbohydrate 56% energy); a higher fat, lower carbohydrate diet (fat 40%, carbohydrate 46% energy). Protein provided 14% energy in all diets. We provided all food and beverages throughout the 6-month intervention. Laboratory personnel were masked to treatment allocation. Body weight was the primary outcome and measured each month. Data were primarily analyzed according to an intention-to-treat approach, supplemented with per-protocol analysis. The study was approved by the Ethics Committee at Zhejiang University. Each participant provided written informed consent. The study was registered at Clinicaltrials.gov, number NCT02355795. FindingsBetween April 30, 2016, and October 30, 2016, 307 participants were randomly assigned to the lower fat diet (n=101), the moderate fat diet (n=105) and the higher fat diet (n=101), and 245 (79.8%) participants completed the study. Reduction in body weight was significantly greater in the lower fat, higher carbohydrate group throughout the intervention (P<0.001 for the interaction between diet group and time) than in the two other groups. Weight change at 6months was −1.6kg (95% CI −1.8 to −1.4) in the lower fat, higher carbohydrate group; −1.1kg (95% CI −1.3 to −0.9) in the moderate fat, moderate carbohydrate group, and −0.9kg (95% CI −1.1 to −0.6) in the higher fat, lower carbohydrate group. Reduction in waist circumference, total cholesterol, low-density lipoprotein cholesterol and non-high-density lipoprotein cholesterol on the lower fat, higher carbohydrate group were greater than those observed on the other two diet groups. InterpretationA lower fat, relatively higher carbohydrate diet, similar in macronutrient composition to that traditionally eaten in China appears to be less likely to promote excessive weight gain and be associated with a lower cardiometabolic risk profile than a diet more typical of that eaten in Western countries in healthy non-obese Chinese. Findings from studies in European and North American populations suggesting possible benefits of carbohydrate restriction may not apply to people of other ethnicities.

Zinc Intake, Zinc Bioavailability and Plasma Zinc in Obese Adolescents with Clinical Insulin Resistance Following Low Energy Diets

Background: Zinc has a critical role in metabolism and growth. This study aims to determine the effects of low-energy diets differing in macronutrient composition on zinc intake, estimated zinc bioavailability (phytate:zinc molar ratio) and plasma zinc concentration and associations between zinc status and cardiometabolic markers in obese adolescents with clinical insulin resistance (IR). Methods: Eighty-seven obese adolescents (10-17 years, body mass index z-score 2.3 ± 0.37) with clinical IR were randomized to a low-energy diet (6.0-8.0 MJ), which was either high carbohydrate or moderate carbohydrate with increased protein. Twenty-four-hour dietary recalls were collected at 6, 9 and 12 weeks. Plasma zinc concentration and cardiometabolic markers were assessed at baseline and 12 weeks. Results: Zinc intake did not differ between the 2 diet groups (p = 0.612). The high-carbohydrate group had a higher phytate intake (894 vs. 671 mg, p = 0.018) and phytate:zinc molar ratio (9.4 vs. 7.4, p = 0.009) than the increased-protein group. Plasma zinc concentration did not change from baseline in either of the diet groups, but correlated positively with zinc intake (r = 0.235, p = 0.042) and % energy from protein (r = 0.383, p = 0.001), and inversely with % energy from carbohydrate (r = -0.296, p = 0.010). Conclusions: Low energy diets for obese adolescents at risk of diabetes may need increased protein content to optimize zinc bioavailability.

Effects of metformin and sitagliptin on glycolipid metabolism in type 2 diabetic rats on different diets.

IntroductionThe aim of the study was to investigate the effects of metformin and sitagliptin on glycolipid metabolism in type 2 diabetes after different diets.Material and methodsSeventy Male Sprague Dawley rats were fed with a high fat diet followed by streptozotocin treatment to induce type 2 diabetes. Then all rats were randomly divided into a control group, a metformin group (200 mg/kg), and a sitagliptin group (10 mg/kg). Each group was further divided into 4 groups receiving one load of high carbohydrate diet (45% glucose, 4.5 ml/kg), high fat diet (20% lipid emulsion, 4.5 ml/kg), high protein diet (20% whey protein, 10 ml/kg) or mixed meal, respectively. The caloric densities were all 33 kJ/kg. Postprandial blood glucose (P2BG), triglyceride (TG), glucagon-like peptide-1 (GLP-1), glucagon and insulin levels were measured.ResultsIn the high carbohydrate group, sitagliptin was more efficient in lowering P2BG compared with metformin (p < 0.05). In the high-fat group, metformin was more powerful in lowering TG (p < 0.05) and P2BG (p < 0.05) levels because of its improvement of insulin sensitivity. In the high protein diet group, metformin did not reduce the P2BG level (p > 0.05), although it did reduce the TG level (p < 0.05). In the mixed diet group, metformin was more efficient in lowering P2BG (p < 0.05) but had a similar effect on TG (p > 0.05) compared with sitagliptin.ConclusionsIn the type 2 diabetic model, metformin and sitagliptin have different effects on glycolipid metabolism after different diets. If it is proved in type 2 diabetic patients, then different medicines may be recommended according to different diets in order to improve glycolipid metabolism.

12. Remission of Impaired Glucose Tolerance (IGT) to Normal Glucose Tolerance (NGT) in Obese Adults with High Protein vs. High Carbohydrate Diet (90-OR)

The purpose of this study is to identify a diet that facilitates weight loss and conversion of patients with impaired glucose tolerance (IGT) to normal glucose tolerance (NGT). Specific aim was to determine if a High Protein (HP) or High Carbohydrate (HC) diet is more effective in conversion of IGT obese adults to NGT. 18 obese, pre-diabetic adults were randomized to a HP or HC diet for 6 months (mo) with all food provided. The HP diet consisted of 30% protein, 30% fat, 40% carbohydrates while the HC diet consisted of 15% protein, 30% fat, 55% carbohydrates distributed by percentage of daily kcals derived for each subject. An Oral Glucose Tolerance Test (OGTT) was performed at Baseline (BL) and 6 mo to determine IGT/NGT status. A 2 hr glucose between 140 to 199 mg/dl was considered IGT. DXA was done at BL and 6 mo. Food pick up and weight checks were weekly. Both diet groups had weight loss, improvement in insulin sensitivity determined by HOMA IR [HP (BL 4.69 ± 0.26; 6 mo 1.58 ± 0.14)], [HC (4.62 ± 0.26; 6 mo 3.15 ± 0.27)] and decrease in HbA1c [HP (BL 5.99 ± .05; 6 mo 5.53 ± .02)], [HC (BL 5.9 ± .04; 6 mo 5.69 ± .06)]. The HP diet had a 100% (9/9) conversion rate to NGT while the HC diet had a 44.4% (4/9) conversion rate. HP group had a 2.8 ± .4% increase in lean body mass and 2.5 ± 0.4% decrease in fat mass while the HC group had a 2.1 ± 1.1% and 3.5 ± 0.9 % decrease in lean and fat mass with greater overall average weight loss. Both diets resulted in improvement in glucose tolerance and insulin sensitivity but the HP diet was most effective. Our results suggest that lean body mass preservation may be more important than total weight loss in the conversion of IGT to NGT, possibly due to the high insulin sensitivity of muscle cells.

PD33-05 TUMOR-SUPPRESSIVE MICRORNA-29S-MEDIATED NOVEL MOLECULAR PATHWAYS IN RENAL CELL CARCINOMA

insulin signaling in the progression of a murine RCC model using metformin to treat hyperinsulinemia induced by a high-carbohydrate diet. METHODS: pT1-T4 tumor specimens from 99 patients with RCC were evaluated for IR expression by immunohistochemistry. Serum insulin and C-peptide levels were measured. The association between biomarker expression and serum concentration, prognostic factors, and clinical outcomes were assessed. C57BL/6 mice were randomized into four groups: low-carbohydrate diet, high-carbohydrate diet, low-carbohydrate diet þ metformin, and high-carbohydrate diet þ metformin groups. RENCA cells were injected subcutaneously. Body weight, glucose tolerance test, serum insulin level, and tumor volume were evaluated. Immunoblotting was performed to assess the insulin signaling pathway in the murine RCC model. RESULTS: The IR expression level was significantly lower in patients with tumor stage pT2-4 and with a preoperative serum Cpeptide level more than 5.14 ng/mL. High IR expression was an independent predictor of favorable progression-free survival after radical nephrectomy. In vivo progression of RENCA in the murine model was not significantly stimulated by hyperinsulinemia induced by a high-carbohydrate diet. However, in vivo progression of RENCA was significantly inhibited by metformin in both the lowand highcarbohydrate diet groups. IR expression was significantly higher in the tumors from the low-carbohydrate diet group and high-carbohydrate diet plus metformin group than that from the high-carbohydrate diet group. CONCLUSIONS: IR expression in RCC was inversely associated with cancer progression and serum insulin levels in both clinical and murine models. The anticancer effect of metformin in the murine RCC model might be derived from the direct effect of the agent on cancer cells rather than the effect of the lower insulin level. The lower expression of IR in the tumor from patients with a poor outcome might be the result of a higher serum insulin level, which is not strong cause of cancer progression.

Postnatal exposure to a high-carbohydrate diet interferes epigenetically with thyroid hormone receptor induction of the adult male rat skeletal muscle glucose transporter isoform 4 expression

Early life nutritional intervention causes adult-onset insulin resistance and obesity in rats. Thyroid hormone receptor (TR), in turn, transcriptionally enhances skeletal muscle Glut4 expression. We tested the hypothesis that reduced circulating thyroid-stimulating hormone and T4 concentrations encountered in postnatal (PN4–PN24) high-carbohydrate (HC) milk formula-fed versus the mother-fed controls (MF) would epigenetically interfere with TR induction of adult (100days) male rat skeletal muscle Glut4 expression, thereby providing a molecular mechanism mediating insulin resistance. We observed increased DNA methylation of the CpG island with enhanced recruitment of Dnmt3a, Dnmt3b and MeCP2 in the glut4 promoter region along with reduced acetylation of histone (H)2A.Z and H4 particularly at the H4.lysine (K)16 residue, which was predominantly mediated by histone deacetylase 4 (HDAC4). This was followed by enhanced recruitment of heterochromatin protein 1β to the glut4 promoter with increased Suv39H1 methylase concentrations. These changes reduced TR binding of the T3 response element of the glut4 gene (TREs; −473 to −450bp) detected qualitatively in vivo (electromobility shift assay) and quantified ex vivo (chromatin immunoprecipitation). In addition, the recruitment of steroid receptor coactivator and CREB-binding protein to the glut4 promoter–protein complex was reduced. Co-immunoprecipitation experiments confirmed the interaction between TR and CBP to be reduced and HDAC4 to be enhanced in HC versus MF groups. These molecular changes were associated with diminished skeletal muscle Glut4 mRNA and protein concentrations. We conclude that early postnatal exposure to HC diet epigenetically reduced TR induction of adult male skeletal muscle Glut4 expression, uncovering novel molecular mechanisms contributing to adult insulin resistance and obesity.

Effect of Diet Intake Imbalance in Hepatocellular Carcinoma Progression

Incidence of hepatocellular carcinoma (HCC) has increased sharply in the last 10 years, with an especially high incidence in Egypt. This study was conducted to evaluate the impact of unbalanced diets on liver tumor through investigation of some biochemical mediators/pathways implicated in the pathogenesis of HCC. Male albino mice were divided into two major groups: Control group and Hepatocellular carcinoma (HCC) group; each group was further divided into four subgroups according to received diet: high fat (HF), low fat (LF), high carbohydrate (HC), and low carbohydrate (LC) groups. The results indicated that induction of HCC in mice showed marked body weight loss. Liver sections of HCC groups showed malignant giant cells and strong expression of p53. HCC mice groups kept on HF and LC diets showed the lowest survival rate, a significant increase in glucose-6-phosphate dehydrogenase (G6PDH), aldolase, and citrate synthase activities, a significant increase in serum E-cadherin as well as a significant decrease in insulin-like growth factor-1 (IGF-1) compared with LF diet. These results suggest that the molecular pathogenesis of HCC in mice correlates reduction of serum IGF-1 and elevated serum E-cadherin accompanied by reprogrammed metabolic profile shifted towards increased glycolysis and lipogenesis. These pathogenic changes were enhanced by over-consumption of carbohydrates, fats, and proteins, whereas dietary fat restriction could have a protective/ameliorative effect against the incidence of HCC.

Duplicated CCAAT/enhancer-binding protein β (C/EBPβ) gene: Transcription and methylation changes in response to dietary betaine in Landes goose liver

The CCAAT/enhancer-binding protein β gene (C/EBPβ) is one of the key regulating factors of lipid metabolic balance in the liver. To better understand how C/EBPβ affects lipid accumulation in the Landes goose liver, its DNA was cloned. The goose C/EBPβ DNA sequence (2,075 bp) contains a 984-bp open reading frame and part of the 5'-flanking region, and shares 96.66 and 62.07% similarity with the chicken and human sequences at the amino acid level, respectively. Tissue expression profiling showed that the relative expression level was high in the liver and adipose tissue. To understand the effect of betaine on C/EBPβ in goose liver, the relative expression levels of C/EBPβ were detected under different treatments. Compared with the control group, C/EBPβ expression increased in the high-carbohydrate group (P < 0.01) and decreased in the betaine treatment group (P > 0.05). Using bisulfite sequencing PCR, the gene methylation status was analyzed among the different treatment groups. None of the 54 CpG sites in the promoter region or the 28 CpG sites in the structural domain of the coding region showed any significantly different methylation patterns among the groups. Taken together, the results showed that betaine decreased the goose C/EBPβ gene expression, but did not directly regulate its methylation. The data may form the basis for further investigation of the mechanisms of the effect of C/EBPβ on the regulation of lipometabolism in the goose liver and the effect of betaine on lipid metabolic genes at the molecular level.

Blood Pressure Decreases More after High-Carbohydrate Meals Than after High-Protein Meals in Overweight Adults with Elevated Blood Pressure, but There Is No Difference after 4 Weeks of Consuming a Carbohydrate-Rich or Protein-Rich Diet

The replacement of dietary carbohydrates with proteins can lower blood pressure (BP), but the mechanisms remain unclear. This randomized, double-blind, parallel-group study aimed to compare 12-h postprandial sympathetic and hemodynamic responses after high-protein (HP) meals and high-carbohydrate (HC) meals. Fifty-two men and women with untreated elevated BP were tested on d 1 and after 4 wk of supplementation [3 × 20 g protein (HP) or maltodextrin (HC) per day]. No between-group differences were found in postprandial plasma norepinephrine on d 1 and at wk 4. On d 1, postprandial mean arterial pressure (MAP) decreased more in the HC group than in the HP group (P = 0.002). This difference was not present at 4 wk, because the postprandial decline in MAP tended to become larger in the HP group after 4 wk of supplementation (P = 0.07). On both test days, postprandial total peripheral resistance tended to decrease more in the HC group (P < 0.08). After 4 wk of supplementation, cardiac output tended to increase more in the HC group (P = 0.08). In conclusion, ingestion of an HP diet induced a smaller decrease in BP on d 1 than did ingestion of an HC diet. This difference disappeared after 4 wk due to a more pronounced decrease in BP in the HP group after 4 wk than on d 1. These findings cannot explain the BP-lowering effect ascribed to dietary proteins.

A cafeteria diet modifies the response to chronic variable stress in rats

Stress is known to lead to metabolic and behavioral changes. To study the possible relationships between stress and dietary intake, male Sprague-Dawley rats were fed one of three diets for 6 weeks: high carbohydrate (HC), high fat (HF), or “Cafeteria” (CAF) (Standard HC plus a choice of highly palatable cafeteria foods: chocolate, biscuits, and peanut butter). After the first 3 weeks, half of the animals from each group (experimental groups) were stressed daily using a chronic variable stress (CVS) paradigm, while the other half of the animals (control groups) were kept undisturbed. Rats were sacrificed at the end of the 6-week period. The effects of stress and dietary intake on animal adiposity, serum lipids, and corticosterone were analyzed. Results showed that both chronic stress and CAF diet resulted in elevated total cholesterol, increased low-density lipoprotein (LDL), and lower high-density lipoprotein (HDL). In addition, increases in body weight, food intake, and intra-abdominal fat were observed in the CAF group compared with the other dietary groups. In addition, there was a significant interaction between stress and diet on serum corticosterone levels, which manifest as an increase in corticosterone levels in stressed rats relative to non-stressed controls in the HC and HF groups but not in the CAF group. These results show that a highly palatable diet, offering a choice of food items, is associated with a reduction in the response to CVS and could validate a stressor-induced preference for comfort food that in turn could increase body weight.

Modulation of cholesterol‐induced hepatic steatosis by macronutrient manipulation in guinea pigs

We sought to examine the impact of high cholesterol (HChol) on the development of non‐alcoholic fatty liver disease in male guinea pigs and evaluated whether a low‐carbohydrate diet (LCD) could effectively improve hepatic morphology and liver function following a HChol diet. Forty guinea pigs were randomly assigned to consume a HChol (0.25%) (n = 30) or a low‐cholesterol (LChol) diet (0.04%) (n = 10). After 6 wk 20 animals were sacrificed (10 LChol and 10 HChol) and plasma and livers were collected for analysis. Plasma total cholesterol (TC) (290.2 ± 62.27 vs 49.5 ± 11.81 mg/dL), LDL, and HDL were higher in the HChol group (P&lt;0.01). Liver enzymes ALT and AST were also higher in the HChol group and the liver to body weight ratio was higher in the HChol group (P&lt;0.01). Histologically, HChol livers displayed extensive hepatic steatosis while this was not observed in LChol livers. The remainder of the animals were randomly assigned (n=10/group) either to a LCD or high‐carbohydrate (HCD) diet. After 6 wk, no differences in plasma TC or LDL were observed, however AST was higher in guinea pigs fed the HCD and was significantly correlated with plasma TC (r = 0.884, P&lt; 0.05). Additionally, the ratio of liver weight to body weight was positively correlated with plasma ALT only in the HCD group. These results indicate that HChol successfully induces hepatic steatosis and LCD fed guinea pigs appear to have improved liver function relative to HCD.

Ingestion of Carbohydrate-Rich Supplements during Gestation Programs Insulin and Leptin Resistance but not Body Weight Gain in Adult Rat Offspring

Prenatal nutritional conditions can predispose to development of obesity and metabolic syndrome in adulthood. Gestation with its important modifications in hormonal status is a period of changes in normal feeding habits with pulses of consumption or avoidance of certain categories of food. We tried to mimic in an animal model some changes in food consumption patterns observed in pregnant women. For this purpose, Long–Evans female rats were fed during the dark period, their usual pre-gestational food quantity, and were allowed to complete their daily intake with either a restricted control (Cr), high-fat (HF), or high-carbohydrate (HC) diet available ad libitum during the light period. Dams fed a control diet ad libitum (Ca) served as controls. Body weight and composition, food intake, and metabolic hormones (insulin, leptin) were recorded in male offspring until 20 weeks after birth. Cr and HC females ate less than Ca females (−16%; p < 0.001) and their offspring presented a weight deficit from birth until 6 (HC group) and 10 (Cr group) weeks of age (p < 0.05 or less). Plasma leptin corresponded to low body weight in Cr offspring, but was increased in HC offspring that in addition, had increased plasma insulin, blood glucose, and subcutaneous adipose tissue mass. HF dams ate more than Ca dams (+13%; p < 0.001), but plasma leptin and insulin were similar in their offspring. Hypothalamic Ob-Rb expression was increased in Cr, HC, and HF offspring (+33–100% vs Ca; p < 0.05 or less). HC supplement ingestion during gestation therefore leads to insulin and leptin resistance in adult offspring independently of lower birth weight. These hormonal changes characterize obesity-prone animals. We therefore suggest that attention should be paid to the carbohydrate snacking and overall carbohydrate content in the diet during the last weeks (or months) preceding delivery to limit development of later metabolic disorders in offspring.

A Carbohydrate-Restricted Diet during Resistance Training Promotes More Favorable Changes in Body Composition and Markers of Health in Obese Women with and without Insulin Resistance

Objective: To determine whether sedentary obese women with elevated levels of homeostatic model assessment (HOMA) insulin resistance (ie, > 3.5) experience greater benefits from an exercise + higher-carbohydrate (HC) or carbohydrate-restricted weight loss program than women with lower HOMA levels. Methods: 221 women (age, 46.5 ± 12 years; body weight, 90.3 ± 16 kg; body mass index, 33.8 ± 5 kg/m2) participated in a 10-week supervised exercise and weight loss program. The fitness program involved 30 minutes of circuit-style resistance training 3 days per week. Subjects were prescribed low-fat (30%) isoenergetic diets that consisted of 1200 kcals per day for 1 week (phase 1) and 1600 kcals per day for 9 weeks (phase 2) with HC or higher protein (HP). Fasting blood samples, body composition, anthropometry, resting energy expenditure, and fitness measurements were obtained at 0 and 10 weeks. Subjects were retrospectively stratified into lower (LH) or higher (HH) than 3.5 HOMA groups. Data were analyzed by multivariate analysis of variance with repeated measures and are presented as mean ± standard deviation changes from baseline. Results: Baseline HOMA levels in the LH group were significantly lower than those in the HH group (LH, 0.6 ± 0.7; HH, 6.3 ± 3.4; P = 0.001). Diet and training significantly decreased body weight (−3.5 ± 3 kg), fat mass (−2.7 ± 3 kg), blood glucose (−3%), total cholesterol (−4.5%), low-density lipoproteins (−5%), triglycerides (−5.9%), systolic blood pressure (−2.6%), and waist circumference (−3.7%), while increasing peak aerobic capacity (7.3%). Subjects in the HP group experienced greater weight loss (−4.4 ± 3.6 kg vs −2.6 ± 2.9 kg), fat loss (−3.4 ± 2.7 kg vs −1.7 ± 2.0 kg), reductions in serum glucose (3% vs 2%), and decreases in serum leptin levels (−30.8% vs −10.8%) than those in the HC group. Participants in the HH (−14.1%) and HP-HH (−21.6%) groups observed the greatest reduction in serum blood glucose. Conclusion: A carbohydrate-restricted diet promoted more favorable changes in weight loss, fat loss, and markers of health in obese women who initiated an exercise program compared with a diet higher in carbohydrate. Additionally, obese women who initiated training and dieting with higher HOMA levels experienced greater reductions in blood glucose following an HP diet.

Effects of Intermittent Dieting During Resistance Training in Women IV: Quality of Life

Dieting has been reported to reduce resting energy expenditure thereby increasing the prevalence of weight gain after weight loss. Intermittent dieting during a weight loss and exercise program may help minimize these adverse effects. PURPOSE: To examine the efficacy of diet cycling with varying macronutrient diet compositions during an exercise and weight loss program on weight loss, markers of health, and fitness. METHODS: 43 overweight and sedentary women (35±8 yr; 89±18 kg; 43±4% fat, 33±6 kg/m2) were assigned to a high carbohydrate (HC, n=23) or high protein (HP, n=20) diet group. During the first 30-days, subjects consumed 1,200 kcals/d for 1-wk followed by ingesting 1,500 kcals/d for 3-wks. Subjects then followed a 2,200 kcals/d maintenance diet for 4-wks before repeating the 30-day diet. Diets were 45:30:25% or 30:45:25% carbohydrate, protein and fat, respectively, for the HC and HP groups, respectively. Subjects also participated in the Curves™ circuit training program 3-d/wk and walked briskly for 30-min 3-d/wk. The SF-36 Quality of Life (QOL) long-version psychosocial inventory was obtained at each testing interval. Data were analyzed by MANOVA with repeated measures and are presented as percent change from baseline after 1, 2, 3, 4, and 5 months respectively. RESULTS: Training and dieting improved Physical Functioning (6.4, 8.3, 9.5, 10.7, 9.5%, p<0.001); Role-Physical (9.8, 9.5, 11.0, 6.9, 10.1%, p=0.05); Role-Emotional (4.7, 7.9, 11.2, 10.4, 10.8%, p=0.001); Vitality (11.4, 10.5, 11.0, 10.5, 10.5%, p=0.04); Mental Health (10.8, 11.7, 11.9, 12.6, 10.0%, p=0.004); Bodily Pain (5.1, 5.2, 5.8, 5.9, 8.1%, p=0.014); and, General Health (6.9, 8.9, 7.6, 7.1, 7.4%, p=0.04). However, no significant differences were seen in Social Functioning (1.8, -0.6, -3.0, -3.0, -1.2%, p=0.31). In addition, no significant differences were observed between diets on QOL when diets were 45:30:25% or 30:45:25% carbohydrate, protein, and fat, respectively. CONCLUSION: Short-term diet cycling during a weight loss and exercise program improves markers of QOL. Diet had no influence when both diets were greater than 30% protein. Supported by Curves International, Waco, TX

Effects of Intermittent Dieting During Resistance Training In Women III: Fitness

Dieting has been reported to reduce resting energy expenditure, thereby increasing the prevalence of weight gain after weight loss. Intermittent dieting during a weight loss and exercise program may help minimize these adverse effects. PURPOSE: To examine the efficacy of diet cycling with varying macronutrient diet compositions during an exercise and weight loss program on selected markers of health and fitness. METHODS: 38 overweight, sedentary women (35±8 yr; 85±19 kg; 43±4% fat, 33±6 kg/m2) were assigned to a high carbohydrate (HC: n=20) or high protein (HP: n=18) diet group. During the first 30-days, subjects consumed 1,200 kcal/d for 1-wk, followed by 1,500 kcal/d for 3-wks. Subjects then followed a 2,200 kcal/d maintenance diet (4-wks) before repeating the 30-day cycle. Diets were 45:30:25% or 30:45:25% carbohydrate, protein and fat, respectively, for the HC and HP groups. Subjects also participated in the Curves™ circuit training program (3-d/wk), and walked briskly for 30-min (3-d/wk). Body composition, resting heart rate, blood pressure, peak VO2, GXT max time, 1RM strength, and muscle endurance tests were obtained at 0, 3, and 6 months. Data were analyzed by MANOVA with repeated measures, and are presented as means ± SD changes from baseline after 3 and 6 months, respectively. RESULTS: Training and dieting decreased total body mass (-4.1±3.4, -5.2±4.9 kg, p=0.001), fat mass (-2.7±2.1, -3.5±3.4 kg, p=0.001), lean mass (-1.2±1.9, -1.2±1.9 kg, p=0.001), SBP (-3.6±10, -2.9±10%, p=0.08), DBP (-1.7±14, -3.5±14%, p=0.14); and, increased peak VO2 (9.7±17, 11.7±19%, p=0.001), time to peak VO2 (39.7±49, 45.0±65 s, p=0.001), leg press 1RM (13.8±24, 14.5±23%, p=0.002), and bench press 1RM (6.7±10, 5.1±12%, p=0.03). The HP diet was more effective in lowering resting HR compared to the HC diet (p=0.03). Neither upper nor lower muscular endurance was significantly improved. CONCLUSION: Short-term diet cycling during a weight loss and exercise program may be an effective way to improve body composition, promote favorable hemodynamic changes, and improve VO2, as well as upper and lower body strength. Supported by Curves International, Waco TX.