The Combined Effects of Exercise,Diet, and a Multi-Ingredient Dietary Supplement on Body Composition and Adipokine Changes in Overweight Adults

Background: Very few weight and fat loss supplements undergo finished-product research to examine efficacy. The purpose of this study was to determine the effects of an 8-week diet and exercise program on body composition, hip and waist girth, and adipokines and evaluate whether a dietary supplement containing raspberry ketone, capsaicin, caffeine, garlic, and Citrus aurantium enhanced outcomes.

Methods: Overweight men and women completed this randomized, placebo-controlled, double-blind study. Participants consumed 4 capsules/d of supplement (EXP; n = 18) or placebo (PLA; n = 18). Participants underwent 8 weeks of daily supplementation, calorie restriction (500 kcal < RMR [resting metabolic rate] × 1.2), and supervised progressive exercise training 3 times a week. Body composition, girth, and adipokines were assessed at baseline and postintervention (T1 and T2).

Results: Significant decreases in weight (?2.6 ± 0.57 kg, p < 0.001), fat mass (?1.8 ± 0.20 kg; p < 0.001), and percentage body fat (?3.7% ± 0.29%, p < 0.001) and a significant increase in lean body mass (LBM; 1.5 ± 0.26 kg; p < 0.001) were seen from T1 to T2 in both groups. For men, only those in the EXP group increased LBM from T1 to T2 (1.3 ± 0.38 kg; p < 0.05). Hip girth was also reduced, with the women in the EXP group (?10.7 ± 2.15 cm, p < 0.001) having a greater reduction. There was a time by group interaction, with significant decreases in leptin (p < 0.001) and significant increases in adiponectin (p < 0.05) in the EXP group.

Conclusions: Significant improvements in adipokines and leptin support the utility of exercise, diet, and fat loss for impacting inflammatory biomarkers. The improvement in adiponectin with EXP may suggest a unique health mechanism.     

The Effect of a Vegetarian vs Conventional Hypocaloric Diabetic Diet on Thigh Adipose Tissue Distribution in Subjects with Type 2 Diabetes: A Randomized Study

Objective: The aim of our study was to compare the effects of a vegetarian and a conventional diet on thigh adipose tissue distribution in subjects with type 2 diabetes (T2D).

Methods: Seventy-four subjects with T2D were randomly assigned to either follow a vegetarian diet (V, n = 37) or a control group who followed an isocaloric conventional anti-diabetic diet (C, n = 37). Both diets were calorie restricted (?500 kcal/day). To measure insulin sensitivity, the hyperinsulinemic (1 mU.kg^?1.min^?1) isoglycemic clamp was conducted. β-Cell function was assessed using a mathematical model after a test meal. Magnetic resonance imaging of the thigh was performed. All subjects were examined at 0, 3, and 6 months. Statistical analyses were performed using repeated measures analysis of variance and a multivariate regression model.

Results: Greater reduction was observed in total leg area in V (?13.6 cm² [95% confidence interval [CI], ?14.2 to ?12.9] in V vs ?9.9 cm² [95% CI, ?10.6 to ?9.2] in C; Gxt p < 0.001). The reduction in subcutaneous fat was comparable in response to both diets (Gxt, p = 0.64). Subfascial fat was reduced only in response to a vegetarian diet (?0.82 [95% CI, ?1.13 to ?0.55] cm² in V vs ?0.44 [95% CI, ?0.78 to +0.02] cm² in C; Gxt, p = 0.04). The reduction in intramuscular fat tended to be greater in response to a vegetarian diet (?1.78 [95% CI, ?2.26 to ?1.27] cm² in V vs ?0.57 [95% CI, ?1.06 to ?0.09] cm² in C; Gxt, p = 0.12). Changes in subcutaneous and subfascial fat correlated with changes in glycated hemoglobin (HbA1c), fasting plasma glucose, and β-cell insulin sensitivity. After adjustment for changes in body mass index (BMI), correlations remained significant for changes in fasting plasma glucose and β-cell insulin sensitivity and with changes in triglycerides.

Conclusions: Our data indicate the importance of both subcutaneous and subfascial fat in relationship to glucose and lipid metabolism.

Abbreviations: BMI , body mass index; C , control group; FPG , fasting plasma glucose; Gxt , interaction between group and time; HbA1c , glycated hemoglobin; MCR , metabolic clearance rate of glucose; OPLS , orthogonal projections to latent structure; T2D , type 2 diabetes; V , vegetarian group     

Short-Term Mediterranean Diet Improves Endurance Exercise Performance: A Randomized-Sequence Crossover Trial

Abstract

Objective: Healthful dietary patterns have constituents that are known to improve exercise performance, such as antioxidants, nitrates, and alkalizing effects. However, ergogenic effects of such diets have not been evaluated. We hypothesized that a short-term Mediterranean diet results in better exercise performance, as compared to a typical Western diet.

Methods: Eleven recreationally active women (n?=?7) and men (n?=?4) (body mass index, 24.6?±?3.2?kg/m²; age 28?±?3?years) were studied in a randomized-sequence crossover study, in which they underwent exercise performance testing on one occasion after 4?days of a Mediterranean diet and on another occasion after 4?days of a Western diet. A 9- to 16-day washout period separated the two trials. Endurance exercise performance was evaluated with a 5-km treadmill time trial. Anaerobic exercise performance tests included a Wingate cycle test, a vertical jump test, and hand grip dynamometry.

Results: Five-kilometer run time was 6%?±?3% shorter (faster) in the Mediterranean diet trial than in the Western diet trial (27.09?±?3.55 vs 28.59?±?3.21?minutes; p?=?0.030) despite similar heart rates (160?±?5 vs 160?±?4 beats/min; p?=?0.941) and ratings of perceived exertion (14.6?±?0.5 vs 15.0?±?0.5; p?=?0.356). No differences between the diet conditions were observed for anaerobic exercise tests, including peak and mean power from the Wingate test (both p?≥?0.05), the vertical jump test (p?=?0.19), and the hand grip strength test (p?=?0.69).

Conclusions: Our findings extend existing evidence of the health benefits of the Mediterranean diet by showing that this diet is also effective for improving endurance exercise performance in as little as 4?days. Further studies are warranted to determine whether a longer-term Mediterranean diet provides greater benefits and whether it might also be beneficial for anaerobic exercise performance and muscle strength and power.     

Influence of Energy Balance and Glycemic Index on Metabolic Endotoxemia in Healthy Men

Objective: Overfeeding with a high-fat and/or high-carbohydrate (CHO) diet is known to increase plasma concentrations of endotoxin (lipopolysaccharide [LPS]) that may lead to metabolic disturbances like insulin resistance. The impact of CHO quality (i.e., the glycemic index [GI]) independent of fat intake on metabolic endotoxemia remains unclear. In the present study, the effects of changes in energy balance and GI on plasma endotoxin were studied.

Methods: Fifteen healthy young men overconsumed diets containing 65% CHO and 20% fat for 1 week (OF; +50% of energy requirement) followed by 3 weeks of caloric restriction (CR; ?50% of energy requirement) and were then randomized to 2 weeks hypercaloric refeeding (RF, +50% of energy requirement) with either a low- or high-GI (40 vs 74) diet.

Results: During OF, subjects gained 1.9 ± 0.7 kg body weight (+0.6 ± 0.8% fat mass) followed by a weight loss of 6.1 ± 0.8 kg (?2.0 ± 0.6% fat mass) and weight regain of 4.0 ± 0.6 kg (0.9 ± 0.8% fat mass). Fasting insulin and homeostasis model assessment–insulin resistance (HOMA_IR) increased with OF and RF and decreased with CR, Matsuda_ISI decreased by 37% after RF (all p < 0.05). Endotoxin significantly increased by 30.8% with OF and by 24.7% with RF (both p < 0.05), whereas CR normalized endotoxin levels. No difference in endotoxin levels was observed between refeeding a hypercaloric high- or low-GI diet. Changes in endotoxin levels with RF were not related to changes in insulin sensitivity.

Conclusion: A hypercaloric diet (OF and RF) increased plasma endotoxin irrespective of GI, whereas a negative energy balance did not reduce endotoxemia. Impaired insulin sensitivity with hypercaloric refeeding on a high-GI diet was not explained by metabolic endotoxemia.     

The Impact of a High-Carbohydrate/Low Fat vs. Low-Carbohydrate Diet on Performance and Body Composition in Physically Active Adults: A Cross-Over Controlled Trial

Background: Recently, high-carbohydrate or low-carbohydrate (HC/LC) diets have gained substantial popularity, speculated to improve physical performance in athletes; however, the effects of short-term changes of the aforementioned nutritional interventions remain largely unclear. Methods: The present study investigated the impact of a three-week period of HC/low-fat (HC) diet followed by a three-week wash-out-phase and subsequent LC diet on the parameters of physical capacity assessed via cardiopulmonary exercise testing, body composition via bioimpedance analysis and blood profiles, which were assessed after each of the respective diet periods. Twenty-four physically active adults (14 females, age 25.8 ± 3.7 years, body mass index 22.1 ± 2.2 kg/m²), of which six participants served as a control group, were enrolled in the study. Results: After three weeks of each diet, VO_2peak was comparable following both interventions (46.8 ± 6.7 (HC) vs. 47.2 ± 6.7 mL/kg/min (LC; p = 0.58)) while a significantly higher peak performance (251 ± 43 W (HC) vs. 240 ± 45 W (LC); (p = 0.0001), longer time to exhaustion (14.5 ± 2.4 min (HC) vs. 14.1 ± 2.4 min (LC); p = 0.002) and greater Watt/kg performance (4.1 ± 0.5 W/kg (HC) vs. 3.9 ± 0.5 W/kg (LC); p = 0.003) was demonstrated after the HC diet. In both trial arms, a significant reduction in body mass (65.2 ± 11.2 to 63.8 ± 11.8 kg (HC) vs. 64.8 ± 11.6 to 63.5 ± 11.3 kg (LC); both p < 0.0001) and fat mass (22.7% to 21.2%; (HC) vs. 22.3% to 20.6% (LC); both p < 0.0001) but not in lean body mass or skeletal muscle mass was shown when compared to baseline. Resting metabolic rate was not different within both groups (p > 0.05). Total cholesterol and LDL-cholesterol significantly decreased after the HC diet (97.9 ± 33.6 mg/dL at baseline to 78.2 ± 23.5 mg/dL; p = 0.02) while triglycerides significantly increased (76 ± 38 mg/dL at baseline to 104 ± 44 mg/dL; p = 0.005). Conclusion: A short-term HC and LC diet showed improvements in various performance parameters in favor of the HC diet. Some parameters of body composition significantly changed during both diets. The HC diet led to a significant reduction in total and LDL-cholesterol while triglycerides significantly increased.     

Ethnic differences in the cardiac responses to aerobic exercise

Background: Cardiovascular disease disproportionately affects North American Indigenous populations. Ethnic differences in cardiac responses to exercise are known, though Indigenous populations response is unknown. To evaluate cardiac responses to aerobic exercise among Canadian Indigenous and European adults.

Methods: Indigenous (N?=?12, 4 females, 1 male incomplete) and European (N?=?12, all completed) Canadian age and sex-matched adults 19–40 years and free of cardiovascular disease or diabetes completed a cycle ergometer maximal aerobic power test and 30?min at 60% maximal aerobic capacity on two separate days. Echocardiographic assessments preceded and immediately followed exercise.

Results: Responses to maximal exercise were similar among ethnicities including decreases in stroke volume index, cardiac output index and ejection fraction, and increases in arterial-ventricular coupling. However, following submaximal exercise, only Indigenous adults demonstrated reductions in end systolic volume, end diastolic volume (154.8?±?40.6?mL to 136.5?±?33.0?mL, p?=?0.01, vs. 149.4?±?22.4?mL to 147.1?±?27.0?mL; p?=?0.81), stroke volume index (44.9?±?8.7?mL?m^?2 to 38.0?±?6.5?mL?m^?2, p?=?0.002, vs. 46.4?±?7.1?mL?m^?2 to 44.0?±?6.5?mL?m^?2; p?=?0.28) and arterial compliance.

Conclusion: Indigenous and European adults demonstrated similar cardiac responses to maximal exercise, though only Indigenous adults demonstrated cardiac responses to submaximal exercise.     

Pistachio Nuts Reduce Triglycerides and Body Weight by Comparison to Refined Carbohydrate Snack in Obese Subjects on a 12-Week Weight Loss Program

Objective: There is a widely held view that, due to high fat content, snacking on nuts will lead to weight gain, ultimately causing unhealthy changes in lipid profiles. This study is designed to study the effects of pistachio snack consumption on body weight and lipid levels in obese participants under real-world conditions.

Methods: Participants were randomly assigned to consume 1 of 2 isocaloric weight reduction diets for 12 weeks, with each providing 500 cal per day less than resting metabolic rate. Each diet included an afternoon snack of either 53 g (240 cal) of salted pistachios (n = 31) or 56 g of salted pretzels (220 cal; n = 28).

Results: Both groups lost weight during the 12-week study (time trend, p < 0.001), but there were significant differences in the changes in body mass index between the pretzel and pistachio groups (pistachio, 30.1 ± 0.4 to 28.8 ± 0.4 vs. pretzel, 30.9 ± 0.4 to 30.3 ± 0.5). At 6 and 12 weeks, triglycerides were significantly lower in the pistachio group compared with the pretzel group (88.04 ± 9.80 mg/dL vs. 144.56 ± 18.86 mg/dL, p = 0.01 at 6 weeks and 88.10 ± 6.78 mg/dL vs. 132.15 ± 16.76 mg/dL, p = 0.02 at 12 weeks), and there was a time trend difference between the 2 groups over the 12 weeks (p < 0.01). There were no significant differences in total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, insulin, or glucose between the 2 groups.

Conclusion: Pistachios can be consumed as a portion-controlled snack for individuals restricting calories to lose weight without concern that pistachios will cause weight gain. By comparison to refined carbohydrate snacks such as pretzels, pistachios may have beneficial effects on triglycerides as well.     

Effects of Hydrolyzed Whey versus Other Whey Protein Supplements on the Physiological Response to 8 Weeks of Resistance Exercise in College-Aged Males

Objective: The objective of this study was to compare the chronic effects of different whey protein forms on body composition and performance when supplemented with resistance training.

Methods: Resistance-trained men (N = 56, 21.4 ± 0.4 years, 79.5 ± 1.0 kg) participated in an 8-week resistance training regimen (2 upper-body sessions and 2 lower-body sessions per week) and received one of 4 double-blinded treatments: 30 g/serving carbohydrate placebo (PLA) or 30 g/serving protein from either (a) 80% whey protein concentrate (WPC), (b) high-lactoferrin-containing WPC (WPC-L), or (c) extensively hydrolyzed WPC (WPH). All subjects consumed 2 servings of treatment per day; specifically, once immediately before and after training and between meals on nontraining days. Blood collection, one repetition maximum (1RM) testing for bench press and hack squat, and body composition assessment using dual-energy x-ray absorptiometry (DXA) occurred prior to training and 48 hours following the last training session.

Results: Total body skeletal muscle mass increased in all groups (p < 0.0125). There were similar between-group increases in upper-body (4%–7%, analysis of covariance [ANCOVA] interaction p = 0.73) and lower-body (24%–35%, ANCOVA interaction p = 0.85) 1RM strength following the intervention. Remarkably, WPH reduced fat mass (?6%), which was significantly different from PLA (+4.4%, p < 0.0125). No time or between-group differences were present for serum markers of health, metabolism, or muscle damage, with the exception of blood urea nitrogen being significantly lower for WPH than WPC (p < 0.05) following the intervention.

Conclusions: WPH may augment fat loss but did not provide any other advantages when used in combination with resistance training. More mechanistic research is needed to examine how WPH affects adipose tissue physiology.     

Fasting Lipoprotein and Postprandial Triacylglycerol Responses to a Low-Carbohydrate Diet Supplemented with n-3 Fatty Acids

Background: The effects of a prolonged low-carbohydrate diet rich in n-3 fatty acids on blood lipid profiles have not been addressed in the scientific literature.

Objective: This study examined the effects of an eight-week ketogenic diet rich in n-3 fatty acids on fasting serum lipoproteins and postprandial triacylglycerol (TG) responses.

Design: Ten men consumed a low-carbohydrate diet rich in monounsaturated fat (MUFA) and supplemented with n-3 fatty acids for eight weeks. Fasting blood samples were collected before and after one week of habitual diet and on two consecutive days after 2, 4, 6 and 8 weeks of the intervention diet. Postprandial TG responses to a fat-rich test meal were measured prior to and after the intervention diet.

Results: Compared to the habitual diet, subjects consumed significantly (p ≤ 0.05) greater quantities of protein, fat, MUFA and n-3 fatty acids and significantly less total energy, carbohydrate and dietary fiber. Body weight significantly declined over the experimental period (?4.2 ± 2.7 kg). Compared to baseline, fasting total cholesterol, LDL cholesterol and HDL cholesterol were not significantly different after the intervention diet (+1.5%, +9.7% and +10.0%, respectively). Fasting TG were significantly reduced after the intervention diet (?55%). There was a significant reduction in peak postprandial TG (?42%) and TG area under the curve (?48%) after the intervention diet.

Conclusions: A hypocaloric low-carbohydrate diet rich in MUFA and supplemented with n-3 fatty acids significantly reduced postabsorptive and postprandial TG in men that were not hypertriglyceridemic as a group before the diet. This may be viewed as a clinically significant positive adaptation in terms of cardiovascular risk status. However, transient increases in total cholesterol and LDL cholesterol were also evident and should be examined further in regard to which particular subfractions are elevated.     

Weight Loss Favorably Modifies Anthropometrics and Reverses the Metabolic Syndrome in Premenopausal Women

Objective: To determine the effects of a weight loss program, including dietary modifications, increased physical activity and dietary supplement (L-carnitine or placebo) on anthropometrics, leptin, insulin, the metabolic syndrome (MS) and insulin resistance in overweight /obese premenopausal women.

Methods: Participants consumed a hypocaloric diet; 30% protein, 30% fat and 40% carbohydrate in addition to increasing number of steps/day. Carnitine supplementation followed a randomized double blind protocol. Protocol lasted for 10 weeks. Seventy subjects (35 in the control and 35 in the carnitine group) completed the intervention. Anthropometrics, plasma insulin and leptin concentrations and body composition were measured. The number of subjects with the MetSyn and insulin resistance, were assessed at baseline and post-intervention.

Results: Because there were no significant differences between the carnitine and the placebo groups for all measured parameters, participants were grouped together for all analysis. Subjects decreased total energy (?26.6%, p < 0.01) and energy from carbohydrate (?17.3%, p < 0.01) and increased energy from protein by 67% (p < 0.01) and number of steps/day (42.6%, p < 0.01). Body weight (?4.6%, p < 0.001), body mass index (?4.5%, p < 0.01), waist circumference (?6.5%, p < 0.01), total fat mass (?1.7%, p < 0.01), trunk fat mass (?2.0%, p < 0.01), insulin (? 17.9%, p < 0.01) and leptin (?5.9%, p < 0.05) decreased after the intervention. Ten of 19 participants with insulin resistance became insulin sensitive and 7 of 8 participants with the MetSyn no longer had the syndrome after the intervention.

Conclusion: Moderate increases in physical activity and a hypocaloric/high protein diet resulted in multiple beneficial effects on body anthropometrics and insulin sensitivity. Realistic dietary and physical activity goals must be the focus of intervention strategies for overweight and obese individuals.     

Association of Calcium Intake and Adiposity in Postmenopausal Women

Objective: The purpose of this study was to examine the relationship between calcium intake and 1) body composition and 2) body fat distribution in postmenopausal women.

Methods: Archived data from a previous study including forty-nine Caucasian women, aged 51–73 and at least three years postmenopausal, were used for analysis. Data included medical and diet history from a questionnaire, average nutrient intake from computerized analysis of a 3-day diet record, anthropometric measures including height, weight, body mass index (BMI), waist circumference, and waist-to-hip ratio (WHR). Calcium intake represented both food and supplement sources of calcium. Lean and fat mass were determined from dual energy x-ray absorptiometry (DXA) total body scans, and abdominal fat mass was defined as fat mass between the top of the iliac crest and L1 on the DXA scan.

Results: Subjects were 60.5 ± 0.9 y/o with an average BMI of 26.9 ± 0.7 and percent body fat of 42.8 ± 1.2. Average calcium intake was 1151 ± 83 g/d. There was a significant inverse relationship between calcium intake and percent body fat (r = ?0.36, p < 0.01) and abdominal fat mass (r = ?0.25, p < 0.05), but there was no significant correlation between calcium intake and body mass index, fat mass, lean mass, waist circumference, or WHR. When kcalories were controlled, the inverse correlation between dietary calcium intake and percent body fat remained (r = ?0.24, p < 0.05). Total fat was significantly greater (p < 0.05) in the low dairy intake (1–2 servings/d) vs. high dairy intake group (3–4 servings/d), but there were no significant differences between the groups in other body composition variables.

Conclusions: Increased calcium intake was associated with lower percent body fat and higher dairy intake was associated with lower fat mass in postmenopausal women, but there was no association between calcium intake and body fat distribution measures in this population.     

Effects of Palm Stearin versus Butter in the Context of Low-Carbohydrate/High-Fat and High-Carbohydrate/Low-Fat Diets on Circulating Lipids in a Controlled Feeding Study in Healthy Humans

Background. Foods rich in saturated fatty acids (SFAs) have been discouraged by virtue of their cholesterol-raising potential, but this effect is modulated by the food source and background level of carbohydrate. Objective. We aimed to compare the consumption of palm stearin (PS) versus butter on circulating cholesterol responses in the setting of both a low-carbohydrate/high-fat (LC/HF) and high-carbohydrate/low-fat (HC/LF) diet in healthy subjects. We also explored effects on plasma lipoprotein particle distribution and fatty acid composition. Methods. We performed a randomized, controlled-feeding, cross-over study that compared a PS- versus a Butter-based diet in a group of normocholesterolemic, non-obese adults. A controlled canola oil-based ‘Run-In’ diet preceded the experimental PS and Butter diets. All diets were eucaloric, provided for 3-weeks, and had the same macronutrient distribution but varied in primary fat source (40% of the total fat). The same Run-In and cross-over experiments were done in two separate groups who self-selected to either a LC/HF (n = 12) or a HC/LF (n = 12) diet track. The primary outcomes were low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein (HDL)-C, triglycerides, and LDL particle distribution. Results. Compared to PS, Butter resulted in higher LDL-C in both the LC/HF (13.4%, p = 0.003) and HC/LF (10.8%, p = 0.002) groups, which was primarily attributed to large LDL I and LDL IIa particles. There were no differences between PS and Butter in HDL-C, triglycerides, or small LDL particles. Oxidized LDL was lower after PS than Butter in LC/HF (p = 0.011), but not the HC/LF group. Conclusions. These results demonstrate that Butter raises LDL-C relative to PS in healthy normocholesterolemic adults regardless of background variations in carbohydrate and fat, an effect primarily attributed to larger cholesterol-rich LDL particles.     

Impact of olive oil-rich diet on serum omentin and adiponectin levels: a randomized cross-over clinical trial among overweight women

This study aimed to investigate the effect of olive oil-rich diet on omentin and adiponectin concentrations. This cross-over randomized trial included 17 overweight women. Participants were assigned to consume either a usual (16% saturated fatty acids [SFA] and 8% monounsaturated fatty acid [MUFA]) or an olive oil-rich diet (16% MUFA and 8% SFA) for 6 weeks crossing over after a 2-week washout period. There was no significant difference in the changes of omentin between two dietary interventions. However, in the adjusted model for polyunsaturated fatty acids and fat mass, usual diet tended to decrease omentin levels whilst olive oil-rich diet tended to increase (?56.1?±?32.0 versus 40.6?±?32.0?ng/mL; p?=?.056). Adiponectin levels increased during two periods, but changes were greater during olive oil-rich diet with a trend toward significance (4.8?±?3.0 versus 13.4?±?3.0?μg/mL; p?=?.06). Consumption of olive oil-rich diet tended to increase omentin and adiponectin in comparison with the usual diet.     

Effect of Low-Energy-Dense Diet Rich in Multiple Functional Foods on Weight-Loss Maintenance,Inflammation, and Cardiovascular Risk Factors: A Randomized Controlled Trial

Background: There are no investigations regarding the effects of consuming low-energy-dense diets rich in multiple functional foods on weight-loss maintenance, inflammatory markers, and cardiovascular disease (CVD) risk factors simultaneously.

Method: This randomized controlled trial design was conducted on 90 men and women who were under a previous weight loss diet. Three months of intervention with recruitment at Allzahra Hospital, Isfahan, Iran, was done. Intervention was conducted following achieving 7–11 kg weight loss. Participants were encouraged to consumed these three: an isocaloric control diet (50% of energy from carbohydrate, 35% from fat, 15% from protein), a low-glycemic-index diet (LE) (60% from carbohydrate, 25% from fat, and 15% from protein), and a low-glycemic-index diet rich in multiple functional foods (LE + FF) (60% from carbohydrate, 25% from fat, and 15% from protein). Fasting blood glucose, serum insulin level, lipid profiles, inflammatory markers, adiponectin, systolic and diastolic blood pressure, and anthropometric measurements were assessed using standard guidelines.

Results: The percent changes of weight, waist, and body mass index (BMI), systolic and diastolic blood pressure, malondialdehyde (MDA), high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor (TNF) α, total cholesterol, low-density lipoprotein (LDL) cholesterol, triglyceride, and fasting blood glucose (FBS) were substantially more decreased in the LE + FF group compared to the LE and control groups (p ≤ 0.03). Percent change of adiponectin among the LE + FF group was significantly more enhanced (7.29 ± 0.10) compared with the LE group (1.28 ± 0.20) (p = 0.001). Significantly more increment in the percent change of total antioxidant capacity (TAC) (6.91 ± 0.10) was obtained among the LE + FF group compared to the LE group (1.79 ± 0.04).

Conclusions: This study provides established evidence supporting the beneficial effects of a low-energy-dense diet rich in multiple functional foods diet on improving weight-loss maintenance, inflammation, and cardiovascular risk factors.     

Weight Loss Is More Important Than the Diet Type in Improving Adiponectin Levels Among Overweight/Obese Adults

Objective: The study objective was to compare the effect of a standard calorie- and fat-restricted diet (STD-D) and a calorie- and fat-restricted lacto-ovo-vegetarian diet (LOV-D) on total and high-molecular-weight (HMW) adiponectin levels after 6 months of behavioral intervention.

Design: This study is an ancillary study to a randomized clinical trial.

Subjects: Subjects included 143 overweight/obese adults (STD-D = 79; LOV-D = 64).

Intervention: Both groups received the same standard behavioral intervention; the only difference was that LOV-D participants were instructed to eliminate meat, poultry, and fish from their diet.

Measures: Weight, dietary intake with the 3-day food diary, and total and HMW adiponectin levels were measured.

Results: Both groups significantly increased total (STD-D +7.2 ± 17.8%; LOV-D +9.4 ± 21.8%) and HMW adiponectin levels (STD-D +18.5 ± 32.9%; LOV-D +15.8 ± 34.5%; ps < 0.05) with no significant differences between the groups. We found significant associations between weight loss and increases in total (β (SE) = ?.071(.27); p = 0.003) and HMW adiponectin (β (SE) = ?1.37(.47); p = 0.001) levels independent of the diet type. Weight loss at the higher quartile was associated with improvements of adiponectin levels (p < 0.05).

Conclusion: Weight loss was associated with increased total and HMW adiponectin levels regardless of the diet type. Enhancing weight loss may be a means to improve adiponectin levels.     

Acute effects of the very low carbohydrate diet on sleep indices

Abstract

Objective: We compared the effect of short-term consumption of a very low carbohydrate (VLC) diet over 48 h to a control mixed diet on sleep indices in healthy, non-obese men.

Design: This study employed a repeated-measure design where subjects were given isocaloric (2400 kcal) diets and matching evening test meals (4 h before usual bed-time), which were either mixed low-fat, high carbohydrate (15.5%, 12.5% and 72% of energy from protein, fat and carbohydrate, respectively) or VLC (38%, 61% and < 1% of energy from protein, fat and carbohydrate, respectively). Polysomnographic testing was performed on the familiarization and control night, 4 h after the first VLC test meal (acute phase) and 48 h (ketosis phase) following commencement of the VLC diet.

Subjects: Fourteen healthy, non-obese men (aged 18–35 years; body mass index 23.4 ± 1.9 kg/m²) who were good sleepers took part in the study.

Measurement: Objective sleep was recorded using a computerized sleep system. Urine ketone level was monitored with reagent strips before the evening test meals and at bed-time on the control night, during the VLC acute and ketosis phases. Blood glucose level was measured with a glucometer before the evening test meal until 120 min following the meal. Hunger and fullness were assessed immediately after the meal until bed-time with Likert scales.

Results: The proportion of rapid-eye movement (REM) sleep to total sleep time was significantly reduced at the VLC acute and VLC ketosis when compared to the control night (P = 0.006; n = 11 and P = 0.05; n = 14, respectively). The percentage of slow wave sleep (SWS) significantly increased for both the VLC acute (17.7 ± 6.7) and ketosis (17.8 ± 6.1) phases compared to control (13.9 ± 6.3), P = 0.02 for both phases.

Conclusions: In healthy, good sleepers, the VLC diet over the short-term promotes increases in the percentage of SWS (deep sleep stage 4) and a reduction in the percentage of REM sleep ('dreaming' sleep) compared to the control mixed diet. The sleep changes may be linked to the metabolism of the fat content of the VLC diet.     

Symposium on Advances in Clinical Nutrition. The American College of Nutrition's 29th annual meeting. September 14-16, 1988, New Orleans,Louisiana. Abstracts.

Objective: To examine the safety and efficacy of a chitosan dietary supplement on body composition under free-living conditions.

Design: In a randomized, double-blinded, placebo-controlled dietary intervention protocol, subjects were assigned to a treatment group (TRT), a placebo group (PLA) and a control group (CTL).

Subjects: A total of 150 overweight adults enrolled; 134 (89.3%) completed the study; 111 (82.8%) were women who were similarly distributed in the three groups.

Intervention: The TRT group took six 500 mg chitosan capsules per day and both TRT and PLA groups wore pedometers during their waking hours and recorded daily step totals. The CTL group followed weight loss programs of their choice, and took the same baseline and ending tests.

Measures of Outcome: Outcome measures were Dual Energy X-ray Absorptiometry tests, fasting blood chemistries, and self-reported daily activity levels and caloric intakes.

Results: Compared to CTL, the TRT group lost more weight (?2.8 lbs vs. +0.8 lbs, p < 0.001) and fat mass (?2.6 lbs vs. +0.1 lbs, p = 0.006). Compared to PLA, the TRT group lost more weight (?2.8 lbs. vs. ?0.6 lbs, p = 0.03), % fat (?0.8% vs. +0.4%, p = 0.003), fat mass (?2.6 lbs vs. +0.6 lbs, p = 0.001) and had a greater body composition improvement index (BCI) (+2.4 lbs vs. ?1.9 lbs, p = 0.002).

Conclusions: These data provide evidence for the efficacy of a chitosan compound to facilitate the depletion of excess body fat under free-living conditions with minimal loss of fat-free or lean body mass.     

Effects of weight loss from a very-low-carbohydrate diet on endothelial function and markers of cardiovascular disease risk in subjects with abdominal obesity

BACKGROUND: The effects of a very-low-carbohydrate, high-saturated-fat weight-loss diet (LC) on brachial artery flow-mediated dilatation (FMD) and markers of endothelial function are unknown. OBJECTIVE: The effect of an LC on markers of endothelial function and cardiovascular disease (CVD) risk was compared with that of an isocaloric high-carbohydrate, low-saturated-fat diet (HC). DESIGN: FMD and markers of endothelial function (n = 70) and CVD risk were measured before and after 8 wk of weight loss. Ninety-nine subjects aged 50.0 +/- 8.3 y with a body mass index (in kg/m2) of 33.7 +/- 4.1 completed the study. RESULTS: Mean (+/-SD) FMD did not change significantly (P = 0.55) with either diet. Pulse wave velocity improved with both diets (P < 0.01). Endothelial markers, E- and P selectin, intracellular and cellular-adhesion molecule-1, tissue-type plasminogen activator, and plasminogen activator inhibitor-1 decreased (P < 0.001), with no diet effect. Adiponectin did not change significantly. More weight (P = 0.05 for diet x time interaction) and more abdominal fat mass (P = 0.05 for diet x time interaction) were lost with the LC than with the HC. LDL cholesterol decreased more with the HC than with the LC (P < 0.05, time x diet), and C-reactive protein decreased more with the HC than with the LC (P < 0.05 for diet x time interaction). Homocysteine increased more with the LC (P < 0.01 for diet x time interaction). Folate decreased with the LC and increased with the HC (P < 0.05, time; P < 0.001 for diet x time interaction). CONCLUSION: An LC does not impair FMD. We observed beneficial effects of both diets on most of the CVD risk factors measured. This trial was registered with the Australian Clinical Trials Registry as ACTR N0 12606000203550.     

Effects of a Short-Term “Fat Adaptation with Carbohydrate Restoration” Diet on Metabolic Responses and Exercise Performance in Well-Trained Runners

Periodized carbohydrate availability can enhance exercise capacity, but the effects of short-term fat adaptation carbohydrate restoration (FACR) diets on metabolic responses and exercise performance in endurance athletes have not been conclusively determined. This study aimed to investigate the effect of a FACR diet on measures of resting metabolism, exercise metabolism, and exercise performance. Well-trained male runners (n = 8) completed a FACR dietary intervention (five days’ carbohydrate < 20% and fat > 60% energy, plus one-day carbohydrate ≥ 70% energy), and a control high-carbohydrate (HCHO) diet for six days (carbohydrate > 60% energy; fat < 20% energy) in a randomized crossover design. Pre- and post-intervention metabolic measures included resting metabolic rate (RMR), respiratory quotient (RQ), maximum fat oxidation rate during exercise (MFO), and maximum fat oxidation intensity (FATmax). Measures of exercise performance included maximal oxygen uptake (VO₂max), running economy (RE), and 5 km running time trial (5 km-TT). In FACR compared with HCHO, there were significant improvements in FATmax (p = 0.006) and RE (p = 0.048). There were no significant differences (p > 0.05) between FACR and HCHO in RMR, RQ, VO₂max, or 5 km-TT. Findings suggest that a short-term (six days) FACR diet may facilitate increased fat oxidation and submaximal exercise economy but does not improve 5 km-TT performance.