Meal-induced thermogenesis and macronutrient oxidation in lean and obese women after consumption of carbohydrate-rich and fat-rich meals

Objective

To examine differences in meal-induced thermogenesis and macronutrient oxidation between lean and obese women after consumption of two different isocaloric meals, one rich in carbohydrate (CHO) and one rich in fat.

Methods

A total of 19 lean and 22 obese women were studied on two occasions, 1 wk apart. In one visit they consumed a CHO-rich meal and in the other visit a fat-rich meal. The two meals were isocaloric and were given in random order. Resting energy expenditure and macronutrient oxidation rates were measured and calculated in the fasting state and every hour for 3 h after meal consumption.

Results

Meal-induced thermogenesis was not different between lean and obese subjects after the CHO-rich (P = 0.89) or fat-rich (P = 0.32) meal, but it was significantly higher after the CHO-rich compared with the fat-rich meal in the lean and the obese individuals (P < 0.05). Protein oxidation rate increased slightly but significantly after the test meals in both groups (P < 0.01). Fat oxidation rate decreased after consumption of the CHO-rich meal (P < 0.001), whereas it increased after consumption of the fat-rich meal in both groups (P < 0.01). CHO oxidation rate increased in both groups after consumption of the CHO-rich meal (P < 0.001). Oxidation rates of protein, fat, and CHO during the experiment were not significantly different between lean and obese participants.

Conclusion

Meal-induced thermogenesis and macronutrient oxidation rates were not significantly different between lean and obese women after consumption of a CHO-rich or a fat-rich meal.     

A structured diet and exercise program promotes favorable changes in weight loss, body composition, and weight maintenance

Background

A number of diet and exercise programs purport to help promote and maintain weight loss. However, few studies have compared the efficacy of different methods.

Objective

To determine whether adherence to a meal-replacement–based diet program (MRP) with encouragement to increase physical activity is as effective as following a more structured meal-plan–based diet and supervised exercise program (SDE) in sedentary obese women.

Design

Randomized comparative effectiveness trial.

Participants/setting

From July 2007 to October 2008, 90 obese and apparently healthy women completed a 10-week university-based weight loss trial while 77 women from this cohort also completed a 24-week weight maintenance phase.

Intervention

Participants were matched and randomized to participate in an MRP or SDE program.

Main outcome measures

Weight loss, health, and fitness-related data were assessed at 0 and 10 weeks on all subjects as well as at 14, 22, and 34 weeks on participants who completed the weight maintenance phase.

Statistical analyses performed

Data were analyzed by multivariate analysis of variance for repeated measures.

Results

During the 10-week weight loss phase, moderate and vigorous physical activity levels were significantly higher in the SDE group with no differences observed between groups in daily energy intake. The SDE group lost more weight (−3.1±3.7 vs −1.6±2.5 kg; P=0.03); fat mass (−2.3±3.5 vs −0.9±1.6 kg; P=0.02); centimeters from the hips (−4.6±7 vs −0.2±6 cm; P=0.002) and waist (−2.9±6 vs −0.6±5 cm; P=0.05); and, experienced a greater increase in peak aerobic capacity than participants in the MRP group. During the 24-week maintenance phase, participants in the SDE group maintained greater moderate and vigorous physical activity levels, weight loss, fat loss, and saw greater improvement in maximal aerobic capacity and strength.

Conclusions

In sedentary and obese women, an SDE-based program appears to be more efficacious in promoting and maintaining weight loss and improvements in markers of health and fitness compared to an MRP type program with encouragement to increase physical activity.     

An effective lifestyle intervention in overweight children: one-year follow-up after the randomized controlled trial on "Obeldicks light"

Background & aims

Lifestyle interventions address primarily obese children, while interventions tailored to overweight but not obese children are scarce. The effectiveness of the lifestyle intervention “Obeldicks light” based on physical activity training, nutrition education, and behavior counseling for overweight children and their parents has been demonstrated by a randomized controlled trial. Here, we present the 12 months follow-up analysis of these children after end of intervention.

Methods

Degree of overweight (BMI and SDS-BMI), waist circumference, skinfold thickness, bioimpedance analyses (BIA), and blood pressure were determined in 76 overweight (BMI>90^th≤97^th percentile) children (mean age 11.8 ± 1.8years, 67% females, mean BMI 24.3 ± 1.9 kg/m²) participating in the evaluation study of “Obeldicks light” at onset of intervention (T0), end of 6 months intervention (T1), 6 months after end of intervention (T2) and 12 months after end of intervention (T3). Comparisons were performed on an intention-to-treat approach.

Results

The drop-out rate was 4% in the intervention period and additional 3% during follow-up. The children reduced significantly (p < 0.001) their SDS-BMI in the intervention period between T0 and T1 (−0.27 ± 0.23; p < 0.001). This SDS-BMI reduction remained stable at T2 (T0-T2:-0.26 ± 0.31; p < 0.001) and T3 (T0-T3:-0.26 ± 0.39; p < 0.001). SDS-BMI reductions were independent from age and gender. Body fat measured by skinfold thickness and BIA, waist circumference, and blood pressure decreased significantly in the intervention period and remained stable in the follow-up period as well.

Conclusions

The lifestyle intervention “Obeldicks light” was effective in reducing degree of overweight, fat mass, waist circumference, and blood pressure both at end of intervention and in a 12 months follow-up period.     

Prognostic value of changes in lean and fat mass in alcoholics

Background & aims

The prognostic value of nutritional status and/or lean and fat mass assessed by dual-energy X-ray absorptiometry (DEXA) has been widely analyzed, in both alcoholics and non-alcoholics. However, the prognostic value of changes in fat and lean mass over time in alcoholics has scarcely been studied, nor has the effect of alcohol abstinence on these changes.

Methods

From an initial cohort of 113 alcoholic patients, 70 prospectively underwent two DEXA assessments six months apart. One hundred and five patients (including 66 of those who underwent two DEXA assessments) were followed up for 34.9 ± 36.4 months (median = 18 months, interquartile range = 7.25–53.75 months). During this follow-up period, 33 died (including 20 of those who had undergone a second DEXA assessment).

Results

Forty-two of the 70 patients undergoing a second DEXA assessment had abstained from alcohol. Of these, 69.04% (29) gained left arm lean mass, compared with only 35.71% (10 of 28) of those who had continued drinking (χ² = 7.46; p = 0.006). Similar results were observed regarding right arm lean mass (χ² = 4.68; p = 0.03) and right leg lean mass (χ² = 7.88; p = 0.005). However, no associations were found between alcohol abstinence and changes in fat parameters. Analysis by means of Kaplan–Meier curves showed that loss of total lean mass, right leg lean mass, left leg lean mass and total fat mass were all significantly associated with reduced survival. However, within 30 months of the second evaluation, significant associations were observed between changes of all parameters related to lean mass, and mortality, but no association between changes in fat parameters and mortality.

Conclusions

Loss of lean mass over a period of six months after a first assessment is associated with worse prognosis in alcoholics, irrespective of whether they stop drinking during this period or not. Continued drinking is associated with greater loss of lean mass, but not with changes in fat mass.     

Plasma antioxidants and lipid oxidation after submaximal resistance exercise in men

Summary.Background: An increased generation of reactive oxygen species occurs during exercise.The aim of the study: We investigated whether changes in plasma antioxidants and lipid oxidation products after submaximal resistance exercise are detectable, and whether training status has any effect on changes.Methods: Seven resistance trained (RT, 31.3 ± 10.2 yrs) and ten non-resistance trained male subjects (NRT, 28.2 ± 3.9 yrs) performed a submaximal resistance exercise circuit (10 different exercises, 75% of 1-repetition maximum, 18.6 ± 1.1 minutes). Blood samples were taken before and immediately after exercise. Plasma antioxidants (AO), lipid oxidation products malondialdehyde (MDA) and conjugated dienes (CD) were measured using HPLC and/or photometric detection. Groups were compared using the Mann-Whitney U test, the exercise effect was tested using the Wilcoxon signed ranks test. P < 0.05 was regarded as significant.Results: -Tocopherol, -tocopherol, -carotene, lycopene, ascorbic acid,MDA and CD concentrations did not differ between groups at rest. There was a similar increase of fat soluble plasma AO in both groups after exercise, but not ascorbic acid. MDA increased also in both groups after exercise, but CD increased only in NRT.Conclusion: There is no difference in plasma AO and lipid oxidation products in RT and NRT at rest. After short time resistance exercise there is a mobilization of fat soluble AO. Despite mobilization of AO, oxidative stress occurs during submaximal resistance exercise, which is indicated by increased MDA and CD concentrations. As exercise induced an increase of CD only in NRT, it seems that regular resistance training partly prevents lipid peroxidation during exercise.     

Ingestion of a high-molecular-weight hydrothermally modified waxy maize starch alters metabolic responses to prolonged exercise in trained cyclists

Objective

We examined whether the ingestion of a hydrothermally modified starch (HMS) would alter metabolic and hormonal responses to prolonged cycling compared with maltodextrin (MAL).

Methods

Nine male cyclists (30 ± 2 y, 79.2 ± 2.1 kg, 4.7 ± 0.1 L of O₂/min, 7.5 ± 1.3 y training) fasted 10 h before cycling for 150 min at 70% peak oxygen consumption and completing a cycling-to-exhaustion trial at 100% peak oxygen consumption. Participants ingested 1g/kg of HMS or MAL 30 min before and within 10 min of completing the bout. Blood samples were provided every 15 min before, during, and 90 min after exercise. Expired gases were collected every 30 min during exercise. In a crossover, randomized, and double-blind fashion, identical testing was completed 1 wk later.

Results

Primary findings from this study were that 1) increases in serum glucose were greater during MAL (peak 9.5 mM) versus HMS (peak 7.4 mM, P ≤ 0.01), 2) insulin levels were significantly lower during HMS (peak 2.5 μIU/mL) versus MAL (peak 20.3 μIU/mL, P < 0.001), and 3) HMS was associated with greater fat breakdown as indicated by the increased serum non-esterified fatty acids (P < 0.01) and glycerol levels (P < 0.05).

Conclusion

Ingestion of a low-glycemic HMS before prolonged cycling exercise blunted the initial spike in serum glucose and insulin and increased the breakdown in fat compared with MAL.     

Oral sensitivity to oleic acid is associated with fat intake and body mass index

Background & aims

Taste sensitivity to fatty acids influences food ingestion and may regulate fat intake and body weight status. Fatty acids are detected via homologous receptors within the mouth and gastrointestinal (GI) tract, where attenuated sensitivity may be associated with greater fat intake and BMI. This study aimed to extend observations surrounding fatty acid taste, specifically the types of foods consumed and dietary behaviours that may be associated with fatty acid taste sensitivity.

Methods

51 subjects (41 female; BMI, 21.4 ± 0.46 kg/m², age, 20 ± 0.52 yrs, 10 male; BMI, 23.6 ± 1.4 kg/m², age, 22 ± 1 yrs) were screened for oral sensitivity to oleic acid (3.8 mM) using triplicate sensory evaluations, and classified as hypersensitive; (3/3 correct identifications), or hyposensitive, (<3/3). Fat-taste perception (using sensory-matched custards made with 0, 2, 6, 10% oil), recent diet (4-day diet record) and food habits and behaviours (food habits and behaviours questionnaire) were also established.

Results

75% (n = 38) of subjects were classified as hyposensitive to oleic acid and these subjects differed from those who were classified as hypersensitive. Hyposensitive subjects consumed significantly more energy, fat, saturated fat, fatty foods (butter, meat, dairy), had greater BMI and were less perceptive of small changes in the fat content of custard (all P < 0.05), compared to hypersensitive subjects.

Conclusion

An inability to perceive low concentrations of fatty acids in foods was associated with greater consumption of fatty foods, specifically butter, meat, dairy, and increasing BMI.     

The increase in physical performance and gain in lean and fat mass occur in prepubertal children independent of mode of school transportation. One year data from the prospective controlled Pediatric Osteoporosis Prevention (POP) Study

Background

The aim of this 12-month study in pre-pubertal children was to evaluate the effect of school transportation on gain in lean and fat mass, muscle strength and physical performance.

Methods

Ninety-seven girls and 133 boys aged 7-9 years from the Malmö Pediatric Osteoporosis Prevention Study were included. Regional lean and fat mass were assessed by dual energy X-ray absorptiometry, isokinetic peak torque of knee extensors and flexors by a computerised dynamometer and physical performance by vertical jump height. Level of physical activity was assessed by accelerometers. The 12-month changes in children who walked or cycled to school were compared with changes in those who travelled by bus or car.

Results

There were no differences in baseline or annual changes in lean or fat mass gain, muscle strength or physical performance between the two groups. All children reached the internationally recommended level of 60 minutes per day of moderate or high physical activity by accelerometers.

Conclusion

The choice of school transportation in pre-pubertal children seems not to influence the gain in lean and fat mass, muscle strength or functional ability, probably as the everyday physical activity is so high that the mode of school transportation contributes little to the total level of activity.

     

No effects of low and high consumption of dairy products and calcium supplements on body composition and serum lipids in Puerto Rican obese adults

Objective

Epidemiologic studies have shown that a high calcium intake is related to lower body weight, fat, and serum lipids in obese individuals. However, clinical studies have shown inconclusive results. The present study was conducted to determine if dairy or calcium supplementation alters body composition or serum lipids in Puerto Rican obese adults without dietary energy restriction or exercise.

Methods

A 21-wk randomized clinical trial was conducted in 30 obese adults, aged 21-50 y, with usual calcium intakes <700 mg/d. Subjects were randomly assigned to the following: high dairy (∼1300 mg/d of calcium from dairy products by substituting foods); high calcium (∼1300 mg/d of calcium; ∼700 mg/d from diet and 600 mg/d from a supplement); or placebo. Subjects were asked to continue their established dietary intake (except for the high dairy group) and their physical activity during the study. Body weight was measured monthly; body fat, bone, and serum lipids (total cholesterol, high-density lipoprotein, low-density lipoprotein, and triacylglycerol) were measured at baseline and at 21 wk. Pairwise differences in study endpoints among the groups were assessed using ANOVA and post-hoc analysis.

Results

Grand mean calcium intake was 1200 ± 370 (median 1187) mg/d in the high dairy group, 1171 ± 265 (median 1165) mg/d in the high calcium group, and 668 ± 273 (median 691) mg/d in the control group, which was significantly lower compared to the two treatment groups (P < 0.001). There were no significant group effects in any of the outcome variables.

Conclusion

A high dairy or calcium diet alone did not alter body composition or serum lipids profile in a sample of Puerto Rican obese adults.     

Effects of Adipocyte Aryl Hydrocarbon Receptor Deficiency on PCB-Induced Disruption of Glucose Homeostasis in Lean and Obese Mice

Background

Coplanar polychlorinated biphenyls (PCBs) promote adipocyte inflammation and impair glucose homeostasis in lean mice. The diabetes-promoting effects of lipophilic PCBs have been observed only during weight loss in obese mice. The molecular mechanisms linking PCB exposures to impaired glucose metabolism are unclear.

Objectives

In this study we tested the hypothesis that coplanar PCBs act at adipocyte aryl hydrocarbon receptors (AhRs) to promote adipose inflammation and impair glucose homeostasis in lean mice and in obese mice during weight loss.

Methods and Results

PCB-77 administration impaired glucose and insulin tolerance in LF (low fat diet)–fed control (AhR^fl/fl) mice but not in adipocyte AhR–deficient mice (AhR^AdQ). Unexpectedly, AhR^AdQ mice exhibited increased fat mass when fed a standard LF or high fat (HF) diet. In mice fed a HF diet, both genotypes became obese, but AhR^AdQ mice administered vehicle (VEH) exhibited increased body weight, adipose mass, adipose inflammation, and impaired glucose tolerance compared with AhR^fl/fl controls. Impairment of glucose homeostasis in response to PCB-77 was not observed in obese mice of either genotype. However, upon weight loss, AhR^fl/fl mice administered PCB-77 exhibited increased abundance of adipose tumor necrosis factor-α (TNF-α) mRNA and impaired glucose homeostasis compared with those administered VEH. In contrast, PCB-77 had no effect on TNF-α or glucose homeostasis in AhR^AdQ mice exhibiting weight loss.

Conclusions

Our results demonstrate that adipocyte AhR mediates PCB-induced adipose inflammation and impairment of glucose homeostasis in mice. Moreover, deficiency of AhR in adipocytes augmented the development of obesity, indicating that endogenous ligand(s) for AhR regulate adipose homeostasis.

Citation

Baker NA, Shoemaker R, English V, Larian N, Sunkara M, Morris AJ, Walker M, Yiannikouris F, Cassis LA. 2015. Effects of adipocyte aryl hydrocarbon receptor deficiency on PCB-induced disruption of glucose homeostasis in lean and obese mice. Environ Health Perspect 123:944–950; http://dx.doi.org/10.1289/ehp.1408594     

Accuracy of direct segmental multi-frequency bioimpedance analysis in the assessment of total body and segmental body composition in middle-aged adult population

Background & aims

Body composition measurement is a valuable tool for assessing nutritional status and physical fitness in a variety of clinical settings. Although bioimpedance analysis (BIA) can easily assess body composition, its accuracy remains unclear. We examined the accuracy of direct segmental multi-frequency BIA technique (DSM-BIA) in assessing different body composition parameters, using dual energy X-ray absorptiometry (DEXA) as a reference standard.

Methods

A total of 484 middle-aged participants from the Leiden Longevity Study were recruited. Agreements between DSM-BIA and DEXA for total and segmental body composition quantification were assessed using intraclass correlation coefficients and Bland–Altman plots.

Results

Excellent agreements were observed between both techniques in whole body lean mass (ICC female = 0.95, ICC men = 0.96), fat mass (ICC female = 0.97, ICC male = 0.93) and percentage body fat (ICC female = 0.93, ICC male = 0.88) measurements. Similarly, Bland–Altman plots revealed narrow limits of agreements with small biases noted for the whole body lean mass quantification but relatively wider limits for fat mass and percentage body fat quantifications. In segmental lean muscle mass quantification, excellent agreements between methods were demonstrated for the upper limbs (ICC female≥0.91, ICC men≥0.87) and lower limbs (ICC female≥0.83, ICC male≥0.85), with good agreements shown for the trunk measurements (ICC female = 0.73, ICC male = 0.70).

Conclusions

DSM-BIA is a valid tool for the assessments of total body and segmental body composition in the general middle-aged population, particularly for the quantification of body lean mass.     

Effect of prolonged intravenous glucose and essential amino acid infusion on nitrogen balance, muscle protein degradation and ubiquitin-conjugating enzyme gene expression in calves

Background

Consumption of a mixed meal increases postprandial carbohydrate utilization and decreases fat oxidation. On the other hand, acute endurance exercise increases fat oxidation and decreases carbohydrate utilization during the post-exercise recovery period. It is possible that the resulting post-exercise increase in circulating nonesterified fatty acids could attenuate the ability of ingested carbohydrate to inhibit lipid oxidation. The purpose of this study was to determine whether prior exercise attenuates the usual meal-induced decline in lipid oxidation.

Methods

Six healthy, physically active young subjects (x age = 26.3 years, 4 males, 2 females) completed three treatments in random order after a ~10 h fast: (a) Exercise/Carbohydrate (Ex/CHO) – subjects completed a bout of exercise at 70% VO_2peak (targeted net energy cost of 400 kcals), followed by consumption of a carbohydrate-rich meal; (b) Exercise/Placebo (Ex/Placebo) – subjects completed an identical bout of exercise followed by consumption of a placebo; and (c) No Exercise/Carbohydrate (NoEx/CHO) – subjects sat quietly rather than exercising and then consumed the carbohydrate-rich meal. Blood samples were obtained before and during the postprandial period to determine plasma glucose, insulin, and non-esterified fatty acids (NEFA). Respiratory gas exchange measures were used to estimate rates of fat and carbohydrate oxidation.

Results

Plasma NEFA were approximately two-fold higher immediately following the two exercise conditions compared to the no-exercise condition, while meal consumption significantly increased insulin and glucose in both Ex/CHO and NoEx/CHO. NEFA concentrations fell rapidly during the 2-h postprandial period, but remained higher compared to the NoEx/CHO treatment. Carbohydrate oxidation increased rapidly and fat oxidation decreased in response to the meal, with no differences in the rates of carbohydrate and fat oxidation during recovery between the Ex/CHO and NoEx/CHO conditions.

Conclusion

The plasma NEFA concentration is increased during the post exercise period, which is associated with elevated fat oxidation when no meal is consumed. However, when a mixed meal is consumed immediately following exercise, the initially elevated plasma NEFA concentration decreases rapidly, and postexercise fat oxidation during this 2-h postexercise, postprandial period is no higher than that of the 2-h postprandial period without prior exercise.     

Positive muscle protein net balance and differential regulation of atrogene expression after resistance exercise and milk protein supplementation

Purpose

Resistance exercise and amino acid availability are positive regulators of muscle protein net balance (NB). However, anabolic responses to resistance exercise and protein supplementation deserve further elucidation. The purpose was to compare intakes of whey, caseinate (both: 0.30 g/kg lean body mass), or a non-caloric control after heavy resistance exercise on protein turnover and mRNA expressions of forkhead homeobox type O (FOXO) isoforms, muscle RING finger 1 (MuRF1), and Atrogin1 in young healthy males.

Methods

Protein turnover was determined by stable isotope-labeled leucine and femoral arteriovenous blood samples at rest and during 6-h recovery. Muscle biopsies were collected at ?60 min (rest) and at 60, 210, and 360 min in the recovery period.

Results

During recovery, leucine NB was significantly higher in the protein groups compared to control (P < 0.001). Differences in leucine NB, rate of disappearance, and oxidation were observed in the early recovery period between whey and caseinate. FOXO1A and MuRF1 were upregulated at 60 and 210 min, and, in contrast, FOXO3 and Atrogin1 were downregulated at 210 and 360 min. For leucine rate of appearance and all FOXO and atrogene mRNA expressions, no differences were observed between groups.

Conclusions

Whey and caseinate were equally superior to control in the 6-h recovery period and displayed temporal differences with whey having a fast and superior effect in the early part of the recovery period. Effects on mRNA expressions indicate different regulatory mechanisms on the ubiquitin ligases MuRF1 and Atrogin1 in recovery from heavy resistance exercise.     

Fat and carbohydrate balances during adaptation to a high-fat

BACKGROUND: Dietary fat contents are highly variable. Failure to compensate for the positive fat balance that occurs during the shift to a high-fat, low-carbohydrate diet by increasing energy expenditure or by decreasing food intake may result in the gain of fat mass. OBJECTIVE: The objective of this study was to investigate the time course of fat oxidation during adaptation to an isoenergetic high-fat, low-carbohydrate diet. DESIGN: After a 5-d control diet, dietary fat was increased from 37% of energy to 50% of energy for 4 d in 6 healthy, young lean men. Respiratory quotient and substrate macronutrient oxidation and balance were measured in a respiratory chamber. Fasting concentrations of insulin, glucose, and triacylglycerol; maximal oxygen consumption (f1.gif" BORDER="0">O(2)max) during treadmill exercise; and free-living energy expenditure were determined. Body fat was measured by dual-energy X-ray absorptiometry and visceral adipose tissue by computerized tomography. RESULTS: Compared with the baseline diet, the high-fat, low-carbohydrate diet resulted in positive fat and protein balances and a negative carbohydrate balance. Insulin concentration and the postabsorptive respiratory quotient were positively correlated with the fat balance during the high-fat, low-carbohydrate diet, whereas f1.gif" BORDER="0">O(2)max during treadmill exercise was negatively related to fat balance. With use of stepwise regression, f1.gif" BORDER="0">O(2)max was the best predictor of fat balance. There was a negative correlation between fat balance and carbohydrate balance (r(2) = 0.88). CONCLUSION: Both baseline insulin concentration and f1.gif" BORDER="0">O(2)max during treadmill exercise predict fat balance during the shift to a high-fat diet under isoenergetic conditions.     

Outcome of a hospital based multidisciplinary weight loss program in obese Filipino children

Background

Childhood obesity is becoming a problem for Filipino children with an increasing national prevalence of pediatric overweight and obesity. A multidisciplinary approach combining behavioral therapy with diet and exercise is often advocated as having the greatest impact in pediatric weight management.

Objective

To determine the effects of a weight loss program, which is a staged 3-mo, multidisciplinary intervention consisting of combined dietary, exercise, and behavioral methods in obese children.

Research methods and procedures

Prospective study done in a hospital-based weight management center; duration of study: 15 mo (November 2005 to January 2008); participants: 44 obese children (aged 5-17 y; body mass index [BMI] 85th-99th percentile); outcome measures: change in weight, BMI, BMI z-score (SD score); secondary measures included changes in waist circumference, blood pressure, and body fat. Statistical tests: paired t tests, χ² test, Wilcoxon ranked sum test, regression analysis, and ANOVA.

Results

At the end of the program, the patients demonstrated a decrease in weight, BMI, BMI z-score, body fat, systolic blood pressure, and waist circumference. Mean weight loss is 4.2 kg (P < 0.01) with an average of 5.3% weight loss; BMI decreased by 1.5 units (P < 0.01), BMI z-score by 0.15 (P < 0.004), body fat by 14% (P < 0.01), systolic blood pressure by 7.25 mm Hg (P < 0.05), and waist circumference by 5.4 cm (P < 0.05). Decrease in weight, BMI, and body fat were significantly correlated with number of sessions attended.

Conclusion

The use of a multidisciplinary 3-mo staged program resulted in an effective weight loss in obese Filipino children, which was directly related to the frequency of sessions attended.     

Consumption of a high β-glucan barley flour improves glucose control and fatty liver and increases muscle acylcarnitines in the Zucker diabetic fatty rat

Purpose

The soluble fiber β-glucan, a natural component of barley, has been shown to lower the postprandial glucose response and is thought to improve insulin resistance.

Methods

This study examined the effect of chronic consumption of the high β-glucan barley flour on glucose control, liver lipids and markers of muscle fatty acid oxidation in the Zucker diabetic fatty (ZDF) rat. Two groups of ZDF rats were fed diets containing either 6 % β-glucan in the form of barley flour or cellulose as a control for 6 weeks. A group of Zucker lean rats served as a negative control.

Results

The barley flour group had an increased small intestinal contents viscosity compared to the obese control group. After 6 weeks, the barley flour group had reduced glycated hemoglobin, lower relative kidney weights and a reduced area under the curve during a glucose tolerance test, indicating improved glucose control. Fasting plasma adiponectin levels increased in the barley flour group and were not different than the lean control group. ZDF rats on the barley flour diet had lower relative epididymal fat pad weights than the obese control and a greater food efficiency ratio. The barley flour group also had reduced liver weights and a decreased concentration of liver lipids. The barley flour group had significantly higher concentrations of muscle acylcarnitines, a metabolite generated during fatty acid oxidation.

Conclusion

These results show that chronic consumption of β-glucans can improve glucose control and decrease fatty liver in a model of diabetes with obesity.     

Resting energy expenditure and substrate utilisation rate in children with constitutional leanness or obesity

BACKGROUND & AIM: The influence of energy expenditure on body weight regulation, in the absence of organic disease, has never been studied in a paediatric population covering a broad range of body weights. The aim of this study was to investigate resting energy metabolism in children with constitutional leanness, normal body weight, or common obesity. METHODS: Fourteen children with constitutional leanness, 16 children with obesity, and controls were studied. Resting energy expenditure and postabsorptive substrate utilisation rate were measured by indirect calorimetry and body composition was assessed from skinfold thicknesses. RESULTS: As compared to the predicted value calculated from the regression equation of resting energy expenditure on fat-free mass in the controls, resting energy expenditure was decreased in lean children (P=0.002), whereas no difference was found in obese children. In obese children and the overall population, fat mass was positively correlated with fat oxidation rate. In each group and in the overall population, fat oxidation rate was positively correlated to resting energy expenditure. CONCLUSIONS: Constitutionally lean children have a low resting metabolic rate, probably adaptive in nature. In obese children, resting energy expenditure is increased in proportion to the fat-free mass, and fat balance is the main determinant of energy balance. These data suggest a constitutional regulation of body weight.     

Depressive Symptoms and Cardiorespiratory Fitness in Obese Adolescents

Purpose

Depressive symptoms in adolescents have been associated with reduced physical activity. However, existing studies have relied on questionnaire measures of physical activity, which may not necessarily reflect actual energy expenditures. We sought to evaluate the relationship between depressive symptoms and objectively measured cardiorespiratory fitness among severely obese adolescents.

Methods

One hundred thirty-four obese (body mass index [kg/m²]: ≥95th percentile) adolescent girls and boys (ages: 12-17 years) reported their depressive symptoms on the Children's Depression Inventory. Adolescents also participated in a maximal cycle ergometry exercise test to measure cardiorespiratory fitness. Body composition was assessed with dual-energy X-ray absorptiometry scanning.

Results

Among the 103 adolescents who reached maximal exertion, those with elevated depressive symptoms (16%) displayed poorer cardiorespiratory fitness than those without elevated depressive symptoms (maximal oxygen uptake: 1,873.2 ± 63.6 vs. 2,012.9 ± 28.6 mL/min, p < .05). Symptoms of anhedonia also were related to lower fitness levels (p < .05). These effects were observed after accounting for age, sex, race, and lean mass.

Conclusions

Among obese adolescents, elevated depressive symptoms are associated with poorer objectively measured cardiorespiratory fitness. Future experimental tests should investigate whether cardiorespiratory fitness acts as a mediator of adolescent depressive symptoms' effect on obesity or obesity-related health comorbidities.     

Diet-induced obese rats have higher iron requirements and are more vulnerable to iron deficiency

Purpose

Since obesity is associated with poorer iron status, the effects of diet-induced obesity on iron status and iron-regulatory pathways were examined.

Methods

Weanling male diet-induced obese sensitive (n = 12/diet group) and resistant (n = 12/diet group) rats were fed one of four high-fat, high-energy diets supplemented with 5 (5Fe, low), 15 (15Fe, marginal), 35 (35Fe, normal) or 70 (70Fe, high) mg iron/kg diet for 12 weeks. At the end of the study, rats in each diet group were categorised as obese (>19 %) or lean (<17 %) based on percentage body fat.

Results

Obese rats gained more weight, had larger total lean mass, consumed more food and showed greater feed efficiency compared with lean rats. Obese rats fed the 5Fe and 15Fe diets had poorer iron status than lean rats fed the same diet. Obese 5Fe rats had lower serum iron and more severe iron-deficiency anaemia. Obese 15Fe rats had lower mean corpuscular haemoglobin and liver iron concentrations. Hepcidin mRNA expression in liver and adipose tissue was similar for obese and lean rats. Iron concentration and content of the iron transporters divalent metal transporter 1 and ferroportin 1 in duodenal mucosa were also similar.

Conclusions

Obese rats that were larger, regardless of adiposity, had higher iron requirements compared with lean rats that appeared independent of hepcidin, inflammation and intestinal iron absorption. Higher iron requirements may have resulted from larger accretion of body mass and blood volume. Greater food consumption did not compensate for the higher iron needs, indicating increased susceptibility to iron deficiency.