Effects of aerobic exercise and obesity phenotype on abdominal fat reduction in response to weight loss

Visceral fat mass dynamics in a 2-year randomized STrength versus ENdurance training trial in people with obesity

AIM

To compare the effectiveness of strength versus endurance training on reducing visceral fat in individuals with obesity.

MATERIALS AND METHODS

For the STrength versus ENdurance (STEN) 24-month randomized clinical trial, we assigned 239 participants with abdominal obesity to either strength or endurance training (two to three times a week, 60 min/training session) in addition to standard nutritional counselling to promote a healthy diet. Changes in abdominal visceral adipose tissue (VAT) area quantified by magnetic resonance imaging after 12 months were defined as a primary endpoint.

RESULTS

Participants (aged 44 years, 74% women, body mass index: 37 kg/m2, mean VAT volume: 4050 cm3) had an approximately 50% retention rate and a 30% good training programme adherence at 12 months. There was no difference between strength and endurance training in VAT volume dynamics after 12 and 24 months (p = .13). Only in the good adherence group did we find a trend for reduced VAT volume in both training regimens. Independently of the exercise programme, there was a continuous trend for moderate loss of abdominal subcutaneous AT volume, body fat mass, body mass index and improved parameters of insulin sensitivity. Although parameters of physical fitness improved upon both exercise interventions, the dynamics of resting energy expenditure, glucose and lipid metabolism parameters were not different between the intervention groups and did not significantly improve during the 2-year trial (p > .05).

CONCLUSIONS

Despite heterogeneous individual training responses, strength and endurance training neither affected VAT volume nor key secondary endpoints differently.

Effects of various exercise types on visceral adipose tissue in individuals with overweight and obesity: A systematic review and network meta-analysis of 84 randomized controlled trials

The purpose of this systematic review and network meta-analysis (NMA) of randomized controlled trials (RCTs) was to investigate the effects of various exercise categories on visceral adipose tissue (VAT) and other anthropometric variables in individuals with overweight and obesity. A total of 84 RCTs (4836 patients) were included. Aerobic exercise (AE) of at least moderate intensity, resistance training (RT), AE combined with RT (AE + RT), and high-intensity interval training (HIIT) were beneficial for reducing VAT. A subgroup analysis showed that RT improves VAT in males and those with BF% < 40% but not in females and those with body fat percentage (BF%) ≥ 40%. AE, RT, AE + RT, and HIIT significantly improved weight (except RT), total body fat (TBF), body mass index (BMI), waist circumference (WC), and subcutaneous adipose tissue (SAT). Surface under the cumulative ranking curve (SUCRA) probability ranking showed that AE with vigorous intensity and HIIT have the highest probability of being the best exercise intervention for improving VAT, weight, TBF, BMI, WC, and SAT. These findings suggest that regular exercise can improve VAT in individuals with overweight and obesity. AE of vigorous intensity and HIIT may be the best exercise treatment, and RT is the least effective intervention.

A new approach to quantify visceral fat via bioelectrical impedance analysis and ultrasound compared to MRI

BACKGROUND

Visceral adipose tissue (VAT) has been linked to systemic proinflammatory characteristics, and measuring it accurately usually requires sophisticated instruments. This study aimed to estimate VAT applying a simpler method that uses total subcutaneous fat and total body fat (BF) measurements.

METHOD

As part of our experimental approach, the subcutaneous fat mass (SFT) was measured via US (SFTtotal), and VAT was quantified by assessing MRI data. Both parameters were added to obtain total body fat (BFcalc). Those results were then compared to values obtained from a bioelectrical impedance analysis (BFBIA). Multiple regression analyses were employed to develop a simplified sex-specific equation for SFT, which was subsequently used in conjunction with BFBIA to determine VAT (VATEq).

RESULT

We observed excellent reliability between BFBIA and BFcalc, with no significant difference in body fat values (20.98 ± 8.36 kg vs. 21.08 ± 8.81 kg, p = 0.798, ICC 0.948). VATEq_female/male revealed excellent reliability when compared to VATMRI, and no significant difference appeared (women: 0.03 ± 0.66 kg with a 95% CI ranging from -1.26 kg to 1.32 kg, p = 0.815, ICC: 0.955.; men: -0.01 ± 0.85 kg with a 95% CI ranging from -1.69 kg to 1.66 kg, p = 0.925, ICC: 0.952).

CONCLUSION

Taking an experimental approach, VAT can be determined without MRI.

Experimental evaluation of high intensity focused ultrasound for fat reduction of ex vivo porcine adipose tissue

PURPOSE

The present study was stimulated by the continuous growth of commercially available high intensity focused ultrasound (HIFU) systems for fat reduction. Herein, HIFU was utilised for fat ablation using a single-element ultrasonic transducer operating in thermal mode.

METHODS

The custom-made concave transducer that operates at 1.1 MHz was assessed on excised porcine adipose tissue for its ability to reduce fat. Ultrasonic sonications were executed on the adipose tissue utilising acoustical power between 14 and 75 W and sonication time in the range of 1-10 min. The mass of the adipose tissue sample was weighed afore and after ultrasonic sonications and the effect of the sonication on the mass change was recorded.

RESULTS

Mass change was linearly dependent with either increasing acoustical power or sonication time and was in the range of 0.46-1.9 g. High acoustical power of 62.5 W for a sonication time of 1 min and a power of 75 W for a sonication time of 5 min, respectively resulted in the formation of a lesion or possible cavitation on the piece of excised adipose tissue.

CONCLUSION

The study demonstrated the efficacy of the proposed transducer in achieving a reduction of excised fat tissue. The present findings indicate the potential use of the transducer in a HIFU system indicated for the reduction of subcutaneous adipose tissue where increased values of acoustical power can result in increased amounts of fat reduction.

Resistance Exercise Training Improves Metabolic and Inflammatory Control in Adipose and Muscle Tissues in Mice Fed a High-Fat Diet

This study investigates whether ladder climbing (LC), as a model of resistance exercise, can reverse whole-body and skeletal muscle deleterious metabolic and inflammatory effects of high-fat (HF) diet-induced obesity in mice. To accomplish this, Swiss mice were fed for 17 weeks either standard chow (SC) or an HF diet and then randomly assigned to remain sedentary or to undergo 8 weeks of LC training with progressive increases in resistance weight. Prior to beginning the exercise intervention, HF-fed animals displayed a 47% increase in body weight (BW) and impaired ability to clear blood glucose during an insulin tolerance test (ITT) when compared to SC animals. However, 8 weeks of LC significantly reduced BW, adipocyte size, as well as glycemia under fasting and during the ITT in HF-fed rats. LC also increased the phosphorylation of Akt_Ser473 and AMPK_Thr172 and reduced tumor necrosis factor-alpha (TNF-α) and interleukin 1 beta (IL1-β) contents in the quadriceps muscles of HF-fed mice. Additionally, LC reduced the gene expression of inflammatory markers and attenuated HF-diet-induced NADPH oxidase subunit gp91phox in skeletal muscles. LC training was effective in reducing adiposity and the content of inflammatory mediators in skeletal muscle and improved whole-body glycemic control in mice fed an HF diet.

A comparison of the impact of exercise training with dietary intervention versus dietary intervention alone on insulin resistance and glucose regulation in individual with overweight or obesity: a systemic review and meta-analysis

PURPOSE

Obesity is associated with the development of insulin resistance (IR) and type 2 diabetes for which exercise training (Ex) and dietary interventions (DI) are effective interventions that can improve IR. We therefore performed a systematic meta-analysis to compare the effect of Ex + DI compared with DI on IR and glucose homeostasis.

METHODS

PubMed and Cochrane Library were conducted up to May 2021. Meta-analyses were conducted to compare the effect of Ex + DI compared with DI on fasting glucose and insulin, IR and body weight. Standardized mean differences (SMDs), weighted mean differences (WMD) and 95% confidence intervals (95% CIs) were computed using random or fixed effect models.

RESULTS

Fifty studies involving 2864 participants with overweight or obesity were included in the meta-analysis. Ex + DI caused a larger decrease in fasting glucose (p = 0.001, 62 trials) and IR (p = 0.01, 29 trials) when compared with DI alone. There was no significant evidence, however, for a greater effect of Ex + DI on fasting insulin (p = 0.07, 48 trials) and body weight (p = 0.12, 58 trials), compared with DI alone.

CONCLUSION

Our results suggest that a combination of Ex and DI may be more effective than DI alone at improving IR and fasting glucose in individuals with overweight and obesity.

Comparisons of calorie restriction and structured exercise on reductions in visceral and abdominal subcutaneous adipose tissue: a systematic review

Exercise and low-calorie diets are common approaches taken to produce an energy deficit for weight loss in obesity. Changes in visceral and abdominal subcutaneous fat associated with weight loss are important questions but have not yet been concluded. We investigated the relationship between changes in visceral (VAT) and subcutaneous adipose tissue (SAT) areas obtained by abdominal imaging with the change in total body fat. The relevant databases were searched through January 2021 according to the PRISMA guidelines. Sixty-five studies were included. We found that the change in total body fat was associated with changes in both VAT and abdominal SAT areas, but the relationship between total body fat and the abdominal SAT area appeared stronger. Baseline values of VAT and abdominal SAT area were similar in the three treatment groups (calorie restriction, calorie restriction plus exercise, and exercise alone). The reduction in abdominal SAT area for a loss of 1 kg of total body fat was about 10 cm², which was similar among all the treatments. The change in VAT area (-26.3 cm²) was a similar level as the change in abdominal SAT area (-31.5 cm²) in the exercise, whereas in the calorie restriction with and without exercise, the change in VAT area (-33.6 and -51.6 cm², respectively) was approximately half of the reduction of SAT area (-65.1 and -87.2 cm², respectively). Absolute changes in VAT and abdominal SAT areas might differ between interventions for the exercise and calorie restriction with and without exercise.

Physiological Changes and Pathological Pain Associated with Sedentary Lifestyle-Induced Body Systems Fat Accumulation and Their Modulation by Physical Exercise

A sedentary lifestyle is associated with overweight/obesity, which involves excessive fat body accumulation, triggering structural and functional changes in tissues, organs, and body systems. Research shows that this fat accumulation is responsible for several comorbidities, including cardiovascular, gastrointestinal, and metabolic dysfunctions, as well as pathological pain behaviors. These health concerns are related to the crosstalk between adipose tissue and body systems, leading to pathophysiological changes to the latter. To deal with these health issues, it has been suggested that physical exercise may reverse part of these obesity-related pathologies by modulating the cross talk between the adipose tissue and body systems. In this context, this review was carried out to provide knowledge about (i) the structural and functional changes in tissues, organs, and body systems from accumulation of fat in obesity, emphasizing the crosstalk between fat and body tissues; (ii) the crosstalk between fat and body tissues triggering pain; and (iii) the effects of physical exercise on body tissues and organs in obese and non-obese subjects, and their impact on pathological pain. This information may help one to better understand this crosstalk and the factors involved, and it could be useful in designing more specific training interventions (according to the nature of the comorbidity).

Unsupervised Exercise Training Was Not Found to Improve the Metabolic Health or Phenotype over a 6-Month Dietary Intervention: A Randomised Controlled Trial with an Embedded Economic Analysis

Ectopic fat leads to metabolic health problems. This research aimed to assess the effectiveness of a hypocaloric diet intervention together with an unsupervised exercise training program in comparison with a hypocaloric diet alone to reduce ectopic fat deposition. Sixty-one premenopausal women with overweight or obesity participated in this controlled trial and were each randomised into either a usual care group (hypocaloric diet) or intervention group (hypocaloric diet + unsupervised exercise training). Ectopic fat deposition, metabolic parameters, incremental costs from a societal perspective and incremental quality-adjusted life years (QALYs) were assessed before, during and after the six-month intervention period. In the total sample, there was a significant decrease in visceral adipose tissue (VAT: -18.88 cm², 95% CI -11.82 to -25.95), subcutaneous abdominal adipose tissue (SAT: -46.74 cm², 95% CI -29.76 to -63.18), epicardial fat (ECF: -14.50 cm³, 95% CI -10.9 to -18.98) and intrahepatic lipid content (IHL: -3.53%, 95% CI -1.72 to -5.32). Consequently, an "adapted" economic analysis revealed a non-significant decrease in costs and an increase in QALYs after the intervention. No significant differences were found between groups. A multidisciplinary lifestyle approach seems successful in reducing ectopic fat deposition and improving the metabolic risk profile in women with overweight and obesity. The addition of unsupervised exercise training did not further improve the metabolic health or phenotype over the six months.

Combined Aerobic and Resistance Training Lowers Body Fat Percentage in Rural Black South African Women

Background: Obesity is currently one of the most dominating diseases affecting younger adults in South Africa. This is commonly caused by a poor lifestyle, which may lead to an increased risk of non-communicable diseases. Objectives: The aim of the study was to examine if a six-week concurrent resistance and aerobic training program could elicit body composition and cardiorespiratory changes in rural black college women. Methods: Forty sedentary black females (aged 18 - 25 years) were randomly assigned to a combined resistance and aerobic training (COM) group (n = 20) or a control group (n = 20). The COM group participated in four times weekly aerobic and resistance training. Aerobic training consisted of 30 minutes a session (week 1 - 3: cycling for 3 minutes at 60% heart rate reserve (HRR), followed by 2 minutes at 50% HRR; week 4 - 6: 3 minutes at 70% HRR, followed by 2 minutes at 60% HRR). Resistance training consisted of participants training at 50% of their one-repetition maximum (1-RM) for week 1 - 3, doing 3 sets of 15 repetitions; for week 4 - 6 at 60% 1-RM, doing 3 sets of 15 repetitions. Results: Following the intervention, the COM group significantly (P ≤ 0.05) decreased their body fat percentage when compared to the control group (P = 0.006; d = 0.9), while no significant changes were observed in waist-to-hip ratio (P = 0.223) and cardiorespiratory endurance (P = 0.260) in either group. Conclusions: Although body composition (especially waist circumference and body fat percentage) and cardiorespiratory fitness are recommended as the main targets of physical activity programs aimed at preventing CVD in college students, this study demonstrated that a six-week concurrent program improved body fat percentage, and not WHR and cardiorespiratory fitness, in sedentary rural college-aged females. Further, these findings suggest that one method of program design does not fit all populations and that exercise prescription should be targeted and not generalized.

Impact of physical activity and sedentary time on glycated hemoglobin levels and body composition: Cross-sectional study using outpatient clinical data of Japanese patients with type 2 diabetes

AIMS/INTRODUCTION

This study examined the association among sedentary time (ST), physical activity (PA), glycated hemoglobin and body composition in Japanese type 2 diabetes patients.

MATERIALS AND METHODS

Patients with type 2 diabetes who visited the outpatient clinic at Kawasaki Medical School Hospital, Okayama, Japan, comprised the study's participants. Self-administered International Physical Activity Questionnaire short forms were obtained and analyzed for 1,053 patients, including 158 patients for whom waist circumference and visceral fat accumulation were measured. From the questionnaire, three categorical data (low, moderate, high) and continuous data (METs/h/week) regarding PA and ST (min/day), respectively, were obtained.

RESULTS

The patients categorized as having low PA had significantly higher body mass index than those categorized as having high levels, after adjustment was made for confounders. Continuous data of PA were negatively associated with waist circumference and visceral fat accumulation. ST was positively associated with body mass index. After dividing the participants into four groups according to medians of ST and PA, the following categories were established: long ST and low PA, long ST but high PA, short ST but low PA and short ST and high PA. In terms of body mass index, short ST and high PA measured significantly lower than long ST and low PA. For waist circumference and visceral fat accumulation, short ST but low PA and short ST and high PA measured significantly lower than long ST and low PA and long ST but high.

CONCLUSIONS

These results imply that the combination of avoiding sedentary behavior and increasing PA might be important in the prevention bodyweight gain and in the avoidance of central obesity, respectively, in Japanese type 2 diabetes patients.

The impact of weight change on intra-abdominal and hernia volumes

BACKGROUND

Weight loss is often encouraged or required before open ventral hernia repair. This study evaluates the impact of weight change on total, intra-abdominal, subcutaneous, and hernia volume.

METHODS

Patients who underwent open ventral hernia repair from 2007 to 2018 with two preoperative computed tomography scans were identified. Scans were reviewed using 3D volumetric software. Demographics, operative characteristics, and outcomes were evaluated. The impact of weight change on intra-abdominal, subcutaneous, and hernia volume was assessed using Spearman's correlation coefficients and linear regression models.

RESULTS

A total of 250 patients met the criteria with a mean defect area of 155.6 ± 155.4 cm², subcutaneous volume of 6,800.0 ± 3,868.8 cm³, hernia volume of 915.7 ± 1,234.5 cm³, intra-abdominal volume equaling 4,250.2 ± 2,118.1 cm³, and time between computed tomography scans 13.9 ± 11.0 months. Weight change was associated with change in hernia, intra-abdominal, total, and subcutaneous volume (Spearman's correlation coefficients 0.17, 0.48, 0.51, 0.45, respectively, P ≤ 0.03 all values) and not associated in hernia length, width, or area (P ≥ 0.18 all values). A Δ5 kg was significantly associated with Δintra-abdominal volume (164.1 ± 30.0 cm³/Δ5 kg,P < .0001), Δtotal volume (209.9 ± 33.0 cm³/Δ5 kg, P < .0001), and Δsubcutaneous volume (234.4 ± 50.8 cm³/Δ5 kg, P < .0001). Per Δ5 kg, male patients had more than double the Δintra-abdominal, Δtotal, and Δsubcutaneous volume than did female patients. A weight change of 5 kg to10 kg was associated with approximately double the change in computed tomography parameters/Δ5 kg than any weight change after 10 kg. Regardless of weight change, all measured hernia parameters increased over time, with mean hernia volume of +40.6 ± 94.9 cm³/mo and area of +7.8 ± 13.3 cm²/mo (Spearman's correlation coefficient -0.03 to 0.07, P value 0.37-0.96).

CONCLUSION

Weight change is linearly correlated with intra-abdominal and subcutaneous fat gain or loss. Males show greater abdominal-related response to weight gain or loss. Hernia dimensions increase over time regardless of weight change.

Exercising the hepatobiliary-gut axis. The impact of physical activity performance

BACKGROUND

Physical inactivity puts the populations at risk of several health problems, while regular physical activity brings beneficial effects on cardiovascular disease, mortality and other health outcomes, including obesity, glycaemic control and insulin resistance. The hepatobiliary tract is greatly involved in several metabolic aspects which include digestion and absorption of nutrients in concert with intestinal motility, bile acid secretion and flow across the enterohepatic circulation and intestinal microbiota. Several metabolic abnormalities, including nonalcoholic fatty liver as well as cholesterol cholelithiasis, represent two conditions explained by changes of the aforementioned pathways.

MATERIALS AND METHODS

This review defines different training modalities and discusses the effects of physical activity in two metabolic disorders, that is nonalcoholic fatty liver disease (NAFLD) and cholelithiasis. Emphasis is given to pathogenic mechanisms involving intestinal bile acids, microbiota and inflammatory status.

RESULTS

A full definition of physical activity includes the knowledge of aerobic and endurance exercise, metabolic equivalent tasks, duration, frequency and intensity, beneficial and harmful effects. Physical activity influences the hepatobiliary-gut axis at different levels and brings benefits to fat distribution, liver fat and gallbladder disease while interacting with bile acids as signalling molecules, intestinal microbiota and inflammatory changes in the body.

CONCLUSIONS

Several beneficial effects of physical activity are anticipated on metabolic disorders linking liver steatosis, gallstone disease, gut motility, enterohepatic circulation of signalling bile acids in relation to intestinal microbiota and inflammatory changes.

Effects of exercise intervention on visceral fat in obese children and adolescents

INTRODUCTION

This meta-analysis study was aimed to assess the effects of exercise intervention on visceral fat in obese children and adolescents.

EVIDENCE ACQUISITION

Electronic database searches were performed in Academic Search Complete, CINAHL, Healthsource, MEDLINE, and SportDiscus, and from the earliest record to November 2017. Keywords included "exercise or training," "visceral fat," and "child or adolescent or youth." The inclusion criteria for eligible studies were as follows: 1) subjects were obese at baseline; 2) aged 6-19 years; 3) visceral fat was reported at baseline and after an intervention; and 4) studies were published in peer-reviewed journals written in English.

EVIDENCE SYNTHESIS

A total of 207 studies were observed at the initial search and 73 effect sizes (ESs) were derived from the 34 selected studies. The overall exercise intervention effect was large (Cohen's d [ES]=-1.003, 95% CI=-1.114, -0.892). Moderator analyses results showed that gender (Qb=8.23, df=2, P=0.016), exercise type (Qb=10.68, df=2, P=0.005), and intervention length (Qb=24.71, df=2, P<0.001) influenced the overall ES.

CONCLUSIONS

The group of both boys and girls (ES=-0.95) who participated combined exercise program (Aerobic + Resistance training; ES=-1.17) for 12 months (ES=-1.24) appeared to be the most effective exercise strategy for reducing visceral fat in obese youth.

Carbohydrate-Restriction with High-Intensity Interval Training: An Optimal Combination for Treating Metabolic Diseases?

Lifestyle interventions incorporating both diet and exercise strategies remain cornerstone therapies for treating metabolic disease. Carbohydrate-restriction and high-intensity interval training (HIIT) have independently been shown to improve cardiovascular and metabolic health. Carbohydrate-restriction reduces postprandial hyperglycemia, thereby limiting potential deleterious metabolic and cardiovascular consequences of excessive glucose excursions. Additionally, carbohydrate-restriction has been shown to improve body composition and blood lipids. The benefits of exercise for improving insulin sensitivity are well known. In this regard, HIIT has been shown to rapidly improve glucose control, endothelial function, and cardiorespiratory fitness. Here, we report the available evidence for each strategy and speculate that the combination of carbohydrate-restriction and HIIT will synergistically maximize the benefits of both approaches. We hypothesize that this lifestyle strategy represents an optimal intervention to treat metabolic disease; however, further research is warranted in order to harness the potential benefits of carbohydrate-restriction and HIIT for improving cardiometabolic health.

Can metabolic function and physical fitness improve without weight loss for inactive, obese, Hispanic adolescents? A feasibility study

INTRODUCTION

A case series that examines the effects of a 12-week combined resistance and aerobic training program for four sedentary obese, Hispanic adolescents without weight loss.

SUBJECTS/METHODS

Baseline and post-intervention anthropometric, metabolic and physical fitness measures were obtained. Body composition, hepatic, visceral, and intramuscular fat contents were analyzed via imaging. Fasting levels of alanine transaminase (ALT), insulin, glucose, free fatty acids, triglycerides, high- and low-density lipoproteins (LDL), and C-reactive protein were obtained via blood samples.

RESULTS

Two subjects decreased their glucose levels by 1.86% and 4.06%. Subjects 1, 3, and 4 increased their lean body mass by 4.12%, 9.70%, and 5.48%. ALT was reduced 13.0%, 16.0%, and 35.7% for subjects 2, 3, and 4, respectively. LDLs were reduced by 37.7%, 4.5%, and 7.5% for subjects 1, 2, and 3. Triglycerides were reduced by 25.4%, 37.8%, and 4.6% for subjects 1, 2, and 3. Visceral fat reductions by 16.5%, 14.2%, and 13.0% occurred for subjects 1, 2, and 3. C-reactive protein was reduced for subjects 1, 2, and 3 by 19.4%, 16.3%, and 32.0%.

CONCLUSION

Expected directions of change were made for most indicators of metabolic function and body composition, but measures of physical fitness improved for all four subjects.

A systematic review and meta-analysis on the effects of exercise training versus hypocaloric diet: distinct effects on body weight and visceral adipose tissue

Exercise training ('exercise') and hypocaloric diet ('diet') are frequently prescribed for weight loss in obesity. Whilst body weight changes are commonly used to evaluate lifestyle interventions, visceral adiposity (VAT) is a more relevant and stronger predictor for morbidity and mortality. A meta-analysis was performed to assess the effects of exercise or diet on VAT (quantified by radiographic imaging). Relevant databases were searched through May 2014. One hundred seventeen studies (n = 4,815) were included. We found that both exercise and diet cause VAT loss (P < 0.0001). When comparing diet versus training, diet caused a larger weight loss (P = 0.04). In contrast, a trend was observed towards a larger VAT decrease in exercise (P = 0.08). Changes in weight and VAT showed a strong correlation after diet (R(2)  = 0.737, P < 0.001), and a modest correlation after exercise (R(2)  = 0.451, P < 0.001). In the absence of weight loss, exercise is related to 6.1% decrease in VAT, whilst diet showed virtually no change (1.1%). In conclusion, both exercise and diet reduce VAT. Despite a larger effect of diet on total body weight loss, exercise tends to have superior effects in reducing VAT. Finally, total body weight loss does not necessarily reflect changes in VAT and may represent a poor marker when evaluating benefits of lifestyle-interventions.

Effects of a weight loss program on body composition and the metabolic profile in obese postmenopausal women displaying various obesity phenotypes: a MONET group study

Obesity is a heterogeneous condition, since the metabolic profile may differ greatly from one individual to another. The objective of this study was to compare the effect of a 6-month diet-induced weight loss program on body composition and the metabolic profile in obese individuals displaying different obesity phenotypes. Secondary analyses were done on 129 obese (% body fat: 46% ± 4%) postmenopausal women (age: 57 ± 4 years). Outcome measures included body composition, body fat distribution, glucose homeostasis, fasting lipids, and blood pressure. Obesity phenotypes were determined based on lean body mass (LBM) index (LBMI = LBM/height2) and visceral fat (VF) accumulation, as follows: 1, lower VF and lower LBMI (n = 35); 2, lower VF and higher LBMI (n = 19); 3, higher VF and lower LBMI (n = 14); and 4, higher VF and higher LBMI (n = 61). All groups had significantly improved measures of body composition after the intervention (P < 0.0001). Greater decreases in LBM and LBMI were observed in the higher LBMI groups than in the lower LBMI groups (P < 0.0001). Similarly, decreases in VF were greater in the higher VF groups than in the lower VF groups (P < 0.05). Overall, fasting insulin levels and glucose disposal improved following the intervention, with higher LBMI groups showing a trend for greater improvements (P = 0.06 and 0.07, respectively). Overall, no difference was observed among the different obesity phenotypes regarding improvements in the metabolic profile in response to weight loss. Individuals displaying higher VF or higher LBMI at baseline experienced significantly greater decreases for these variables after the intervention.

Aerobic exercise attenuates the loss of skeletal muscle during energy restriction in adults with visceral adiposity

OBJECTIVE

To evaluate the effects of energy restriction with or without aerobic exercise on thigh muscle mass and quality in adults with visceral adiposity.

METHODS

75 males and females were randomly assigned to the groups 'diet only' (DO; n = 42) or 'diet plus aerobic exercise' (D/Ex; n = 33) for 12 weeks. The target energy intake in both groups was 25 kcal/kg of ideal body weight. Subjects in the D/Ex group were instructed to exercise for ≥300 min/week at lactate threshold. Computed tomography was used to measure thigh muscle cross-sectional area (CSA), normal-density muscle area (NDMA), and visceral fat area.

RESULTS

Total body weight (DO: -6.6 ± 3.6%; D/Ex: -7.3 ± 4.6%) and visceral fat (DO: -16.0 ± 13.8%; D/Ex: -23.1 ± 14.7%) decreased significantly in both groups; however, the changes were not significantly different between the two groups. The decrease in muscle CSA was significantly greater in the DO group (-5.1 ± 4.5%) compared with the D/Ex group (-2.5 ± 5.0%). NDMA decreased significantly in the DO (-4.9 ± 4.9%) but not in the D/Ex group (-1.4 ± 5.0%).

CONCLUSION

Aerobic exercise attenuated the loss of skeletal muscle during energy restriction in adults with visceral adiposity.

Lifestyle intervention involving calorie restriction with or without aerobic exercise training improves liver fat in adults with visceral adiposity

OBJECTIVE

To evaluate the effect of calorie restriction-induced weight loss with or without aerobic exercise on liver fat.

METHODS

Thirty-three adults with visceral adiposity were divided into calorie restriction (CR; n = 18) or CR and aerobic exercise (CR + Ex; n = 15) groups. Target energy intake was 25 kcal/kg of ideal body weight. The CR + Ex group had a targeted exercise time of 300 min/wk or more at lactate threshold intensity for 12 weeks.

RESULTS

Reductions in body weight (CR, -5.3 ± 0.8 kg; CR + Ex, -5.1 ± 0.7 kg), fat mass (CR, -4.9 ± 0.9 kg; CR + Ex, -4.4 ± 0.6 kg), and visceral fat (CR, -24 ± 5 cm2; CR + Ex, -37 ± 5 cm2) were not statistically different between groups. Liver fat decreased significantly in both groups, with no difference between groups. Change in maximal oxygen uptake was significantly greater in the CR + Ex group than in the CR group (CR, -0.7 ± 0.7 mL/kg/min; CR + Ex, 2.9 ± 1.0 mL/kg/min).

CONCLUSION

Both CR and CR + Ex resulted in an improved reduction in liver fat; however, there was no additive effect of exercise training.

Comparison of intragastric balloon therapy and intensive lifestyle modification therapy with respect to weight reduction and abdominal fat distribution in super-obese Japanese patients

This study compared the impacts of intragastric balloon (IGB) therapy and intensive lifestyle modification therapy on abdominal fat distribution. Sixteen extremely obese Japanese patients were assigned to an intensive lifestyle modification therapy group with educational hospitalisation (8 patients) or an IGB therapy group (8 patients) and were followed up for 6 months. The main outcome measures were the differences at 6 months, relative to the baseline values, in the visceral fat area (VFA), subcutaneous fat area (SFA), and liver volume as measured using computed tomography. At 0 month, the body weights (BWs) were 121.3±19.0 kg and 127.1±24.4 kg and the VFAs were 299±55 cm2 and 257±56 cm2 in the intensive lifestyle modification therapy group and the IGB therapy group, respectively. No statistically significant differences in the baseline characteristics were observed between these two groups. At 6 months, no difference in the changes in BW from the baseline value (-11.5 [-16.4, -6.6] kg vs. -11.2 [-18.9, -3.4] kg) was seen between the two groups. However, a statistically significant difference in the change in the VFA (-66 [-87, -44] cm2 vs. -22 [-70, 26]cm(2) [P=0.027]) was observed; no significant changes in the SFA or liver volume were seen. In conclusion, IGB therapy was as effective as intensive lifestyle modification therapy for weight reduction but was less effective with respect to the improvement in abdominal visceral fat accumulation and liver steatosis in super-obese Japanese patients.

The effect of exercise on visceral adipose tissue in overweight adults: a systematic review and meta-analysis

Excessive visceral adipose tissue appears to trigger a cascade of metabolic disturbances that seem to coexist with ectopic fat storage in muscle, liver, heart and the ß-cell. Therefore, the reduction of visceral adipose tissue potentially plays a pivotal role in the treatment of the metabolic syndrome. The purpose of this systematic review and meta-analysis is to describe the overall effect of exercise on visceral adipose tissue and to provide an overview of the effect of different exercise regimes, without caloric restriction, on visceral adipose tissue in obese persons. A systematic literature search was performed according to the PRISMA statement for reporting systematic reviews and meta-analyses. The initial search resulted in 87 articles after removing duplicates. After screening on title, abstract and full-text 15 articles (totalling 852 subjects) fulfilled the a priori inclusion criteria. The quality of each eligible study was assessed in duplicate with “The Critical Review Form for Quantitative Studies”. Using random-effects weights, the standardized mean difference (Hedge's g) of the change in visceral adipose tissue was −0.497 with a 95% confidence interval of −0.655 to −0.340. The Z-value was −6.183 and the p-value (two tailed) was <0.001. A subgroup analysis was performed based on gender, type of training and intensity. Aerobic training of moderate or high intensity has the highest potential to reduce visceral adipose tissue in overweight males and females. These results suggest that an aerobic exercise program, without hypocaloric diet, can show beneficial effects to reduce visceral adipose tissue with more than 30 cm² (on CT analysis) in women and more than 40 cm² in men, even after 12 weeks.

Cigarette smoking increases abdominal and visceral obesity but not overall fatness: an observational study

Background

Cigarette smoking and obesity are leading public health concerns. Both increase the risk for cardiovascular disease, cancer, and metabolic abnormalities. This study was conducted to assess the association between cigarette smoking and different types of obesity.

Methodology/Principal Findings

Two hundred eighty-three visitors to university hospitals located in four main provinces of South Korea were participated. All participants were classified as either current/past or never smokers and were divided into quartiles according to the total pack-years. Body mass index, waist circumference, total body fat percentage, and area of visceral and abdominal subcutaneous fat were measured. These results of each groups were compared. Waist circumference, and visceral fat area showed a J- or U-shaped association with total smoking amount during a lifetime. After restricting the analyses to past/current smokers, we found significant dose-dependent associations of smoking pack-years with abdominal and visceral obesity. Overall obesity measured by body mass index and total body fat percentage did not show such associations. Although current smokers clearly showed significant associations, we could not demonstrate these in past smokers, possibly because of the limited sample size.

Conclusions/Significance

Although smokers did not show significant difference in mean body mass index than those who never smoked, they showed more metabolically adverse fat distributions with increasing smoking amounts. This finding suggests that smoking is not beneficial for weight control. Therefore, smoking cessation and avoidance of smoking commencement should be addressed as important public health issues in preventing obesity and related complications.

Association between Abdominal Fat (DXA) and Its Subcomponents (CT Scan) before and after Weight Loss in Obese Postmenopausal Women: A MONET Study

Introduction. Subcutaneous fat (ScF) and visceral fat (VF) measurements using CT scan are expensive and may imply significant radiation doses. Cross-sectional studies using CT scan showed that ScF and VF are significantly correlated with abdominal fat measured by DXA (AF-DXA). The association has not been studied after a weight loss. Objective. To determine (1) the associations between AF-DXA and ScF and VF before and after weight loss and (2) the associations between their changes. Methods. 137 overweight/obese postmenopausal women were divided in two groups (1-caloric restriction or 2-caloric restriction + resistance training). AF was assessed using DXA and CT scan. Results. Correlations between AF-DXA and ScF (before: r = 0.87, after; r = 0.87; P < .01) and, AF-DXA and VF (before: r = 0.61, after; r = 0.69; P < .01) are not different before and after the weight loss. Correlations between delta AF-DXA and delta ScF (r = 0.72; P < .01) or delta VF (r = 0.51; P < .01) were found. Conclusion. The use of AF-DXA as a surrogate for VF after weight loss is questionable, but may be interesting for ScF.

An increase in high-density lipoprotein cholesterol after weight loss intervention is associated with long-term maintenance of reduced visceral abdominal fat

OBJECTIVES

It is generally agreed that excess abdominal fat, in particular visceral abdominal fat (VAF), is related to an increased risk for obesity-related complications. We examined the association between metabolic risk factors and maintaining VAF after weight loss intervention.

METHODS

A total of 54 postmenopausal, obese women who achieved a VAF loss of at least 10% from their baseline values during a 14-week intervention were enrolled as subjects. Body weight, VAF assessed by CT scans, and metabolic risk factors (that is, blood pressure, lipids and glucose) were measured at baseline (week 0), post-intervention (week 15), and at a 2-year follow-up (week 105). The subjects were divided into two groups according to their changes in VAF between weeks 15 and 105 (follow-up period): (1) VAF gainers (VAF changes > 0 cm², n=28) or (2) VAF maintainers (VAF changes ≤ 0 cm², n=26).

RESULTS

The mean change in VAF of all subjects during the 14-week intervention was -34±16 cm² (-29.7±12.3%) (P<0.01). Along with this change, improvements (P<0.05) were observed in all metabolic risk factors except for high-density lipoprotein cholesterol (HDLC). During the follow-up period, there were interactions between the two VAF groups in HDLC, triglycerides (TG) and total cholesterol (TC)/HDLC ratio (all P<0.01). In particular, the HDLC of VAF maintainers improved, and the value at week 105 exceeded baseline level (P<0.01). However, systolic and diastolic blood pressure, TC and low-density lipoprotein cholesterol in the VAF maintainers increased (all P<0.05) back to their mean baseline level despite a further decrease in their VAF during the follow-up period (P<0.01).

CONCLUSIONS

This study shows that long-term maintenance of VAF after weight loss intervention is associated with improvements in HDLC and TG among obese, postmenopausal women.

Effect of long-term whole body vibration training on visceral adipose tissue: a preliminary report

AIM

To determine the effect of whole body vibration (WBV), combined with caloric restriction, on weight, body composition and metabolic risk factors in overweight and obese adults.

METHODS

A randomized, controlled study with a 6-month intervention period and a 6-month 'no intervention' follow-up. 61 of the 79 participants completed the study. Data were collected at baseline and at 3, 6 and 12 months in the control group (CONTROL), the diet only group (DIET), the diet plus fitness group (FITNESS) and the diet plus WBV group (VIBRATION).

RESULTS

Weight decreased significantly in all three intervention groups. Only FITNESS and VIBRATION managed to maintain a weight loss of 5% or more in the long term. Visceral adipose tissue (VAT) changed most in VIBRATION: -47.8 +/- 41.2 and -47.7 +/- 45.7 cm2 after 6 and 12 months respectively compared to CONTROL (-3.6 +/- 20.5 or +26.3 +/- 30.6 cm(2)), DIET (-24.3 +/- 29.8 or -7.5 +/- 28.3 cm(2)) and FITNESS (-17.6 +/- 36.6 or -1.6 +/- 33.3 cm(2)) (p < 0.001).

CONCLUSIONS

Combining aerobic exercise or WBV training with caloric restriction can help to achieve a sustained long-term weight loss of 5-10%. These preliminary data show that WBV training may have the potential to reduce VAT more than aerobic exercise in obese adults, possibly making it a meaningful addition to future weight loss programs.

Comparison of epicardial, abdominal and regional fat compartments in response to weight loss

BACKGROUND AND AIMS

Echocardiographic measurement of epicardial fat (EF) seems to be a reliable and diagnostic marker of visceral adipose tissue (VAT). However, the weight loss-induced changes in EF have not been compared with those in VAT or the truncal depot. In this study, we aimed to compare the weight loss-induced changes in EF, VAT and other regional fat compartments in obese men.

METHODS AND RESULTS

In this study, 27 moderately obese men (age 45.8+/-1.7 years; body mass index 30.5+/-0.7 kg/m(2)) followed a daily low-calorie diet as part of a clinical 12-week weight loss interventional study. We evaluated the EF thickness by transthoracic echocardiography, assessed the abdominal fat tissues by computed tomography scans, and examined the regional and whole body fat compartments by dual X-ray absorptiometry. An average decrease of 26.8% in the initial calorie intake corresponded to post-program reductions of 17.2%, 11.0%, 16.6%, and 29.8% in EF thickness (P<0.001), body mass, percentage fat mass, and abdominal fat compartments, respectively. The percentage change in VAT in response to weight loss was twice as high as the substantial change in EF tissue (P<0.001).

CONCLUSION

The results of the study suggest that a low-calorie diet-induced weight loss decreases EF thickness. Moderate diet-induced weight loss alone may represent an effective nonpharmacological strategy for reducing EF, which is a unique, pathogenic fat depot and an emerging marker of VAT.

Obesity phenotype and intra-abdominal fat responses to regular aerobic exercise

AIM

To examine the effects of obesity phenotype on abdominal fat responses to regular aerobic exercise.

METHOD

Fifty-seven obese men aged 34-70 years were divided into two groups based on baseline intra-abdominal fat (IF) area measured by computerized tomography: moderate (<200 cm(2)) IF (MIF; n=33, age: 52.9+/-10.6 [SD] yr, body mass index [BMI]: 29.2+/-3.1 kg/m(2)) or high (>or=200 cm(2)) IF (HIF; n=24, age: 53.5+/-9.5 yr, BMI: 30.3+/-3.1 kg/m(2)). The 12-week exercise program consisted primarily of aerobic exercise and met 3 days per week for 90 min per session. Weight, BMI, body composition (by dual-energy X-ray absorptiometry), IF and subcutaneous fat (SF) areas were measured before and after the program.

RESULTS

Regular aerobic exercise reduced weight by 2.3+/-2.2 kg in MIF and 3.2+/-3.0 kg in HIF. HIF reduced significantly more IF area than MIF (15.1+/-26.0 cm(2) in MIF and 43.3+/-41.9 cm(2) in HIF), and the difference remained significant after adjusting for baseline fat mass, weight change and total energy intake during the 12-week aerobic exercise.

CONCLUSION

Exercise-induced IF reduction may be remarkably influenced by obesity phenotype.

Comparable reduction of the visceral adipose tissue depot after a diet-induced weight loss with or without aerobic exercise in obese subjects: a 12-week randomized intervention study

OBJECTIVE

Weight loss with preferential effect on the visceral adipose tissue (VAT) depot could have important clinical benefits. In this study, we investigated the independent and combined effect of regular exercise and diet induced weight loss on body fat distribution. DESIGN; Randomized control design of i) exercise-only (EXO; 12 weeks of exercise without diet-restriction), ii) hypocaloric-diet (DIO; 8 weeks of very low energy diet (VLED 600 kcal/day) followed by 4-weeks weight maintenance diet) and iii) hypocaloric-diet and exercise (DEX; 8 weeks VLED 800 kcal/day+a 4-week weight maintenance diet combined with exercise throughout the 12 weeks).

SUBJECTS

Seventy-nine obese males and females were included.

MEASUREMENTS

Body fat distribution was quantified by magnetic resonance imaging (MRI)-technology.

RESULTS

In the EXO group, the weight loss (3.5 kg) and the relative reduction in VAT (18%) was significantly lower compared with the weight losses in the DIO and DEX groups (12.3 kg; P<0.01) and to the reduction in VAT (30-37%; P<0.01). In all the three groups, the relative reduction of VAT was higher as compared with the reduction in fat mass (FM; combining all fat depots determined by MRI; P<0.01 for all comparisons). The changes in VAT were associated with changes in FM and related to the initial VAT/FM ratio (r(2)=0.72; P<0.01).

CONCLUSION

Exercise has no additional effects in reduction of the VAT depot, compared with the major effects of hypocaloric diet alone. In addition, the effects of exercise per se on VAT are relatively limited. The effects on the VAT depot are closely associated with changes in total FM.

Effect of exercise intensity on abdominal fat loss during calorie restriction in overweight and obese postmenopausal women: a randomized, controlled trial

BACKGROUND

Exercise intensity may affect the selective loss of abdominal adipose tissue.

OBJECTIVE

This study showed whether aerobic exercise intensity affects the loss of abdominal fat and improvement in cardiovascular disease risk factors under conditions of equal energy deficit in women with abdominal obesity.

DESIGN

This was a randomized trial in 112 overweight and obese [body mass index (in kg/m(2)): 25-40; waist circumference >88 cm], postmenopausal women assigned to one of three 20-wk interventions of equal energy deficit: calorie restriction (CR only), CR plus moderate-intensity aerobic exercise (CR + moderate-intensity), or CR plus vigorous-intensity exercise (CR + vigorous-intensity). The diet was a controlled program of underfeeding during which meals were provided at individual calorie levels (approximately 400 kcal/d). Exercise (3 d/wk) involved treadmill walking at an intensity of 45-50% (moderate-intensity) or 70-75% (vigorous-intensity) of heart rate reserve. The primary outcome was abdominal visceral fat volume.

RESULTS

Average weight loss for the 95 women who completed the study was 12.1 kg (+/-4.5 kg) and was not significantly different across groups. Maximal oxygen uptake ( O(2)max) increased more in the CR + vigorous-intensity group than in either of the other groups (P < 0.05). The CR-only group lost relatively more lean mass than did either exercise group (P < 0.05). All groups showed similar decreases in abdominal visceral fat (approximately 25%; P < 0.001 for all). However, changes in visceral fat were inversely related to increases in O(2)max (P < 0.01). Changes in lipids, fasting glucose or insulin, and 2-h glucose and insulin areas during the oral-glucose-tolerance test were similar across treatment groups.

CONCLUSION

With a similar amount of total weight loss, lean mass is preserved, but there is not a preferential loss of abdominal fat when either moderate- or vigorous-intensity aerobic exercise is performed during caloric restriction. This trial was registered at (ClinicalTrials.gov) as: NCT00664729.

Cost-sparing effect of twice-weekly targeted endurance training in type 2 diabetics: a one-year controlled randomized trial

OBJECTIVE

We evaluated the effects of targeted, moderate endurance training on healthcare cost, body composition and fitness in type 2 diabetes patients routinely followed within the French healthcare system.

DESIGN AND METHODS

A total of 25 type 2 diabetic patients was randomly assigned to one of two groups: 13 underwent a training programme (eight sessions, followed by training twice a week for 30-45 minutes at home at the level of the ventilatory threshold [V(T)]); and 12 received their usual routine treatment. Both groups were followed for one year to evaluate healthcare costs, exercise effectiveness and a six-minute walking test.

RESULTS

The training prevented loss of maximum aerobic capacity, which decreased slightly in the untrained group (P=0.014), and resulted in a higher maximum power output (P=0.041) and six-minute walking distance (P=0.020). The Voorrips activity score correlated with both V(O2max) (r=0.422, P<0.05) and six-minute walking distance (r=0.446, P<0.05). Changes in V(O2max) were negatively correlated with changes in body weight (r=0.608, P<0.01). Training decreased the insulin-resistance index (HOMA-IR) by 26% (P<0.05). Changes in percentages of fat were correlated to changes in waist circumference (r=0.436, P<0.05). The total healthcare cost was reduced by 50% in the trained group (euro 1.65+/-1 per day versus euro 3.00+/-1.47 per day in the untrained group; P<0.02) due to fewer hospitalizations (P=0.05) and less use of sulphonylureas (P<0.05).

CONCLUSION

Endurance training at V(T) level prevented the decline in aerobic working capacity seen in untrained diabetics over the study period, and resulted in a marked reduction in healthcare costs due to less treatments and fewer hospitalizations.

Factors associated with percent change in visceral versus subcutaneous abdominal fat during weight loss: findings from a systematic review

BACKGROUND

Visceral adipose tissue (VAT) is associated with greater obesity-related metabolic disturbance. Many studies have reported preferential loss of VAT with weight loss.

OBJECTIVE

This systematic review looks for factors associated with preferential loss of VAT relative to subcutaneous abdominal fat (SAT) during weight loss.

DESIGN

Medline and Embase were searched for imaging-based measurements of VAT and subcutaneous abdominal adipose tissue (SAT) before and after weight loss interventions. We examine for factors that influences the percentage change in VAT versus SAT (%deltaV/%deltaS) with weight loss. Linear regression analyses were performed on the complete data set and on subgroups of studies. Factors examined included percentage weight loss, degree of caloric restriction, exercise, initial body mass index (BMI), gender, time of follow-up and baseline VAT/SAT.

RESULTS

There were 61 studies with a total of 98 cohort time points extracted. Percentage weight loss was the only variable that influenced %deltaV/%deltaS (r=-0.29, P=0.005). Modest weight loss generated preferential loss of VAT, but with greater weight loss this effect was attenuated. The method of weight loss was not an influence with one exception. Very-low-calorie diets (VLCDs) provided exceptional short-term (<4 weeks) preferential VAT loss. But this effect was lost by 12-14 weeks.

CONCLUSIONS

Visceral adipose tissue is lost preferentially with modest weight loss, but the effect is attenuated with greater weight loss. Acute caloric restriction, using VLCD, produces early preferential loss of VAT. These observations may help to explain the metabolic benefits of modest weight loss.

Regional body composition in college-aged Caucasians from anthropometric measures

BACKGROUND

Quantitating fat and lean tissue in isolated body regions may be helpful or required in obesity and health-outcomes research. However, current methods of regional body composition measurement require specialized, expensive equipment such as that used in computed tomography or dual energy x-ray absorptiometry (DEXA). Simple body size or circumference measurement relationships to body composition have been developed but are limited to whole-body applications. We investigated relationships between body size measurements and regional body composition.

METHODS

Using DEXA technology we determined the fat and lean tissue composition for six regions of the body in predominantly Caucasian, college-aged men (n = 32) and women (n = 67). Circumference measurements as well as body weight and height were taken for each individual. Equations relating body measurements to a respective regional fat and lean mass were developed using multiple regression analysis.

RESULTS

Multiple regression R2 values ranged from 0.4451 to 0.8953 and 0.1697 to 0.7039 for regional fat and lean mass relationships to body measurements, respectively.

CONCLUSION

The equations developed in this study offer a simple way of estimating regional body composition in a college-aged adult population. The parameters used in the equations are common body measurements that can be obtained with the use of a measuring tape and weight scale.

Effects of aerobic exercise on metabolic syndrome improvement in response to weight reduction

OBJECTIVE

The objective was to test effects of aerobic exercise training on metabolic syndrome (MetSyn) improvement in response to weight reduction.

RESEARCH METHODS AND PROCEDURES

A total of 459 overweight and obese women (age, 49 +/- 9 years; BMI, 28 +/- 3 kg/m(2)) were recruited for a baseline examination to test the relationship between cardiorespiratory fitness and metabolic syndrome prevalence; among these, 67 subjects with MetSyn were treated with 14-week weight-loss programs, which included low-calorie diet and aerobic exercise. The MetSyn was defined according to the Examination Committee of Criteria for "Metabolic Syndrome" in Japan. Maximal oxygen uptake (Vo(2max)) during a maximal cycling test was measured as an index of cardiorespiratory fitness at baseline and after the intervention.

RESULTS

In the baseline examination, age- and BMI-adjusted odds ratios for MetSyn prevalence in the low, middle, and upper thirds of Vo(2max) were 1.0 (referent), 0.50 (95% confidence interval, 0.26 to 0.95), and 0.39 (95% confidence interval, 0.14 to 0.96), respectively (linear trend, p = 0.02). The adjusted odds ratios for MetSyn improvement in the two interventions with diet alone and diet plus exercise were 1.0 and 3.68 (95% confidence interval, 1.02 to 17.6; p = 0.04), respectively.

DISCUSSION

These results suggest that adding aerobic exercise training to a dietary weight-reduction program further improves MetSyn (adjusted odds ratio, 3.68) in obese women, compared with diet alone. Further studies on an association between Vo(2max) change and MetSyn improvement are needed.

Effect of calorie restriction with or without exercise on insulin sensitivity, beta-cell function, fat cell size, and ectopic lipid in overweight subjects

OBJECTIVE

The purpose of this article was to determine the relationships among total body fat, visceral adipose tissue (VAT), fat cell size (FCS), ectopic fat deposition in liver (intrahepatic lipid [IHL]) and muscle (intramyocellular lipid [IMCL]), and insulin sensitivity index (S(i)) in healthy overweight, glucose-tolerant subjects and the effects of calorie restriction by diet alone or in conjunction with exercise on these variables.

RESEARCH DESIGN AND METHODS

Forty-eight overweight volunteers were randomly assigned to four groups: control (100% of energy requirements), 25% calorie restriction (CR), 12.5% calorie restriction +12.5% energy expenditure through structured exercise (CREX), or 15% weight loss by a low-calorie diet followed by weight maintenance for 6 months (LCD). Weight, percent body fat, VAT, IMCL, IHL, FCS, and S(i) were assessed at baseline and month 6.

RESULTS

At baseline, FCS was related to VAT and IHL (P < 0.05) but not to IMCL. FCS was also the strongest determinant of S(i) (P < 0.01). Weight loss at month 6 was 1 +/- 1% (control, mean +/- SE), 10 +/- 1% (CR), 10 +/- 1% (CREX), and 14 +/- 1% (LCD). VAT, FCS, percent body fat, and IHL were reduced in the three intervention groups (P < 0.01), but IMCL was unchanged. S(i) was increased at month 6 (P = 0.05) in the CREX (37 +/- 18%) and LCD (70 +/- 34%) groups (P < 0.05) and tended to increase in the CR group (40 +/- 20%, P = 0.08). Together the improvements in S(i) were related to loss in weight, fat mass, and VAT, but not IHL, IMCL, or FCS.

CONCLUSIONS

Large adipocytes lead to lipid deposition in visceral and hepatic tissues, promoting insulin resistance. Calorie restriction by diet alone or with exercise reverses this trend.