Addition of aerobic exercise to dietary weight loss preferentially reduces abdominal adipocyte size

Evolutionary Echoes: A Four-Day Fasting and Low-Caloric Intake Study on Autonomic Modulation and Physiological Adaptations in Humans

This study evaluates the psychophysiological response to a simulated hunter-gatherer endurance task with restricted caloric intake over four days. It assesses changes in body composition, autonomic modulation, and physical and cognitive performance. Participants underwent daily 8 h fasted walks followed by a 150 kcal meal to replicate hunter-gatherer activity and dietary patterns. Measurements of metabolic, respiratory, and subjective well-being, along with heart rate variability (HRV) monitoring, were conducted pre- and post-activity to evaluate the impact of endurance activity under caloric restriction. We found weight loss, decreased body and visceral fat, and reduced skeletal muscle mass and water percentage. High sympathetic activation and stable urinary markers, except for increased proteinuria, indicated stress responses and muscular degradation. Elevated perceived exertion post-exercise with good adaptation to prolonged effort underlines the body's adaptability to ancestral lifestyle conditions, highlighting the connection among endurance, nutrition, and psychophysiological health.

Exercise induces tissue-specific adaptations to enhance cardiometabolic health

The risk associated with multiple cancers, cardiovascular disease, diabetes, and all-cause mortality is decreased in individuals who meet the current recommendations for physical activity. Therefore, regular exercise remains a cornerstone in the prevention and treatment of non-communicable diseases. An acute bout of exercise results in the coordinated interaction between multiple tissues to meet the increased energy demand of exercise. Over time, the associated metabolic stress of each individual exercise bout provides the basis for long-term adaptations across tissues, including the cardiovascular system, skeletal muscle, adipose tissue, liver, pancreas, gut, and brain. Therefore, regular exercise is associated with a plethora of benefits throughout the whole body, including improved cardiorespiratory fitness, physical function, and glycemic control. Overall, we summarize the exercise-induced adaptations that occur within multiple tissues and how they converge to ultimately improve cardiometabolic health.

Promotion of Successful Weight Management in Overweight and Obese Veterans (POWER-VET): Trial Design and Methods

BACKGROUND

Almost 75% of US adults are overweight or obese. Though intentional weight loss of as little as 3% improves physical functioning and reduces cardiometabolic risk, most adults are unsuccessful at long-term weight maintenance. Our hypothesis is that intermittent fasting (IF: short periods of intense energy restriction) will reduce weight regain. IF may combat obesity due to its effects on nutrient-sensing signaling pathways and circadian rhythm. The objective of this randomized clinical trial is to test the effectiveness of an intensive body weight management program with and without IF.

METHODS

In the Promotion of Successful Weight Management in Overweight and Obese Veterans (POWER-VET) trial (NCT04131647), 154 middle-aged and older adults (50-75 years) who are overweight and obese (BMI: 25-40 kg/m2) and seen at either a Baltimore, MD or San Antonio, TX Veterans Affairs Medical Center will be enrolled. Participants will undergo 12 weeks of weight loss (including a low-calorie heart healthy (HH) diet and exercise). Following weight loss, participants will be randomly assigned to one of two 24-week weight maintenance (WM) interventions: WM alone (continuation of HH diet and exercise) or WM + IF. The primary aim is to determine the effect of WM + IF compared to WM alone on body weight maintenance after intentional weight loss.

DISCUSSION

Determining effective, translatable strategies that minimize weight regain following successful weight loss holds public health relevance. This POWER-VET trial introduces an innovative practice of IF to prevent weight regain after clinically significant weight reduction and could provide evidence-based recommendations to promote this type of intervention in middle aged and older adults.

Adipose Tissue Dynamics: Cellular and Lipid Turnover in Health and Disease

The alarming increase in obesity and its related metabolic health complications, such as type 2 diabetes, has evolved into a global pandemic. Obesity is mainly characterized by excessive accumulation of adipose tissue, primarily due to an imbalance between energy intake and expenditure. Prolonged positive energy balance leads to the expansion of existing adipocytes (hypertrophy) and/or an increase in preadipocyte and adipocyte number (hyperplasia) to accommodate excess energy intake. However, obesity is not solely defined by increases in adipocyte size and number. The turnover of adipose tissue cells also plays a crucial role in the development and progression of obesity. Cell turnover encompasses the processes of cell proliferation, differentiation, and apoptosis, which collectively regulate the overall cell population within adipose tissue. Lipid turnover represents another critical factor that influences how adipose tissue stores and releases energy. Our understanding of adipose tissue lipid turnover in humans remains limited due to the slow rate of turnover and methodological constraints. Nonetheless, disturbances in lipid metabolism are strongly associated with altered adipose tissue lipid turnover. In obesity, there is a decreased rate of triglyceride removal (lipolysis followed by oxidation), leading to the accumulation of triglycerides over time. This review provides a comprehensive summary of findings from both in vitro and in vivo methods used to study the turnover of adipose cells and lipids in metabolic health and disease. Understanding the mechanisms underlying cellular and lipid turnover in obesity is essential for developing strategies to mitigate the adverse effects of excess adiposity.

Depot-specific adaption of adipose tissue for different exercise approaches in high-fat diet/streptozocin-induced diabetic mice

Background: Adipose tissue pathology plays a crucial role in the pathogenesis of type 2 diabetes mellitus. Understanding the impact of exercise training on adipose tissue adaptation is of paramount importance in enhancing metabolic health. In this study, we aimed to investigate the effects of various exercise modalities on three distinct adipose tissue depots, namely, interscapular brown adipose tissue (iBAT), subcutaneous white adipose tissue (sWAT), and epididymal white adipose tissue (eWAT), in a murine model of diabetes. Methods: Male C57BL/6J mice received a 12-week high-fat diet and a single injection of streptozotocin, followed by an 8-week exercise intervention. The exercise intervention included swimming, resistance training, aerobic exercise, and high-intensity interval training (HIIT). Results: We found that exercise training reduced body weight and body fat percentage, diminished adipocyte size and increased the expression of mitochondria-related genes (PGC1, COX4, and COX8B) in three adipose tissue depots. The effects of exercise on inflammatory status include a reduction in crown-like structures and the expression of inflammatory factors, mainly in eWAT. Besides, exercise only induces the browning of sWAT, which may be related to the expression of the sympathetic marker tyrosine hydroxylase. Among the four forms of exercise, HIIT was the most effective in reducing body fat percentage, increasing muscle mass and reducing eWAT adipocyte size. The expression of oxidative phosphorylation and thermogenesis-related genes in sWAT and eWAT was highest in the HIIT group. Conclusion: When targeting adipose tissue to improve diabetes, HIIT may offer superior benefits and thus represents a more advantageous choice.

Expression of Adipose Tissue Extracellular Matrix-Related Genes Predicts Weight Loss after Bariatric Surgery

BACKGROUND

We evaluated the association between white adipose tissue parameters before bariatric surgery (BS) and post-surgical weight loss, with an especial focus on extracellular matrix (ECM) gene expression.

METHODS

Paired samples from subcutaneous (SAT) and visceral adipose tissue (VAT) were obtained from 144 subjects undergoing BS. The association between total body weight loss (%TBWL) at 12 months after BS and the histological characteristics and gene expression of selected genes in SAT and VAT was analyzed.

RESULTS

Fat cell area, size-frequency distribution, and fibrosis in SAT or VAT prior to surgery were not associated with %TBWL. On the contrary, the SAT expression of COL5A1 and COL6A3 was associated with %TBWL after BS (both p < 0.001), even after adjusting for age, gender, baseline BMI, and type 2 diabetes status (T2D). Furthermore, in logistic regression analyses, the expression of these genes was significantly associated with insufficient WL (IWL = TBWL < 20%) after BS (respectively, p = 0.030 and p = 0.031). Indeed, in ROC analysis, the prediction of IWL based on sex, age, BMI, T2D, and the type of surgery (AUC = 0.71) was significantly improved with the addition of SAT-COL5A1 gene expression (AUC = 0.88, Z = 2.13, p = 0.032).

CONCLUSIONS

Our data suggest that the expression of SAT ECM-related genes may help explain the variability in TBWL following BS.

Nutrition and exercise interventions to improve body composition for persons with overweight or obesity near retirement age: A systematic review and network meta-analysis of randomised controlled trials

The retirement phase is an opportunity to integrate healthy (nutrition/exercise) habits into daily life. We conducted this systematic review to assess which nutrition and exercise interventions most effectively improve body composition (fat/muscle mass), body mass index (BMI) and waist circumference (WC) in persons with obesity/overweight near retirement age (ages 55-70). We conducted a systematic review and network-meta-analysis (NMA) of randomised controlled trials, searching four databases from their inception up to 12 July 2022. The NMA was based on a random effects model, pooled mean differences, standardised mean differences, their 95% confidence intervals, and correlations with multi-arm studies. Subgroup and sensitivity analyses were also conducted. 92 studies were included, 66 of which with 4957 participants could be used for the NMA. Identified interventions were clustered into 12 groups: no intervention, energy restriction (i.e. 500-1000 kcal), energy restriction plus high protein (HP) intake (1.1-1.7 g/kg/body weight), intermittent fasting, mixed exercise (aerobic and resistance), resistance training (RT), aerobic training (AT), HP plus RT, energy restriction plus HP plus exercise, energy restriction plus RT, energy restriction plus AT, and energy restriction plus mixed exercise (ME). Intervention durations ranged from 8 weeks to 6 months. Body fat was reduced with energy restriction plus any exercise or plus HP intake. Energy restriction alone was less effective and tended to decrease muscle mass. Muscle mass was only significantly increased with ME. All other interventions including exercise effectively preserved muscle mass. A BMI and/or WC decrease was achieved with all interventions except AT/RT alone or RT plus HP. Overall, the most effective strategy for nearly all outcomes was combining energy restriction with RT or ME and HP. Healthcare professionals involved in the management of persons with obesity need to be aware that an energy-restricted diet alone may contribute to sarcopenic obesity in persons near retirement age. This network meta-analysis is registered at https://www.crd.york.ac.uk/prospero/as CRD42021276465.

Fat Cell Size: Measurement Methods, Pathophysiological Origins, and Relationships With Metabolic Dysregulations

The obesity pandemic increasingly causes morbidity and mortality from type 2 diabetes, cardiovascular diseases and many other chronic diseases. Fat cell size (FCS) predicts numerous obesity-related complications such as lipid dysmetabolism, ectopic fat accumulation, insulin resistance, and cardiovascular disorders. Nevertheless, the scarcity of systematic literature reviews on this subject is compounded by the use of different methods by which FCS measurements are determined and reported. In this paper, we provide a systematic review of the current literature on the relationship between adipocyte hypertrophy and obesity-related glucose and lipid dysmetabolism, ectopic fat accumulation, and cardiovascular disorders. We also review the numerous mechanistic origins of adipocyte hypertrophy and its relationship with metabolic dysregulation, including changes in adipogenesis, cell senescence, collagen deposition, systemic inflammation, adipokine secretion, and energy balance. To quantify the effect of different FCS measurement methods, we performed statistical analyses across published data while controlling for body mass index, age, and sex.

Rapid Escalation of High-Volume Exercise during Caloric Restriction; Change in Visceral Adipose Tissue and Adipocytokines in Obese Sedentary Breast Cancer Survivors

Simple Summary

Aerobic exercise reduces risk for developing breast cancer or for breast cancer recurrence. In obese women exercise can significantly augment the effects of caloric restriction on visceral fat, reducing metabolic abnormalities and cancer. Women who are older, obese, and sedentary, especially those who have been treated for breast cancer, find it difficult to initiate and achieve the minimum or optimum levels of exercise. In a two-part pilot we found that by providing older, obese, sedentary breast cancer survivors 12 weeks of twice weekly personal training sessions, they could safely increase exercise to ≥200 min/week by 9 weeks during caloric restriction. At 24 weeks, high levels of exercise were still observed with continued behavioral support and study-provided exercise facility. Substantial improvement in visceral fat and breast cancer risk biomarkers were observed with this affordable intervention that is readily exportable to the community.

Abstract

Aerobic exercise reduces risk for breast cancer and recurrence and promotes visceral adipose tissue (VAT) loss in obesity. However, few breast cancer survivors achieve recommended levels of moderate to vigorous physical activity (MVPA) without supervision. In a two-cohort study, feasibility of 12 weeks of partially supervised exercise was started concomitantly with caloric restriction and effects on body composition and systemic risk biomarkers were explored. In total, 22 obese postmenopausal sedentary women (including 18 breast cancer survivors) with median age of 60 and BMI of 37 kg/m² were enrolled. Using personal trainers twice weekly at area YMCAs, MVPA was escalated to ≥200 min/week over 9 weeks. For cohort 2, maintenance of effect was assessed when study provided trainer services were stopped but monitoring, group counseling sessions, and access to the exercise facility were continued. Median post-escalation MVPA was 219 min/week with median 12-week mass and VAT loss of 8 and 19%. MVPA was associated with VAT loss which was associated with improved adiponectin:leptin ratio. In total, 9/11 of cohort-2 women continued the behavioral intervention for another 12 weeks without trainers. High MVPA continued with median 24-week mass and VAT loss of 12 and 29%. This intervention should be further studied in obese sedentary women.

Putting ATM to BED: How Adipose Tissue Macrophages Are Affected by Bariatric Surgery, Exercise, and Dietary Fatty Acids

With increasing adiposity in obesity, adipose tissue macrophages contribute to adipose tissue malfunction and increased circulating proinflammatory cytokines. The chronic low-grade inflammation that occurs in obesity ultimately gives rise to a state of metainflammation that increases the risk of metabolic disease. To date, only lifestyle and surgical interventions have been shown to be somewhat effective at reversing the negative consequences of obesity and restoring adipose tissue homeostasis. Exercise, dietary interventions, and bariatric surgery result in immunomodulation, and for some individuals their effects are significant with or without weight loss. Robust evidence suggests that these interventions reduce chronic inflammation, in part, by affecting macrophage infiltration and promoting a phenotypic switch from the M1- to M2-like macrophages. The purpose of this review is to discuss the impact of dietary fatty acids, exercise, and bariatric surgery on cellular characteristics affecting adipose tissue macrophage presence and phenotypes in obesity.

Exercise reduced the formation of new adipocytes in the adipose tissue of mice in vivo

Exercise has beneficial effects on metabolism and health. Although the skeletal muscle has been a primary focus, exercise also mediates robust adaptations in white adipose tissue. To determine if exercise affects in vivo adipocyte formation, fifty-two, sixteen-week-old C57BL/6J mice were allowed access to unlocked running wheels [Exercise (EX) group; n = 13 males, n = 13 females] or to locked wheels [Sedentary (SED) group; n = 13 males, n = 13 females] for 4-weeks. In vivo adipocyte formation was assessed by the incorporation of deuterium (²H) into the DNA of newly formed adipocytes in the inguinal and gonadal adipose depots. A two-way ANOVA revealed that exercise significantly decreased new adipocyte formation in the adipose tissue of mice in the EX group relative to the SED group (activity effect; P = 0.02). This reduction was observed in male and female mice (activity effect; P = 0.03). Independent analysis of the depots showed a significant reduction in adipocyte formation in the inguinal (P = 0.05) but not in the gonadal (P = 0.18) of the EX group. We report for the first time that exercise significantly reduced in vivo adipocyte formation in the adipose tissue of EX mice using a physiologic metabolic ²H₂O-labeling protocol.

Influence of Acute and Chronic Exercise on Abdominal Fat Lipolysis: An Update

Exercise is a powerful and effective preventive measure against chronic diseases by increasing energy expenditure and substrate mobilization. Long-duration acute exercise favors lipid mobilization from adipose tissue, i.e., lipolysis, as well as lipid oxidation by skeletal muscles, while chronic endurance exercise improves body composition, facilitates diet-induced weight loss and long-term weight maintenance. Several hormones and factors have been shown to stimulate lipolysis in vitro in isolated adipocytes. Our current knowledge supports the view that catecholamines, atrial natriuretic peptide and insulin are the main physiological stimuli of exercise-induced lipolysis in humans. Emerging evidences indicate that contracting skeletal muscle can release substances capable of remote signaling to organs during exercise. This fascinating crosstalk between skeletal muscle and adipose tissue during exercise is currently challenging our classical view of the physiological control of lipolysis, and provides a conceptual framework to better understand the pleotropic benefits of exercise at the whole-body level.

Exercise Training Reduces Inflammation of Adipose Tissue in the Elderly: Cross-Sectional and Randomized Interventional Trial

CONTEXT

Metabolic disturbances and a pro-inflammatory state associated with aging and obesity may be mitigated by physical activity or nutrition interventions.

OBJECTIVE

The aim of this study is to assess whether physical fitness/exercise training (ET) alleviates inflammation in adipose tissue (AT), particularly in combination with omega-3 supplementation, and whether changes in AT induced by ET can contribute to an improvement of insulin sensitivity and metabolic health in the elderly.

DESIGN, PARTICIPANTS, MAIN OUTCOME MEASURES

The effect of physical fitness was determined in cross-sectional comparison of physically active/physically fit (trained) and sedentary/less physically fit (untrained) older women (71 ± 4 years, n = 48); and in double-blind randomized intervention by 4 months of ET with or without omega-3 (Calanus oil) supplementation (n = 55). Physical fitness was evaluated by spiroergometry (maximum graded exercise test) and senior fitness tests. Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp. Samples of subcutaneous AT were used to analyze mRNA gene expression, cytokine secretion, and immune cell populations.

RESULTS

Trained women had lower mRNA levels of inflammation and oxidative stress markers, lower relative content of CD36+ macrophages, and higher relative content of γδT-cells in AT when compared with untrained women. Similar effects were recapitulated in response to a 4-month ET intervention. Content of CD36+ cells, γδT-cells, and mRNA expression of several inflammatory and oxidative stress markers correlated to insulin sensitivity and cardiorespiratory fitness.

CONCLUSIONS

In older women, physical fitness is associated with less inflammation in AT. This may contribute to beneficial metabolic outcomes achieved by ET. When combined with ET, omega-3 supplementation had no additional beneficial effects on AT inflammatory characteristics.

Response of Mitochondrial Respiration in Adipose Tissue and Muscle to 8 Weeks of Endurance Exercise in Obese Subjects

CONTEXT

Exercise training improves glycemic control and increases mitochondrial content and respiration capacity in skeletal muscle. Rodent studies suggest that training increases mitochondrial respiration in adipose tissue.

OBJECTIVE

To assess the effects of endurance training on respiratory capacities of human skeletal muscle and abdominal subcutaneous adipose tissue and to study the correlation with improvement in insulin sensitivity.

DESIGN

Using high-resolution respirometry, we analyzed biopsies from 25 sedentary (VO2 peak 25.1 ± 4.0 VO2 mL/[kg*min]) subjects (16 female, 9 male; 29.8 ± 8.4 years) with obesity (body mass index [BMI] 31.5 ± 4.3 kg/m2), who did not have diabetes. They performed a supervised endurance training over 8 weeks (3 × 1 hour/week at 80% VO2 peak).

RESULTS

Based on change in insulin sensitivity after intervention (using the Matsuda insulin sensitivity index [ISIMats]), subjects were grouped in subgroups as responders (>15% increase in ISIMats) and low-responders. The response in ISIMats was correlated to a reduction of subcutaneous and visceral adipose tissue volume. Both groups exhibited similar increases in fitness, respiratory capacity, and abundance of mitochondrial enzymes in skeletal muscle fibers. Respiratory capacities in subcutaneous adipose tissue were not altered by the intervention. Compared with muscle fibers, adipose tissue respiration showed a preference for β-oxidation and complex II substrates. Respiratory capacities were higher in adipose tissue from female participants.

CONCLUSION

Our data show that the improvement of peripheral insulin sensitivity after endurance training is not directly related to an increase in mitochondrial respiratory capacities in skeletal muscle and occurs without an increase in the respiratory capacity of subcutaneous adipose tissue.

A Time to Eat and a Time to Exercise

Analogous to exercise training, time-restricted eating may rescue some of the deleterious effects on metabolic health induced by our modern-day lifestyle.

This Perspective for Progress provides a synopsis for the potential of time-restricted eating (TRE) to rescue some of the deleterious effects on circadian biology induced by our modern-day lifestyle. We provide novel insights into the comparative and potential complementary effects of TRE and exercise training on metabolic health.

Effects of a Hypocaloric, Nutritionally Complete, Higher Protein Meal Plan on Regional Body Fat and Cardiometabolic Biomarkers in Older Adults with Obesity

BACKGROUND

Whether improvements in cardiometabolic health following weight loss (WL) are associated with changes in regional body fat distribution (gluteal vs. -android) is not well documented.

METHODS

Older (age: 70 ± 4 years; mean ± SD) adults with obesity were randomized to a 6-month WL program (WL; n = 47), accomplished using a hypocaloric, nutritionally complete, higher protein -(targeting ≥1.0 g/kg/day) meal plan, or a weight stability (WS; n = 49) program. Android, gynoid, visceral, and subcutaneous abdominal fat masses (via dual energy X-ray absorptiometry ) and fasting glucose and lipid profiles were assessed at baseline and 6 months.

RESULTS

The WL group lost more body weight (WL: -8.6% vs. WS: -1.7%, p < 0.01), resulting in a reduction in fat mass at each region only following WL (all p < 0.05). The decline in the ratio of android/gynoid fat mass also was significant only following WL, resulting in greater declines than WS (mean [95% CI]; WL: -0.026 [-0.040 to -0.011] vs. WS: 0.003 [-0.012 to 0.019] g, p < 0.01). The change in the ratio of visceral/subcutaneous abdominal fat mass was not significant in either group and did not differ between groups (WL: 0.65 [-0.38 to 1.68] vs. WS: 0.05 [-1.00 to 1.10] g, p = 0.42). In general, the improvements in glucose and lipid profiles were associated with declines in fat mass at the gynoid and android regions (r's = 0.20-0.42, all p < 0.05), particularly the visceral depot but not the ratios.

CONCLUSION

WL achieved via a hypocaloric, nutritionally complete, higher protein meal plan is effective in reducing body fat in the android, gynoid, and visceral depots, which relate to cardiometabolic improvements.

Adipose cell size: importance in health and disease

Adipose tissue is necessary to harbor energy. To handle excess energy, adipose tissue expands by increasing adipocyte size (hypertrophy) and number (hyperplasia). Here, we have summarized the different experimental techniques used to study adipocyte cell size and describe adipocyte size in relation to insulin resistance, type 2 diabetes, and diet interventions. Hypertrophic adipocytes have an impaired cellular function, and inherent mechanisms restrict their expansion to protect against cell breakage and subsequent inflammation. Reduction of large fat cells by diet restriction, physical activity, or bariatric surgery therefore is necessary to improve cellular function and health. Small fat cells may also be dysfunctional and unable to expand. The distribution and function of the entire cell size range of fat cells, from small to very large fat cells, are an important but understudied aspect of adipose tissue biology. To prevent dysmetabolism, therapeutic strategies to expand small fat cells, recruit new fat cells, and reduce large fat cells are needed.

Effects of Weight Loss with and without Exercise on Regional Body Fat Distribution in Postmenopausal Women

BACKGROUND/AIMS

The purpose was to determine whether lifestyle interventions have different effects on regional fat in women with normal glucose tolerance vs. impaired glucose tolerance (NGT vs. IGT).

METHODS

Changes in glucose metabolism (2-h oral glucose-tolerance tests), android to gynoid fat mass ratio (dual energy X-ray absorptiometry [DXA]), visceral to subcutaneous abdominal fat area ratio (CT), and abdominal to gluteal subcutaneous fat cell weight (FCW; adipose tissue biopsies) were determined in 60 overweight postmenopausal women (45-80 years) following 6 months of weight loss alone (WL; n = 28) or with aerobic exercise (AEX + WL; n = 32).

RESULTS

The interventions led to ∼8% decrease in weight, but only the AEX + WL group improved fitness (↑11% in VO2max) and reduced the android-to-gynoid fat mass ratio (↓5%; p < 0.05). Both NGT and IGT groups reduced visceral and subcutaneous abdominal fat areas and abdominal and gluteal FCWs, which related to improvements in homeostatic model assessment (r = 0.34-0.42) and 2-h glucose (r = 0.34-0.35), respectively (p < 0.05). The decline in FCW was 2× greater in women with IGT following WL (p < 0.05). The ratios of abdominal-to-gluteal FCW did not change following either intervention.

CONCLUSIONS

The mechanisms by which WL with and without exercise impact regional fat loss should be explored as reductions in abdominal fat area and subcutaneous FCW appear to influence glucose metabolism. This is a work of the U.S. Government and is not subject to copyright protection in the United States. Foreign copyrights may apply. Published by S. Karger AG, Basel.

Factors associated with adipocyte size reduction after weight loss interventions for overweight and obesity: a systematic review and meta-regression

AIMS

Enlarged adipocytes are a prime feature of adipose tissue dysfunction, and may be an appropriate target to decrease disease risk in obesity. We aimed to assess the change in adipocyte size in response to lifestyle and surgical weight loss interventions for overweight or obesity; and to explore whether certain participant and intervention characteristics influence this response.

METHODS

We systematically searched MEDLINE, EMBASE, CINAHL and Cochrane electronic databases to identify weight loss studies that quantified adipocyte size before and after the intervention. Using meta-regression analysis, we assessed the independent effects of weight loss, age, sex, adipocyte region, and intervention type (surgical vs. lifestyle) on adipocyte size reduction. We repeated the model as a sensitivity analysis including only the lifestyle interventions.

RESULTS

Thirty-five studies met our eligibility criteria. In our main model, every 1.0% weight loss was associated with a 0.64% reduction in adipocyte size (p=0.003); and adipocytes from the upper body decreased 5% more in size than those in the lower body (p=0.009). These relationships were no longer significant when focusing only on lifestyle interventions. Moreover, age, sex and intervention type did not independently affect adipocyte size reduction in either model.

CONCLUSIONS

Weight loss in obese individuals is consistently associated with a decrease in adipocyte size that is more pronounced in upper-body adipocytes. It remains to be clarified how biological differences and intervention characteristics influence this relationship, and whether it corresponds with reductions in other aspects of adipose tissue dysfunction and disease risk.

Addition of Exercise Increases Plasma Adiponectin and Release from Adipose Tissue

INTRODUCTION

Adiponectin is an adipose tissue-derived anti-inflammatory protein that is down-regulated in obesity. The effects of caloric restriction and exercise-induced weight loss on adiponectin are not clear.

PURPOSE

To determine whether addition of aerobic exercise training to caloric restriction has additive effects over caloric restriction alone on circulating adiponectin concentrations and adiponectin release from abdominal and gluteal adipose tissue.

METHODS

Overweight or obese (body mass index, 25-40 kg·m(-2); waist >88 cm) postmenopausal women were randomized to 20-wk caloric restriction with and without aerobic exercise (CR + EX, n = 48; and CR, n = 22). Blood samples were collected for measuring plasma adiponectin concentration, and abdominal and gluteal subcutaneous adipose tissue biopsies were performed in a subgroup to determine in vitro adiponectin release, before and after the interventions.

RESULTS

The interventions elicited similar amounts of weight loss (CR + EX, -11.3 ± 4.6 kg; CR,-11.2 ± 3.4 kg) and fat loss (CR + EX, -8.0 ± 3.5 kg; CR, -7.4 ± 2.7 kg). The two groups had differential changes in plasma adiponectin concentrations (for interaction, P = 0.014); CR + EX increased (6.9 ± 3.9 to 8.5 ± 4.9 μg·mL(-1); P = 0.0001), whereas CR did not alter (6.4 ± 4.4 to 6.5 ± 4.5 μg·mL(-1); P = 0.42) plasma adiponectin. Likewise, adiponectin release from abdominal and gluteal subcutaneous adipose tissue increased with CR + EX (P = 0.0076 and P = 0.089, respectively) but did not change with CR (P = 0.13 and P = 0.95, respectively).

CONCLUSION

Despite similar reductions in body weight and fat mass, the addition of aerobic exercise to caloric restriction increased plasma adiponectin concentrations, which may be partly explained by increased adiponectin release from abdominal and gluteal subcutaneous adipose tissue.

The Anti-Inflammatory Actions of Exercise Training

The list of diseases with a known inflammatory etiology is growing. Cardiovascular disease, osteoporosis, diabetes, geriatric cachexia, and Alzheimer's disease have all been shown to be linked to or exacerbated by aberrantly regulated inflammatory processes. Nevertheless, there is mounting evidence that those who are physically active, or who become physically active, have a reduction in biomarkers associated with chronic inflammation. There was strong early consensus that exercise-induced reductions in inflammation were explained by body mass index or body fatness, but recent studies provide support for the contention that exercise has body fat-independent anti-inflammatory effects. With few exceptions, the anti-inflammatory effects of exercise appear to occur regardless of age or the presence of chronic diseases. What remains unclear are the mechanisms by which exercise training induces these anti-inflammatory effects, but there are several intriguing possibilities, including release of endogenous products, such as heat shock proteins; selective reduction of visceral adipose tissue mass or reducing infiltration of adipocytes by macrophages; shift in immune cell phenotype; cross-tolerizing effects; or exercise-induced shifts in accessory proteins of toll-like receptor signaling. However, future research endeavors are likely to uncover additional potential mechanisms, and it could be some time before functional mechanisms are made clear. In summary, the potential anti-inflammatory influences of exercise training may provide a low-cost, readily available, and effective treatment for low-grade systemic inflammation and could contribute significantly to the positive effects of exercise training on chronic disease.

Effects of Exercise Training on Cardiorespiratory Fitness and Biomarkers of Cardiometabolic Health: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Guidelines recommend exercise for cardiovascular health, although evidence from trials linking exercise to cardiovascular health through intermediate biomarkers remains inconsistent. We performed a meta-analysis of randomized controlled trials to quantify the impact of exercise on cardiorespiratory fitness and a variety of conventional and novel cardiometabolic biomarkers in adults without cardiovascular disease.

METHODS AND RESULTS

Two researchers selected 160 randomized controlled trials (7487 participants) based on literature searches of Medline, Embase, and Cochrane Central (January 1965 to March 2014). Data were extracted using a standardized protocol. A random-effects meta-analysis and systematic review was conducted to evaluate the effects of exercise interventions on cardiorespiratory fitness and circulating biomarkers. Exercise significantly raised absolute and relative cardiorespiratory fitness. Lipid profiles were improved in exercise groups, with lower levels of triglycerides and higher levels of high-density lipoprotein cholesterol and apolipoprotein A1. Lower levels of fasting insulin, homeostatic model assessment-insulin resistance, and glycosylated hemoglobin A1c were found in exercise groups. Compared with controls, exercise groups had higher levels of interleukin-18 and lower levels of leptin, fibrinogen, and angiotensin II. In addition, we found that the exercise effects were modified by age, sex, and health status such that people aged <50 years, men, and people with type 2 diabetes, hypertension, dyslipidemia, or metabolic syndrome appeared to benefit more.

CONCLUSIONS

This meta-analysis showed that exercise significantly improved cardiorespiratory fitness and some cardiometabolic biomarkers. The effects of exercise were modified by age, sex, and health status. Findings from this study have significant implications for future design of targeted lifestyle interventions.

The contribution of childhood cardiorespiratory fitness and adiposity to inflammation in young adults

OBJECTIVE

Cardiorespiratory fitness and adiposity may influence cardiovascular risk through their effects on inflammation. The long-term effects of these modifiable factors on adult inflammation remain uncertain. The associations of childhood and adulthood cardiorespiratory fitness and adiposity with adult inflammation [C-reactive protein (CRP), fibrinogen] were examined.

METHODS

1,976 children examined in 1985 and re-examined as young adults in 2004-2006 were included. Cardiorespiratory fitness and adiposity were assessed at both waves. CRP and fibrinogen were measured at follow-up.

RESULTS

Higher childhood fitness was associated with lower adult inflammation in both sexes. After adjusting for childhood adiposity, the association with CRP attenuated in males, but remained in females (average reduction of CRP 18.1% (95% CI 11.3-24.4%) per 1-SD increase in childhood fitness). Higher adult fitness, adjusting for childhood fitness (an increase in fitness from childhood to adulthood), was associated with lower adult CRP in females and lower fibrinogen in males. Higher childhood and adulthood adiposity (an increase in adiposity from childhood to adulthood) were associated with higher adult inflammation in both sexes.

CONCLUSIONS

Prevention programs to increase fitness and reduce adiposity in childhood, and maintain a favorable fitness and weight into adulthood, may lead to reduction in adult systemic inflammation.

Lifestyle-induced decrease in fat mass improves adiponectin secretion in obese adults

PURPOSE

Several studies have identified relationships between weight loss and adipokine levels; however, none have looked at the combined effect of aerobic exercise training with the consumption of a low- or a high-glycemic diet. We examined the effects of 12 wk of aerobic exercise combined with either a low-glycemic index diet (∼40 U) plus exercise (LoGIX) or a high-glycemic index diet (∼80 U) diet plus exercise (HiGIX) on plasma leptin and adiponectin (total and high molecular weight [HMW]) in 27 older obese adults (age = 65 ± 0.5 yr, body mass index = 34.5 ± 0.7 kg·m).

METHODS

Insulin sensitivity was calculated from an oral glucose tolerance test. Fasting HMW adiponectin and leptin were quantified from plasma samples obtained before the insulin sensitivity index obtained from the oral glucose tolerance test. Glucose and insulin measures were obtained before and every 30 min during the test. Dual-energy x-ray absorptiometry and computerized tomography were used to determine body composition and to quantify subcutaneous and visceral abdominal adiposity, respectively.

RESULTS

Fasting leptin was significantly decreased in both groups (LoGIX: preintervention = 33.8 ± 4.7, postintervention = 19.2 ± 4.5; HiGIX: preintervention = 27.9 ± 4.2, postintervention = 11.9 ± 2.2 ng·mL; P = 0.004), and HMW adiponectin was significantly increased (LoGIX: preintervention = 1606.9 ± 34.6, postintervention = 3502.3 ± 57; HiGIX: preintervention = 3704.8 ± 38.1, postintervention = 4284.3 ± 52.8 pg·mL; P = 0.003) after the 12-wk intervention. Total body fat was reduced after both interventions. Visceral fat mass was inversely correlated with HMW adiponectin, whereas subcutaneous fat correlated with leptin.

CONCLUSIONS

The data suggest that exercise training, independent of dietary glycemic index, favorably alters HMW adiponectin and leptin secretion and that a reduction in visceral fat mass is a key factor regulating HMW adiponectin in older obese persons.

Regional adipose tissue hormone/cytokine production before and after weight loss in abdominally obese women

OBJECTIVE

To compare the regional differences in subcutaneous adipose tissue hormone/cytokine production in abdominally obese women during weight loss.

METHODS

Forty-two abdominally obese, older women underwent a 20-week weight loss intervention composed of hypocaloric diet with or without aerobic exercise (total energy expenditure: ∼2800 kcal/week). Subcutaneous (gluteal and abdominal) adipose tissue biopsies were conducted before and after the intervention. Adipose tissue gene expression and release of leptin, adiponectin, and interleukin 6 (IL-6) were determined.

RESULTS

The intervention resulted in significant weight loss (-10.1 ± 0.7 kg, P < 0.001). At baseline, gene expression of adiponectin were higher (P < 0.01), and gene expression and release of IL-6 were lower (both P < 0.05) in abdominal than in gluteal adipose tissue. After intervention, leptin gene expression and release were lower in both gluteal and abdominal adipose tissue compared to baseline (P < 0.05-0.01). Abdominal, but not gluteal, adipose tissue adiponectin gene expression and release increased after intervention (both P < 0.05).

CONCLUSION

A 20-week weight loss program decreased leptin production in both gluteal and abdominal adipose tissue, but only increased adiponectin production from abdominal adipose tissue in obese women. This depot-specific effect may be of importance for the treatment of health complications associated with abdominal adiposity.

Obesity, adiposity, and dyslipidemia: a consensus statement from the National Lipid Association

The term "fat" may refer to lipids as well as the cells and tissue that store lipid (ie, adipocytes and adipose tissue). "Lipid" is derived from "lipos," which refers to animal fat or vegetable oil. Adiposity refers to body fat and is derived from "adipo," referring to fat. Adipocytes and adipose tissue store the greatest amount of body lipids, including triglycerides and free cholesterol. Adipocytes and adipose tissue are active from an endocrine and immune standpoint. Adipocyte hypertrophy and excessive adipose tissue accumulation can promote pathogenic adipocyte and adipose tissue effects (adiposopathy), resulting in abnormal levels of circulating lipids, with dyslipidemia being a major atherosclerotic coronary heart disease risk factor. It is therefore incumbent upon lipidologists to be among the most knowledgeable in the understanding of the relationship between excessive body fat and dyslipidemia. On September 16, 2012, the National Lipid Association held a Consensus Conference with the goal of better defining the effect of adiposity on lipoproteins, how the pathos of excessive body fat (adiposopathy) contributes to dyslipidemia, and how therapies such as appropriate nutrition, increased physical activity, weight-management drugs, and bariatric surgery might be expected to impact dyslipidemia. It is hoped that the information derived from these proceedings will promote a greater appreciation among clinicians of the impact of excess adiposity and its treatment on dyslipidemia and prompt more research on the effects of interventions for improving dyslipidemia and reducing cardiovascular disease risk in overweight and obese patients.

Resveratrol Is Not as Effective as Physical Exercise for Improving Reproductive and Metabolic Functions in Rats with Dihydrotestosterone-Induced Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a reproductive and metabolic disorder associated with obesity and insulin resistance that often precedes the development of type-2 diabetes. Rats continuously exposed to dihydrotestosterone from prepuberty display typical reproductive and metabolic PCOS characteristics including anovulation, polycystic ovaries, insulin resistance, and obesity. Our aim was to investigate if resveratrol improves reproductive and metabolic functions in PCOS rats. The effect was compared to exercise. Control and PCOS rats were treated with vehicle or resveratrol (400 mg · kg−1 · day−1) for 5-6 weeks. Another group of PCOS rats received vehicle treatment and exercised for 5-6 weeks. Insulin sensitivity was determined by euglycemic-hyperinsulinemic clamp. The glucose infusion rate was lower in the PCOS-vehicle group compared to control-vehicle rats (P<0.05). Exercise increased insulin sensitivity compared with PCOS-vehicle rats (P<0.05), but resveratrol did not. Resveratrol treatment and exercise resulted in smaller adipocytes, upregulated estrogen-related receptorαgene expression in subcutaneous fat, and improved estrus cyclicity in the previously acyclic PCOS rats. Although resveratrol had positive effects on adiposity and cyclicity in a similar manner to exercise, resveratrol does not seem to be a good candidate for treating insulin resistance associated with PCOS because no improvement in insulin sensitivity was observed in PCOS rats on normal chow.

Adaptation of human adipose tissue to hypocaloric diet

Hypocaloric diet is a key component of the weight-reducing treatment of obesity and obesity-related disorders. Hypocaloric diets and the associated weight reduction promote improvement of metabolic profile of obese individuals. Among the mechanisms that underlie this beneficial metabolic outcome, the diet-induced modifications of morphological and functional characteristics of human adipose tissue (AT) are believed to have an important role. Prospective studies of hypocaloric weight-reducing dietary intervention demonstrate effects on adipocyte metabolism, namely lipolysis and lipogenesis, and associated changes of the adipocyte size. The endocrine function of AT, which involves cytokine and adipokine production by adipocytes, as well as by cells of stromavascular fraction, is also regulated by dietary intervention. Related inflammatory status of AT is modulated also as a consequence of the changes in recruitment of immune cells, mainly macrophages, in AT. Here, we give an overview of metabolic and endocrine modifications in human AT induced by a variety of hypocaloric diets.

Physical activity and exercise in the regulation of human adipose tissue physiology

Physical activity and exercise are key components of energy expenditure and therefore of energy balance. Changes in energy balance alter fat mass. It is therefore reasonable to ask: What are the links between physical activity and adipose tissue function? There are many complexities. Physical activity is a multifaceted behavior of which exercise is just one component. Physical activity influences adipose tissue both acutely and in the longer term. A single bout of exercise stimulates adipose tissue blood flow and fat mobilization, resulting in delivery of fatty acids to skeletal muscles at a rate well-matched to metabolic requirements, except perhaps in vigorous intensity exercise. The stimuli include adrenergic and other circulating factors. There is a period following an exercise bout when fatty acids are directed away from adipose tissue to other tissues such as skeletal muscle, reducing dietary fat storage in adipose. With chronic exercise (training), there are changes in adipose tissue physiology, particularly an enhanced fat mobilization during acute exercise. It is difficult, however, to distinguish chronic "structural" changes from those associated with the last exercise bout. In addition, it is difficult to distinguish between the effects of training per se and negative energy balance. Epidemiological observations support the idea that physically active people have relatively low fat mass, and intervention studies tend to show that exercise training reduces fat mass. A much-discussed effect of exercise versus calorie restriction in preferentially reducing visceral fat is not borne out by meta-analyses. We conclude that, in addition to the regulation of fat mass, physical activity may contribute to metabolic health through beneficial dynamic changes within adipose tissue in response to each activity bout.

Adipose tissue endocannabinoid system gene expression: depot differences and effects of diet and exercise

BACKGROUND

Alterations of endocannabinoid system in adipose tissue play an important role in lipid regulation and metabolic dysfunction associated with obesity. The purpose of this study was to determine whether gene expression levels of cannabinoid type 1 receptor (CB1) and fatty acid amide hydrolase (FAAH) are different in subcutaneous abdominal and gluteal adipose tissue, and whether hypocaloric diet and aerobic exercise influence subcutaneous adipose tissue CB1 and FAAH gene expression in obese women.

METHODS

Thirty overweight or obese, middle-aged women (BMI = 34.3 ± 0.8 kg/m2, age = 59 ± 1 years) underwent one of three 20-week weight loss interventions: caloric restriction only (CR, N = 9), caloric restriction plus moderate-intensity aerobic exercise (CRM, 45-50% HRR, N = 13), or caloric restriction plus vigorous-intensity aerobic exercise (CRV, 70-75% HRR, N = 8). Subcutaneous abdominal and gluteal adipose tissue samples were collected before and after the interventions to measure CB1 and FAAH gene expression.

RESULTS

At baseline, FAAH gene expression was higher in abdominal, compared to gluteal adipose tissue (2.08 ± 0.11 vs. 1.78 ± 0.10, expressed as target gene/β-actin mRNA ratio × 10-3, P < 0.05). Compared to pre-intervention, CR did not change abdominal, but decreased gluteal CB1 (Δ = -0.82 ± 0.25, P < 0.05) and FAAH (Δ = -0.49 ± 0.14, P < 0.05) gene expression. CRM or CRV alone did not change adipose tissue CB1 and FAAH gene expression. However, combined CRM and CRV (CRM+CRV) decreased abdominal adipose tissue FAAH gene expression (Δ = -0.37 ± 0.18, P < 0.05). The changes in gluteal CB1 and abdominal FAAH gene expression levels in the CR alone and the CRM+CRV group were different (P < 0.05) or tended to be different (P = 0.10).

CONCLUSIONS

There are depot differences in subcutaneous adipose tissue endocannabinoid system gene expression in obese individuals. Aerobic exercise training may preferentially modulate abdominal adipose tissue endocannabinoid-related gene expression during dietary weight loss.

Pericardial fat loss in postmenopausal women under conditions of equal energy deficit

Weight loss induced by caloric restriction (CR) or aerobic exercise can reduce pericardial fat, and these reductions may help improve cardiovascular health.

PURPOSE

We examined whether combining CR with aerobic exercise enhances pericardial fat loss compared with a CR-only intervention designed to elicit equivalent reductions in body weight. We also examined the relationship between changes in pericardial fat and changes in maximal oxygen consumption (V˙O2max), a measure of cardiorespiratory fitness.

METHODS

Thirty-two abdominally obese postmenopausal women (mean age=58 yr; 78% Caucasian) were randomly assigned to one of three interventions of equal energy deficit (∼2800 kcal·wk) for 20 wk: CR only (n=8), CR + moderate-intensity exercise (n=15), or CR + vigorous-intensity exercise (n=9). The volume of pericardial fat around the coronary arteries was measured by computed tomography.

RESULTS

Women in the CR, CR + moderate-intensity, and CR + vigorous-intensity groups had similar baseline characteristics. The mean ± SD value for pericardial fat before weight loss was 79.07 ± 32.90 cm (range=34.04-152.74 cm), with no difference among groups (P=0.89). All three interventions significantly reduced body weight (15%), waist circumference (10%), and abdominal visceral fat (28%) to a similar degree. There was also a 17% reduction in pericardial fat (-12.75 ± 6.29 cm, P<0.0001), which did not differ among groups (P=0.84). Changes in pericardial fat were inversely correlated with changes in V˙O2max (r=-0.37, P=0.05), but not after adjusting for intervention group and change in body weight.

CONCLUSIONS

Weight loss interventions of equal energy deficit have similar effects on pericardial fat in postmenopausal women, regardless of whether the energy deficit is due to CR alone or CR plus aerobic exercise.

Strategies for reducing body fat mass: effects of liposuction and exercise on cardiovascular risk factors and adiposity

Liposuction is the most popular aesthetic surgery performed in Brazil and worldwide. Evidence showing that adipose tissue is a metabolically active tissue has led to the suggestion that liposuction could be a viable method for improving metabolic profile through the immediate loss of adipose tissue. However, the immediate liposuction-induced increase in the proportion of visceral to subcutaneous adipose tissue could be detrimental to metabolism, because a high proportion of visceral to subcutaneous adipose tissue is associated with risk factors for cardiovascular disease. The results of studies investigating the effects of liposuction on the metabolic profile are inconsistent, however, with most studies reporting either no change or improvements in one or more cardiovascular risk factors. In addition, animal studies have demonstrated a compensatory growth of intact adipose tissue in response to lipectomy, although studies with humans have reported inconsistent results. Exercise training improves insulin sensitivity, inflammatory balance, lipid oxidation, and adipose tissue distribution; increases or preserves the fat-free mass; and increases total energy expenditure. Thus, liposuction and exercise appear to directly affect metabolism in similar ways, which suggests a possible interaction between these two strategies. To our knowledge, no studies have reported the associated effects of liposuction and exercise in humans. Nonetheless, one could suggest that exercise training associated with liposuction could attenuate or even block the possible compensatory fat deposition in intact depots or regrowth of the fat mass and exert an additive or even a synergistic effect to liposuction on improving insulin sensitivity and the inflammatory balance, resulting in an improvement of cardiovascular risk factors. Consequently, one could suggest that liposuction and exercise appear to be safe and effective strategies for either the treatment of metabolic disorders or aesthetic purposes.

Improving physical activity and dietary behaviours with single or multiple health behaviour interventions? A synthesis of meta-analyses and reviews

Since multiple health behaviour interventions have gained popularity, it is important to investigate their effectiveness compared to single health behaviour interventions. This synthesis aims to determine whether single intervention (physical activity or dietary) or multiple interventions (physical activity and dietary) are more effective at increasing these behaviours by synthesizing reviews and meta-analyses. A sub-purpose also explored their impact on weight. Overall, reviews/meta-analyses showed that single health behaviour interventions were more effective at increasing the targeted behaviours, while multiple health behaviour interventions resulted in greater weight loss. This review may assist policies aiming at improving physical activity and nutrition and reversing the obesity epidemic.

Reduction in trunk fat predicts cardiovascular exercise training-related reductions in C-reactive protein

C-reactive protein (CRP) is an independent risk factor for cardiovascular disease. We sought to determine (1) if 10 months of cardiovascular exercise training (Cardio) reduces CRP in a group of older adults, (2) if such a reduction is related to improvements in trunk fat, fitness, and/or psychosocial variables, and (3) if the effect of Cardio on CRP differs between men and women. Community-dwelling residents (n=127; 60-83 yrs) were randomized to a Flex group (n=61) where they participated in 2-75 min supervised sessions per wk during which they performed non-cardiovascular flexibility and balance exercises or a Cardio group (n=66) where they participated in three supervised sessions per wk during which they performed cardiovascular exercises for approximately 45-60 min at 60-70% maximal oxygen uptake. The main outcome measures were serum CRP, cardiovascular fitness, total and central adiposity, and self-reported psychosocial function. Cardio experienced a reduction in CRP (-0.5mg/L), as well as improvements in fitness (+7%) and total (-1.5%) and central (i.e., trunk) (-2.5%) adiposity. These relationships were not modified by sex. Regression analyses indicated that only the reduction in trunk fat was significantly related to the reduction in CRP. Ten months of cardiovascular exercise training reduced CRP in previously sedentary older adults and this effect was partially mediated by a reduction in trunk fat.

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.

Low-frequency electro-acupuncture and physical exercise improve metabolic disturbances and modulate gene expression in adipose tissue in rats with dihydrotestosterone-induced polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder associated with ovulatory dysfunction, hyperandrogenism, abdominal obesity, and insulin resistance. Pharmacotherapy is often unsatisfactory. This study evaluates the effects of low-frequency electro-acupuncture (EA) and physical exercise on metabolic disturbances and adipose tissue mRNA expression of selected genes in a rat PCOS model characterized by insulin resistance and adiposity. Dihydrotestosterone (inducing PCOS) or vehicle (control) was administrated continuously, beginning before puberty. At age 10 wk, PCOS rats were randomly divided into three groups; PCOS, PCOS EA, and PCOS exercise. PCOS EA rats received 2-Hz EA (evoking muscle twitches) three times/wk during 4-5 wk. PCOS exercise rats had free access to a running wheel for 4-5 wk. EA and exercise improved insulin sensitivity, measured by clamp, in PCOS rats. Exercise also reduced adiposity, visceral adipocyte size, and plasma leptin. EA increased plasma IGF-I. Real-time RT-PCR revealed increased expression of leptin and IL-6 and decreased expression of uncoupling protein 2 in visceral adipose tissue of PCOS rats compared with controls. EA restored the expression of leptin and uncoupling protein 2, whereas exercise normalized adipose tissue leptin and IL-6 expression in PCOS rats. Thus, EA and exercise ameliorate insulin resistance in rats with PCOS. This effect may involve regulation of adipose tissue metabolism and production because EA and exercise each partly restore divergent adipose tissue gene expression associated with insulin resistance, obesity, and inflammation. In contrast to exercise, EA improves insulin sensitivity and modulates adipose tissue gene expression without influencing adipose tissue mass and cellularity.

Lean mass loss is associated with low protein intake during dietary-induced weight loss in postmenopausal women

The health and quality-of-life implications of overweight and obesity span all ages in the United States. We investigated the association between dietary protein intake and loss of lean mass during weight loss in postmenopausal women through a retrospective analysis of a 20-week randomized, controlled diet and exercise intervention in women aged 50 to 70 years. Weight loss was achieved by differing levels of caloric restriction and exercise. The diet-only group reduced caloric intake by 2,800 kcal/week, and the exercise groups reduced caloric intake by 2,400 kcal/week and expended approximately 400 kcal/week through aerobic exercise. Total and appendicular lean mass was measured using dual energy x-ray absorptiometry. Linear regression analysis was used to examine the association between changes in lean mass and appendicular lean mass and dietary protein intake. Average weight loss was 10.8+/-4.0 kg, with an average of 32% of total weight lost as lean mass. Protein intake averaged 0.62 g/kg body weight/day (range=0.47 to 0.8 g/kg body weight/day). Participants who consumed higher amounts of dietary protein lost less lean mass and appendicular lean mass (r=0.3, P=0.01 and r=0.41, P<0.001, respectively). These associations remained significant after adjusting for intervention group and body size. Therefore, inadequate protein intake during caloric restriction may be associated with adverse body-composition changes in postmenopausal women.

Subcutaneous fat alterations resulting from an upper-body resistance training program

PURPOSE

It is believed spot reduction, the exercise-induced localized loss of subcutaneous fat, does not occur as a result of an exercise program; however, evidence as a whole has been inconsistent. To reexamine this concept, we compared subcutaneous fat measurements before and after resistance training among 104 subjects (45 men, 59 women).

METHODS

Subjects participated in 12 wk of supervised resistance training of their nondominant arm. Magnetic resonance imaging and skinfold calipers examined subcutaneous fat in the nondominant (trained) and dominant (untrained) arms before and after resistance training. Repeated-measures ANCOVA tested for subcutaneous fat differences within and between arms before, after, and from before to after resistance training by gender and measurement technique, with BMI and age as covariates. Simple linear regression compared subcutaneous fat changes before and after resistance training as assessed by MRI and skinfold.

RESULTS

Subcutaneous fat, measured by skinfold, decreased in the trained arm and not the untrained arm in the men (P < 0.01); it was similar in the total sample and in the women (P > 0.05). MRI determinations of subcutaneous fat changes were not different between arms in the total sample and by gender (P > 0.05).

CONCLUSION

Subcutaneous fat changes resulting from resistance training varied by gender and assessment technique. Skinfold findings indicate that spot reduction occurred in men but not in women. In contrast, MRI found a generalized subcutaneous fat loss independent of gender, supporting the notion that spot reduction does not occur as a result of resistance training. MRI, sensitive to changes along the entire upper arm, detected greater variation in resistance training responses, preventing significant differences between trained and untrained arms. Variation in upper-arm resistance training response was not evident from a single skinfold measurement at the belly of the muscle.

Aortic stiffness and pulse pressure amplification in Wistar-Kyoto and spontaneously hypertensive rats

In humans, increased body weight and arterial stiffness are significantly associated, independently of blood pressure (BP) level. The finding was never investigated in rodents devoid of metabolic disorders as spontaneously hypertensive rats (SHR). Using simultaneous catheterization of proximal and distal aorta, we measured body weight, intra-arterial BP, heart rate and their variability (spectral analysis), aortic pulse wave velocity (PWV), and systolic and pulse pressure (PP) amplifications in unrestrained conscious Wistar-Kyoto (WKY) rats and SHR between 6 and 24 wk of age. Aortic proximal systolic and diastolic pressure, PP, and mean BP were significantly higher in SHR than in WKY rats and increased significantly with age (with the exception of PP). PP amplification increased with age but did not differ between strains. PWV was significantly associated with heart rate variability. PWV was significantly higher (via two-way variance analysis) in SHR than in WKY rats (strain effect) and increased markedly with age in both strains (age effect). Adjustment of PWV to mean BP attenuated markedly both the age and the strain effects. After adjustment for body weight, either alone or associated with mean BP, the age effect was not more significant, but the strain effect was markedly enhanced. In conscious unanesthetized SHR and WKY rats, aortic stiffness is consistently associated with body weight independent of age and mean BP. An intervention study should consider in the objectives systolic BP and PP amplifications measured in conscious animals, central control of body weight, and autonomic nervous system.

The relative influences of fitness and fatness on inflammatory factors

OBJECTIVE

Inflammatory processes contribute to disease pathways and may be affected by behavioral lifestyle factors. The relative contributions of fatness and cardiorespiratory fitness to inflammatory factors remain unclear. The present review examines the hypothesis that the association between fitness and inflammatory factors is independent of fatness.

METHODS

Data were examined from 40 observational studies on the association between fitness/physical activity and inflammatory factors after making statistical adjustment for measures of fatness, and from 12 randomized controlled trials that considered the impact of improved fitness and weight loss.

RESULTS

Two thirds of the observational studies report an inverse relationship between inflammatory factors and fitness after adjustment for fatness. Evidence from randomized controlled trials does not consistently support the hypothesis. Inconsistencies in the literature may be related to various factors such as age, gender, and disease status.

CONCLUSIONS

Both fitness and fatness appear to contribute to inflammatory factors, although it is unclear whether fatness is a mediator or if both fitness and fatness share the same causal pathways. Lifestyle interventions for primary prevention in the general public should therefore focus on both increasing physical activity and the prevention of excess adiposity, although the optimal exercise dose and body composition for preventing chronic inflammatory processes is not well established.