***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Overweight and obesity affects more than 66 % of the adult population and is associated with a variety of chronic diseases . Weight reduction reduces health risks associated with chronic diseases and is therefore encouraged by major health agencies . Guidelines of the National Heart , Lung , and Blood Institute ( NHLBI ) encourage a 10 % reduction in weight , although considerable literature indicates reduction in health risk with 3 % to 5 % reduction in weight . Physical activity ( PA ) is recommended as a component of weight management for prevention of weight gain , for weight loss , and for prevention of weight regain after weight loss . In 2001 , the American College of Sports Medicine ( ACSM ) published a Position St and that recommended a minimum of 150 min wk(-1 ) of moderate-intensity PA for overweight and obese adults to improve health ; however , 200 - 300 min wk(-1 ) was recommended for long-term weight loss . More recent evidence has supported this recommendation and has indicated more PA may be necessary to prevent weight regain after weight loss . To this end , we have reexamined the evidence from 1999 to determine whether there is a level at which PA is effective for prevention of weight gain , for weight loss , and prevention of weight regain . Evidence supports moderate-intensity PA between 150 and 250 min wk(-1 ) to be effective to prevent weight gain .  Moderate-intensity PA between 150 and 250 min wk(-1 ) will provide only modest weight loss . Greater amounts of PA ( > 250 min wk(-1 ) ) have been associated with clinical ly significant weight loss .  Moderate-intensity PA between 150 and 250 min wk(-1 ) will improve weight loss in studies that use moderate diet restriction but not severe diet restriction . Cross-sectional and prospect i ve studies indicate that after weight loss , weight maintenance is improved with PA > 250 min wk(-1 ) . However , no evidence from well- design ed r and omized controlled trials exists to judge the effectiveness of PA for prevention of weight regain after weight loss .  Resistance training does not enhance weight loss but may increase fat-free mass and increase loss of fat mass and is associated with reductions in health risk . Existing evidence indicates that endurance PA or resistance training without weight loss improves health risk . There is inadequate evidence to determine whether PA prevents or attenuates detrimental changes in chronic disease risk during weight gain The purpose of this study was to determine the effects of exercise training on ventricular epicardial fat  thickness in obese men and to investigate the relationship of the change in epicardial fat thickness to changes in abdominal fat tissue following exercise training .  Twenty-four obese middle-aged men [ age , 49.4 + /- 9.6 yr ; weight , 87.7 + /- 11.2 kg ; body mass index ( BMI ) , 30.7 + /- 3.3 kg/m(2 ) ; peak oxygen consumption , 28.4 + /- 7.2 ml.kg(-1).min(-1 ) ; means + /- SD ] participated in this study . Each participant completed a 12-wk supervised exercise training program ( 60 - 70 % of the maximal heart rate ; 60 min/day , 3 days/wk ) and underwent a transthoracic echocardiography . The epicardial fat thickness on the free wall of the right ventricle was measured from both parasternal long- and short-axis views . The visceral adipose tissue ( VAT ) and subcutaneous adipose tissues were measured by computed tomography . Following exercise training , the epicardial fat thickness was significantly decreased ( P < 0.001 ) . The percentage change of epicardial fat thickness was twice as high compared with those of waist , BMI , and body weight of original values ( P < 0.05 ) . There was a significant relationship ( r = 0.525 , P = 0.008 ) between changes in the epicardial fat thickness and VAT with exercise training . Stepwise multiple regression analysis revealed that the change in VAT , change in systolic blood pressure , and change in quantitative insulin sensitivity check index were independently related to the change epicardial fat thickness ( P < 0.05 ) . The ventricular epicardial fat thickness is reduced significantly after aerobic exercise training and is associated with a decrease in VAT . These results suggest that aerobic exercise training may be an effective nonpharmacological strategy for decreasing the ventricular epicardial fat thickness and visceral fat area in obese middle-aged men BACKGROUND & AIMS We determined the effects of acute and chronic calorie restriction with either a low-fat , high-carbohydrate ( HC ) diet or a low-carbohydrate ( LC ) diet on hepatic and skeletal muscle insulin sensitivity . METHODS Twenty-two obese subjects ( body mass index , 36.5 + /- 0.8 kg/m2 ) were r and omized to an HC ( > 180 g/day ) or LC ( < 50 g/day ) energy-deficit diet . A euglycemic-hyperinsulinemic clamp , muscle biopsy specimens , and magnetic resonance spectroscopy were used to determine insulin action , cellular insulin signaling , and intrahepatic triglyceride ( IHTG ) content before , after 48 hours , and after approximately 11 weeks ( 7 % weight loss ) of diet therapy . RESULTS At 48 hours , IHTG content decreased more in the LC than the HC diet group ( 29.6 % + /- 4.8 % vs 8.9 % + /- 1.4 % ; P < .05 ) but was similar in both groups after 7 % weight loss ( LC diet , 38.0 % + /- 4.5 % ; HC diet , 44.5 % + /- 13.5 % ) . Basal glucose production rate decreased more in the LC than the HC diet group at 48 hours ( 23.4 % + /- 2.2 % vs 7.2 % + /- 1.4 % ; P < .05 ) and after 7 % weight loss ( 20.0 % + /- 2.4 % vs 7.9 % + /- 1.2 % ; P < .05 ) . Insulin-mediated glucose uptake did not change at 48 hours but increased similarly in both groups after 7 % weight loss ( 48.4 % + /- 14.3 % ; P < .05 ) . In both groups , insulin-stimulated phosphorylation of c-Jun-N-terminal kinase decreased by 29 % + /- 13 % and phosphorylation of Akt and insulin receptor substrate 1 increased by 35 % + /- 9 % and 36 % + /- 9 % , respectively , after 7 % weight loss ( all P < .05 ) . CONCLUSIONS Moderate calorie restriction causes temporal changes in liver and skeletal muscle metabolism ; 48 hours of calorie restriction affects the liver ( IHTG content , hepatic insulin sensitivity , and glucose production ) , whereas moderate weight loss affects muscle ( insulin-mediated glucose uptake and insulin signaling ) OBJECTIVE Nonalcoholic fatty liver disease ( NAFLD ) and its association with insulin resistance are increasingly recognized as major health burdens . The main objectives of this study were to assess the relation between liver lipid content and serum lipids , markers of liver function and inflammation in healthy overweight subjects , and to determine whether caloric restriction ( CR ) ( which improves insulin resistance ) reduces liver lipids in association with these same measures . METHODS AND PROCEDURES Forty-six white and black overweight men and women ( BMI = 24.7 - 31.3 kg/m(2 ) ) were r and omized to " control ( CO ) " = 100 % energy requirements ; " CR " = 25 % ; " caloric restriction and increased structured exercise (CR+EX)"= 12.5 % CR + 12.5 % increase in energy expenditure through exercise ; or " low-calorie diet ( LCD ) " = 15 % weight loss by liquid diet followed by weight-maintenance , for 6 months . Liver lipid content was assessed by magnetic resonance spectroscopy ( MRS ) and computed tomography ( CT ) . Lipid concentrations , markers of liver function ( alanine aminotransferase ( ALT ) , alkaline phosphatase ( ALK ) ) , and whole-body inflammation ( tumor necrosis factor-alpha ( TNF-alpha ) , interleukin-6 ( IL-6 ) , high-sensitivity C-reactive protein ( hsCRP ) ) were measured in fasting blood . RESULTS At baseline , increased liver lipid content ( by MRS ) correlated ( P < 0.05 ) with elevated fasting triglyceride ( r = 0.52 ) , ALT ( r = 0.42 ) , and hsCRP ( r = 0.33 ) concentrations after adjusting for sex , race , and alcohol consumption . With CR , liver lipid content was significantly lowered by CR , CR+EX , and LCD ( detected by MRS only ) . The reduction in liver lipid content , however , was not significantly correlated with the reduction in triglycerides ( r = 0.26 ; P = 0.11 ) or with the changes in ALT , high-density lipoprotein (HDL)-cholesterol , or markers of whole-body inflammation . DISCUSSION CR may be beneficial for reducing liver lipid and lowering triglycerides in overweight subjects without known NAFLD We evaluated the influence of measurement site on the ranking ( low to high ) of  abdominal subcutaneous ( SAT ) and visceral ( VAT ) adipose tissue .  We also determined the influence of measurement site on the prediction of abdominal SAT and VAT mass . The subjects included 100 men with computed tomography ( CT ) measurements at L4-L5 and L3-L4 levels and 100 men with magnetic resonance imaging ( MRI ) measurements at L4-L5 and 5 cm above L4-L5 ( L4-L5 + 5 cm ) . Corresponding mass values were determined by using multiple-image protocol s. For SAT , 90 and 92 of the 100 subjects for CT and MRI , respectively , had a difference in rank position at the two levels . The change in rank position exceeded the error or measurement for approximately 75 % of the subjects for both methods . For VAT , 91 and 95 of the 100 subjects for CT and MRI , respectively , had a difference in rank position at the two levels . The change in rank position exceeded the error of measurement for 36 % of the subjects for CT and for 8 % of the subjects for MRI . For both imaging modalities , the variance explained in SAT and VAT mass ( kg ) was comparable for L4-L5 , L4-L5 + 5 cm , and L3-L4 levels . In conclusion , the ranking of subjects for abdominal SAT and VAT quantity is influenced by measurement location . However , the ability to predict SAT and VAT mass by using single images obtained at the L4-L5 , L4-L5 + 5 cm , or L3-L4 levels is comparable Objective —To examine the association between liver fat content and very low-density lipoprotein (VLDL)–apolipoprotein ( apo ) B-100 kinetics and the corresponding responses to weight loss  in obese subjects . Methods and Results —VLDL – apoB-100 kinetics were assessed using stable isotope tracers , and the fat content of the liver and abdomen was determined by magnetic resonance techniques in 25 obese subjects . In univariate analysis , liver fat content was significantly ( P<0.05 in all ) associated with body mass index ( r=0.65 ) , visceral fat area ( r=0.45 ) , triglycerides ( r=0.40 ) , homeostasis model assessment score ( r=0.40 ) , VLDL – apoB-100 concentrations ( r=0.44 ) , and secretion rate ( r=0.45 ) . However , liver fat content was not associated with plasma concentrations of retinol-binding protein 4 , fetuin A , adiponectin , interleukin-6 , and tumor necrosis factor-&agr;. Of these 25 subjects , 9 diagnosed as having nonalcoholic fatty liver disease ( which is highly prevalent in obese individuals and strongly associated with dyslipidemia ) underwent a weight loss program . The low-fat diet achieved significant reduction in body weight , body mass index , liver fat , visceral and subcutaneous fat areas , homeostasis model assessment score , triglycerides , VLDL – apoB-100 concentrations , and VLDL – apoB-100 secretion rate . The percentage reduction of liver fat with weight loss was significantly associated with the corresponding decreases in VLDL – apoB-100 secretion ( r=0.67 ) and visceral fat ( r=0.84 ) . Conclusion —In patients with obesity , hepatic steatosis increases VLDL – apoB-100 secretion . Weight loss can help reduce this abnormality Obesity and physical inactivity are independent risk factors for the development of nonalcoholic fatty liver disease ( NAFLD ) . We determined the effect of endurance exercise training on hepatic lipid content and hepatic enzyme concentration in men and women .  Waist circumference ( WC ) , percent body fat ( BF ) , computed tomography ( CT ) scans for liver attenuation ( inverse relationship with hepatic lipid ) , bilirubin , alanine aminotransferase ( ALT ) , and gamma-glutamyltransferase ( GGT ) plasma concentrations were measured before and after 12 weeks of end 
    Output:
    
Meta-regression indicated a dose-response relationship between BMI reduction and decreased hepatic adiposity .
Exercise alone decreased ectopic fat but the effect was greater when combined with diet .
CONCLUSION Lifestyle interventions can reduce ectopic fat accumulation in the internal organs of overweight and obese adults .