***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: To study the impact of diet and exercise and the combination thereof on cardiovascular risk factors , 157 healthy men aged 35 - 60 years ( mean + /- S.D. ; 46.2 + /- 5.0 ) with slightly to moderately raised cardiovascular risk factors , were r and omized to 4 groups , diet ( D , n = 40 ) , exercise ( E , n = 39 ) , diet plus exercise ( DE , n = 39 ) , and no active intervention ( controls ( C , n = 39 ) ) , and investigated at baseline and after 6 months . BMI was significantly reduced in Groups E and DE ( mean difference and 95 % confidence intervals ( CI ) , -0.3 ( -0.5 , -0.01 ) and -0.6 ( -0.9 , -0.3 ) kg/m2 , respectively ) . Waist circumference was reduced in all 3 intervention groups ( D , E , and DE ) , -1.3 ( -2.5 , -0.1 ) , -2.2 ( -3.2 , -1.3 ) and -3.0 ( -3.9 , -2.0 ) cm , but not in the control group . Blood pressure ( BP ) was reduced in all 3 intervention groups , systolic BP 4 - 7 mmHg and diastolic BP 2 - 6 mmHg . Serum cholesterol was reduced in Group DE , -0.45 ( -0.77 , -0.13 ) mmol/l . VLDL-cholesterol was reduced in Groups E and DE , -0.14 ( -0.26 , -0.03 ) and -0.09 ( -0.18 , -0.01 ) mmol/l , whereas LDL-cholesterol was reduced in Groups D and DE -0.30 ( -0.54 , -0.06 ) and -0.35 ( -0.64 , -0.05 ) mmol/l . In contrast , neither HDL-cholesterol nor serum triglycerides were influenced by the interventions . According to the coronary risk profile derived from the Framingham study , all 3 intervention groups ( D , E , and DE ) significantly reduced their estimated 10-year risk ( -13 , -12 , and -14 % , respectively ) . We conclude that even with rather moderate changes in diet and exercise , several important cardiovascular risk factors can be affected and that diet and exercise were about equally effective in reducing cardiovascular risk Thirty obese women were r and omly assigned to either 40 % [ severe energy restriction ( SER ) ] or 70 % [ moderate energy restriction ( MER ) ] of their maintenance energy requirements and to no exercise , aerobic exercise ( walking ) , or aerobic exercise plus circuit weight training .  Body composition by hydrostatic weighing and energy expenditure by indirect calorimetry were measured at 0 , 3 , and 6 mo . In addition , we developed a deficit-efficiency factor ( DEF ) , calculated as body energy loss/dietary energy deficit , to attempt to quantify the effectiveness of the weight-reduction interventions . Subjects in the SER group lost more weight ( mean + /- SE : 15.1 + /- 1.4 vs 10.8 + /- 1.0 kg ) , fat ( 11.7 + /- 1.1 vs 8.3 + /- 0.6 kg ) , and fat-free mass ( 2.8 + /- 0.3 vs 1.8 + /- 0.3 kg ) than the MER group ( P < or = 0.05 ) . However , the overall DEF was greatest in the MER group ( 0.80 + /- 0.07 ) compared with the SER group ( 0.52 + /- 0.05 ; P < or = 0.01 ) . Exercise had no significant effect . This study demonstrates that MER may offer an advantage over SER because it produces a greater energy loss relative to energy deficit The National Weight Control Registry ( NWCR ) is , to the best of our knowledge , the largest study of individuals successful at long-term maintenance of weight loss . Despite extensive histories of overweight , the 629 women and 155 men in the registry lost an average of 30 kg and maintained a required minimum weight loss of 13.6 kg for 5 y. A little over one-half of the sample lost weight through formal programs ; the remainder lost weight on their own . Both groups reported having used both diet and exercise to lose weight and nearly 77 % of the sample reported that a triggering event had preceded their successful weight loss . Mean ( + /-SD ) current consumption reported by registry members was 5778 + /- 2200 kJ/d , with 24 + /- 9 % of energy from fat , Members also appear to be highly active : they reported expending approximately 11830 kJ/wk through physical activity . Surprisingly , 42 % of the sample reported that maintaining their weight loss was less difficult than losing weight . Nearly all registry members indicated that weight loss led to improvements in their level of energy , physical mobility , general mood , self-confidence , and physical health . In summary , the NWCR identified a large sample of individuals who were highly successful at maintaining weight loss . Future prospect i ve studies will determine variables that predict continued maintenance of weight loss BACKGROUND Overweight and inactivity are associated with impaired glucose tolerance , reduced insulin sensitivity , and diabetes . Few controlled trials have assessed the independent and combined effects of energy restriction and exercise on the prevention of these conditions . OBJECTIVE The objective was to evaluate the independent and additive effects of 16 wk of energy restriction and exercise on glucose and insulin concentrations . DESIGN Sixty nonsmoking , overweight , sedentary men aged 20 - 50 y were r and omly assigned to either maintain or restrict their energy intake ( 4186 - 6279 kJ/d ) . Within each of these arms , the subjects were further r and omly assigned to either a light-intensity ( control ) or a vigorous-intensity exercise program for 30 min 3 times/wk . RESULTS Fifty-one subjects completed the study .  Maximal oxygen uptake increased ( approximately 24 % ; P < 0.001 ) with vigorous but not with light exercise . Significant weight loss was observed with energy restriction ( x : 10.12 kg ; 95 % CI : 8.02 , 12.22 kg ; P < 0.001 ) but not with exercise . Vigorous exercise reduced fasting glucose and glucose and insulin areas under the curve ( AUCs ) by 13 % ( P = 0.01 ) and 20 % ( P = 0.02 ) , respectively . Exercise effects were independent of weight change . Energy restriction result ed in a 40 % reduction in the insulin AUC ( P = 0.01 ) . Vigorous exercise and energy restriction were additive in reducing the insulin AUC . CONCLUSIONS Energy restriction and vigorous exercise independently and additively reduce glucose and insulin concentrations in response to an oral-glucose-tolerance test . Both of these lifestyle interventions provide a potent strategy that should be an integral part of any program to reduce the risk of impaired glucose tolerance , insulin resistance , and diabetes in overweight and sedentary persons The effects of caloric restriction and exercise on body composition , resting metabolic rate ( RMR ) , and maximal oxygen uptake ( VO2 max ) were studied for 16 wk in 26 premenopausal obese women .  Exercise ( X ) vs nonexercise ( NX ) was crossed with a low-fat , ad libitum-carbohydrate ( AL ) diet vs a restricted ( R ) ( 800 kcal ) low-fat , high-carbohydrate diet in a 2 x 2 factorial design . Subjects were r and omly assigned to one of the four treatment groups . Body-weight and percent-fat losses were significant ( p less than 0.05 ) in all groups but greater in subjects assigned to the R diet ( p less than 0.05 ) and /or X ( p less than 0.10 ) groups . Exercise increased ( p less than 0.01 ) VO2 max but neither exercise nor diet influenced fat-free mass or RMR ( kcal.m-2.h-1 ) , both of which remained unchanged over time . A program similar to that followed by the ALX group is recommended for long-term weight control and overall health This study examined the interaction of 2 diets ( high protein , reduced carbohydrates vs. low protein , high carbohydrates ) with exercise on body composition and blood lipids in women ( n = 48 , approximately 46 y old , BMI = 33 kg/m(2 ) ) during weight loss . The study was a 4-mo weight loss trial using a 2 x 2 block design ( Diet x Exercise ) . Diets were equal in total energy ( 7.1 MJ/d ) and lipids ( approximately 30 % energy intake ) but differed in protein content and the ratio of carbohydrate : protein at 1.6 g/(kg . d ) and < 1.5 ( PRO group ) vs. 0.8 g/(kg . d ) and > 3.5 ( CHO group ) , respectively . Exercise comparisons were lifestyle activity ( control ) vs. a supervised exercise program ( EX : 5 d/wk walking and 2 d/wk resistance training ) . Subjects in the PRO and PRO + EX groups lost more total weight and fat mass and tended to lose less lean mass ( P = 0.10 ) than the CHO and CHO + EX groups . Exercise increased loss of body fat and preserved lean mass . The combined effects of diet and exercise were additive for improving body composition . Serum lipid profiles improved in all groups , but changes varied among diet treatments . Subjects in the CHO groups had larger reductions in total cholesterol and LDL cholesterol , whereas subjects in the PRO groups had greater reductions in triacylglycerol and maintained higher concentrations of HDL cholesterol . This study demonstrated that a diet with higher protein and reduced carbohydrates combined with exercise additively improved body composition during weight loss , whereas the effects on blood lipids differed between diet treatments Exercise is frequently identified as a predictor of weight maintenance after elective weight loss in retrospective studies of treatments for obesity . We conducted a prospect i ve study to test whether physical activity measured soon after weight loss predicted weight maintenance and to determine how much physical activity was required to optimize maintenance . Thirty-two women [ mean ( + /- SD ) age , 38 + /- 7 y ; body mass index ( in kg/m2 ) , 24 + /- 3 ] were recruited through local advertising within 3 mo of reaching their target for weight loss ( 23 + /- 9 kg ) .  Total energy expenditure ( TEE ) was measured by the doubly labeled water method .  Postabsorptive resting metabolic rate ( RMR ) and postpr and ial RMR [ expressed as thermic effect of a meal ( TEM ) ] were measured by respiratory gas exchange . Women in the physically active group ( ratio of TEE to RMR = 1.89 + /- 0.08 ) gained 2.5 + /- 3.1 kg during the 12 mo after reaching their target for weight loss , moderately active women ( TEE : RMR = 1.64 + /- 0.05 ) gained 9.9 + /- 10.5 kg , and sedentary women ( TEE : RMR = 1.44 + /- 0.08 ) gained 7.0 + /- 5.9 kg ( P < 0.01 ) . Retrospective analyses of weight regain as a function of energy expended in physical activity indicated a threshold for weight maintenance of 47 kJ x kg body wt(-1 ) x d(-1 ) . This corresponds to an average of 80 min/d of moderate activity or 35 min/d of vigorous activity added to a sedentary lifestyle Obese women who regained weight after successful weight reduction ( relapsers , n = 44 ) ; formerly obese , average-weight women who maintained weight loss ( maintainers , n = 30 ) ; and women who had always remained at the same average , nonobese weight ( control subjects , n = 34 ) were interviewed . Most maintainers ( 90 % ) and control subjects ( 82 % ) exercised regularly , were conscious of their behaviors , used available social support ( 70 % and 80 % , respectively ) , confronted problems directly ( 95 % and 60 % , respectively ) , and used personally developed strategies to help themselves . Few relapsers exercised ( 34 % ) , most ate unconsciously in response to emotions ( 70 % ) , few used available social support ( 38 % ) , and few confronted problems directly ( 10 % ) . These findings suggest the advisability of development and prospect i ve evaluation of individualized treatment programs design ed to enhance exercise , coping skills , and social support The effects of severe energy restriction alone ( 2.0 MJ/d for 4 wk and subsequently 3.5 MJ/d for 4 wk ) or energy restriction plus moderate exercise on energy balance were studied in 20 healthy obese women . Subjects aged 25 - 50 y were matched on the basis of body mass index and percentage body fat and r and omly assigned to diet alone ( D ) or diet and exercise ( DE ) for 8 wk . DE result ed in a significantly increased loss of fat mass compared with D ( 7.8 + /- 0.8 compared with 5.5 + /- 0.8 kg ; P < 0.05 ) . The average daily metabolic rate measured with doubly labeled water decreased with both treatments , with no differences between the treatments . Energy balance data show that the DE treatment result ed in a significantly greater energy deficit than the D treatment . The relative contribution of fat to energy expenditure during exercise was significantly enhanced by DE treatment whereas it did not change after D. The energy expended on physical activity was not changed at the end of both treatments , with no differences between the two groups . The unchanged energy exp 
    Output:
    
In prospect i ve studies that prescribed high levels of exercise , enrolled individuals achieved substantially greater weight loss — comparable to that obtained after similar energy deficits were produced by caloric restriction .
RCTs examining exercise and its effect on weight-loss maintenance demonstrated mixed results ; however , weight maintenance interventions were usually of limited duration and long-term adherence to exercise was problematic .
Epidemiologic , cross-sectional , and prospect i ve correlation studies suggest an essential role for physical activity in weight-loss maintenance , and post hoc analysis of prospect i ve trials shows a clear dose – response relationship between physical activity and weight maintenance .