***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: BACKGROUND Recommending increased physical activity facilitates long-term weight loss , but the optimal level of physical activity to recommend is unknown . OBJECTIVE The objective of the study was to evaluate the efficacy for long-term weight loss of recommendations for much higher physical activity than those normally used in behavioral treatments . DESIGN Overweight men and women ( n = 202 ) were r and omly assigned to either a st and ard behavior therapy ( SBT ) for obesity , incorporating an energy expenditure ( EE ) goal of 1000 kcal/wk , or to a high physical activity ( HPA ) treatment , in which the goal was an EE of 2500 kcal/wk . To help HPA treatment group participants achieve this high exercise goal , their treatment included encouragement to recruit 1 - 3 exercise partners into the study , personal counseling from an exercise coach , and small monetary incentives . RESULTS The HPA treatment group reported achieving higher mean ( + /- SD ) physical activity levels than did the SBT group at 6 mo ( EE of 2399 + /- 1571 kcal/wk compared with 1837 + /- 1431 kcal/wk ) , 12 mo ( EE of 2249 + /- 1751 kcal/wk compared with 1565 + /- 1309 kcal/wk ) , and 18 mo ( EE of 2317 + /- 1854 kcal/wk compared with 1629 + /- 1483 kcal/wk ) ( all P < 0.01 ) . Mean ( + /- SEM ) cumulative weight losses at 6 , 12 , and 18 mo in the HPA treatment group were 9.0 + /- 7.1 , 8.5 + /- 7.9 , and 6.7 + /- 8.1 kg , respectively . In the SBT group , the corresponding weight losses were 8.1 + /- 7.4 , 6.1 + /- 8.8 , and 4.1 + /- 7.3 kg , respectively . Between-group differences in weight loss were significant at 12 and 18 mo . CONCLUSION These results suggest that recommendations of higher levels of physical activity ( EE of 2500 kcal/wk ) promote long-term weight loss better than do conventional recommendations 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 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 A definitive model for predicting absolute risk of coronary heart disease ( CHD ) in male and female people with Type II diabetes is not yet available . This paper provides an equation for estimating the risk of new CHD events in people with Type II diabetes , based on data from 4540 U.K. Prospect i ve Diabetes Study male and female patients . Unlike previously published risk equations , the model is diabetes-specific and incorporates  glycaemia , systolic blood pressure and lipid levels  as risk factors , in addition to age , sex , ethnic group , smoking status and time since diagnosis of diabetes . All variables included in the final model were statistically significant ( P<0.001 , except smoking for which P=0.0013 ) in likelihood ratio testing . This model provides the estimates of CHD risk required by current guidelines for the primary prevention of CHD in Type II diabetes In 1997 , the World Health Organization published a l and mark document recognizing obesity as a worldwide disease that poses a serious threat to public health ( 1 ) . Persons who are overweight or obese have substantially increased risk for morbidity from numerous chronic disorders , such as diabetes ( 2 , 3 ) , hypertension ( 4 , 5 ) , and cardiovascular disease ( 6 , 7 ) . Obesity-related health risk is greater when excess fat is deposited in the abdomen region because this phenotype is a stronger predictor of cardiovascular disease and type 2 diabetes mellitus than general obesity is ( 8 - 11 ) . This may be partially explained by excess accumulation of visceral fat , an independent correlate of insulin resistance ( 9 - 11 ) and dyslipidemia ( 8 , 9 ) . These observations highlight the need to identify appropriate treatment strategies to prevent and reduce obesity and suggest that the effectiveness of these treatments would be enhanced if abdominal obesity , particularly visceral fat , was substantially reduced . Diet restriction remains the most common method of obesity reduction ( 12 ) . Despite the observation that low levels of physical activity are a major cause of obesity ( 13 ) , increased physical activity alone is not thought to be a useful strategy for obesity reduction . Some reports have suggested that physical activity in obese adults results in only modest weight loss ( approximately 1 to 2 kg ) independent of the effects of diet restriction ( 14 ) . However , these conclusions are drawn from studies in which individual energy intake and expenditure were not rigorously controlled or accurately measured ( 15 - 17 ) . Moreover , in most studies , the negative energy balance induced by exercise was modest enough that substantial weight loss was not expected ( 15 - 17 ) . Currently , no compelling evidence supports the observation that exercise alone is not a useful method for reducing total or abdominal obesity . It is well known that a single exercise session is associated with a significant improvement in insulin-stimulated glucose uptake ( 18 , 19 ) . It is also clear that weight loss is associated with an improvement in insulin action ( 20 - 24 ) . It is unclear , however , whether regular exercise improves glucose metabolism after the short-term effects of exercise and changes in body fat distribution are considered . Segal and colleagues ( 25 ) controlled for the confounding effect of the last exercise session and body composition changes and found that exercise had no independent effect on insulin sensitivity ( 25 ) . Given the established importance of insulin resistance as an antecedent to both cardiovascular disease and type 2 diabetes mellitus ( 26 ) , it is important to clarify whether exercise improves insulin action independent of fat loss . We performed a r and omized , controlled trial to determine the independent effect of diet-induced or exercise-induced weight loss on obesity and insulin resistance in moderately obese men . We also evaluated whether exercise without weight loss was associated with reductions in abdominal obesity and insulin resistance . Methods Participants Participants were recruited from Kingston , Ontario , Canada , a typical suburban region , through the general media . We selected men with a body mass index greater than 27 kg/m2 and a waist circumference greater than 100 cm whose weight had been stable ( 2 kg ) for 6 months before study entry . Participants were nonsmokers who consumed an average of fewer than two alcoholic beverages per day , had a sedentary lifestyle , and took no medications known to affect the principal outcome measures . All participants had a preparticipation medical examination that included screening for normal glucose tolerance and plasma lipid profile . A computer program was used to r and omly assign eligible men to one of the following four groups : control , diet-induced weight loss , exercise-induced weight loss , and exercise without weight loss ( Figure 1 ) . Of the 101 participants who were r and omly assigned to groups , 34 chose not to participate because they were dissatisfied with their assigned group , 5 were diabetic or dyslipidemic , and 3 were relocated because of job transfers . Those who chose not to participate and those who completed the trial were similar with regard to anthropometric variables . In addition , those who completed the trial were similar to those who did not in each group ( P > 0.10 ) . Baseline characteristics among groups were similar for all participants ( Table 1 ) . All participants gave fully informed written consent . The study was conducted in accordance with the ethical guidelines of Queen 's University . The participants did not receive monetary compensation . Figure 1 . Flow of participants through the study . Table 1 . Selected Anthropometric , Magnetic Resonance Imaging , and Metabolic Variables before Treatment and 3 Months after Treatment Diet and Exercise Regimen During the baseline period , daily energy requirements for all participants were determined by estimating resting energy expenditure and multiplying the obtained value by a factor of 1.5 ( 27 ) . All participants followed a weight maintenance diet ( 55 % to 60 % carbohydrate , 15 % to 20 % protein , and 20 % to 25 % fat ) for a 4- to 5-week baseline period . During this period , body weight was monitored to determine the accuracy of the prescribed energy requirement , which was adjusted accordingly to maintain body weight . Controls were asked to maintain body weight throughout the 12-week treatment period . Participants in the diet-induced weight loss group were asked to reduce the isocaloric diet by 700 kcal/d during the treatment period to achieve a weekly weight loss of approximately 0.6 kg . To lose the same amount of weight , participants in the exercise-induced weight loss group were asked to maintain the isocaloric diet for the duration of the treatment period and to perform exercise that expended 700 kcal/d . Participants assigned to exercise without weight loss were asked to maintain body weight . Therefore , they consumed enough calories to compensate for the energy expended during the daily exercise sessions ( approximately 700 kcal ) . At the end of the treatment period , isocaloric requirements were determined and prescribed for a 2-week weight stabilization period . All participants were free-living and consumed self-selected foods .  No vitamins or other nutritional supplements were prescribed . Each person participated in a series of weekly 1-hour seminars in which a dietitian taught proper food selection and preparation . Participants were told that the composition of the maintenance and energy-reduced diets should be approximately 55 % to 60 % carbohydrate , 15 % to 20 % protein , and 20 % to 25 % fat . Participants kept and analyzed daily , detailed food records for the duration of the study period ( approximately 20 weeks ) ; the study dietitian also review ed these records . For the 2-week period during which doubly labeled water measurements were acquired ( weeks 6 and 7 ) , the diet records were analyzed by using a computerized program ( Food Processor , Esha Research , Salem , Oregon ) . Participants in both exercise groups performed daily exercise ( brisk walking or light jogging ) on a motorized treadmill for the duration of the 12-week trial . The length of each exercise session was determined by the time required to expend 700 kcal . Participants were asked to exercise at an intensity not greater than 70 % of their peak oxygen uptake ( Vo 2 ) ( approximately 80 % of maximal heart rate ) . Energy expenditure was determined by using the heart rate and oxygen consumption data that were obtained from the pretreatment grade d exercise test and were adjusted according to the results of two subsequent tests performed at weeks 4 and 8 . During each session , heart rate was monitored every 5 minutes by using an automated heart rate monitor ( Polar Oy , Kempele , Finl and ) . All exercise sessions were by appointment and were supervised . Peak Vo 2 was determined by using a grade d treadmill test and st and 
    Output:
    
Therefore , there is firm and consistent evidence that programs of increased physical activity  and modest weight loss reduce the incidence of type 2 diabetes in individuals with IGT .
In contrast , postintervention body weight did not differ between the exercise and control groups .
Meta-regression confirmed that the beneficial effect of exercise on A1C