***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: Mechanisms explaining the decrease in circulatory cholesterol levels after weight loss remain ill defined . The objective was to examine effects of weight loss as achieved through energy restriction upon human in vivo cholesterol bio synthesis . Six subjects ( 64 - 77 y , body mass index , 30.3 + /- 3.8 kg/m(2 ) ) were recruited into a two-phase prospect i ve clinical trial . In the first phase , subjects complied with American Heart Association ( AHA ) Step I diets for 3 mo with no change in their usual energy intake . After this weight-stable phase , subjects consumed an AHA Step I diet with a targeted reduction in energy intake of approximately 1000 kJ/d for 6 mo to achieve negative energy balance leading to weight loss . The incorporation rate of deuterium from body water into erythrocyte membrane free cholesterol over 24 h was utilized as an index of cholesterogenesis at the end of both phases . Subjects ' mean weights decreased ( P < 0.05 ) from 89.3 + /- 12.5 kg to 83.2 + /- 11.5 kg ( 6.8 + /- 2.6 % of initial body weight ) across phases . Circulating concentrations of total and LDL-cholesterol , and triglycerides also decreased ( P < 0 . 05 ) across phases . HDL-cholesterol concentrations were unchanged ( P > 0.05 ) . Cholesterol fractional synthetic rate ( FSR ) after phase 2 ( 3.04 + /- 1.90%/d ) was lower ( P < 0.05 ) than that after phase 1 ( 8 . 42 + /- 3.90%/d ) . Absolute synthesis rate ( ASR ) after phase 2 [ 0.59 + /- 0.38 g/(kg . d ) ] also was lower ( P < 0.05 ) than that after phase 1 [ 1.66 + /- 0.84 g/(kg . d ) ] . These data suggest that , in obese men , energy restriction result ing in even modest weight loss suppresses endogenous cholesterol synthesis , which contributes to a decline in circulating lipid concentrations This study examined the effects of calorie alternation and exercise on weight loss .  Moderately obese women ( 130 - 160 % of ideal body weight ) were r and omly assigned to an alternating- or constant-calorie diet with or without aerobic exercise . Both diets provided an average of 1200 kcal/d over a 12-wk period ; daily intake of subjects in the alternating-diet condition varied in a prescribed pattern from 600 to 1800 kcal/d . Exercising subjects walked 5 d/wk . All subjects participated in an intensive outpatient behavior-modification program . At the end of the study , exercised subjects had greater reductions in body weight and body fat percentage than did nonexercised subjects . The type of caloric restriction did not affect weight or fat loss . Changes in resting metabolic rate did not differ among groups . Alternating calories was neither beneficial nor detrimental as a weight-loss strategy whereas exercise was clearly beneficial in weight-loss therapy BACKGROUND Since many successful dieters regain the weight they lose , programs that teach maintenance skills are needed . We developed a maintenance program based on self-regulation theory and tested the efficacy of delivering the program face to face or over the Internet . METHODS We r and omly assigned 314 participants who had lost a mean of 19.3 kg of body weight in the previous 2 years to one of three groups : a control group , which received quarterly newsletters ( 105 participants ) , a group that received face-to-face intervention ( 105 ) , and a group that received Internet-based intervention ( 104 ) . The content of the programs in the two intervention groups was the same , emphasizing daily self-weighing and self-regulation , as was the frequency of contact with the groups . The primary outcome was weight gain over a period of 18 months . RESULTS The mean ( + /-SD ) weight gain was 2.5+/-6.7 kg in the face-to-face group , 4.7+/-8.6 kg in the Internet group , and 4.9+/-6.5 kg in the control group , with a significant difference between the face-to-face group and the control group ( 2.4 kg ; 95 % confidence interval [ CI ] , 0.002 to 10.8 ; P=0.05 ) . The proportion of participants who regained 2.3 kg or more over the 18-month period was significantly higher in the control group ( 72.4 % ) than in the face-to-face group ( 45.7 % ; absolute difference , 27 % ; 95 % CI , 14 to 39 ; P<0.001 ) or the Internet group ( 54.8 % ; absolute difference , 18 % ; 95 % CI , 5 to 30 ; P=0.008 ) . Daily self-weighing increased in both intervention groups and was associated with a decreased risk of regaining 2.3 kg or more ( P<0.001 ) . CONCLUSIONS As compared with receiving quarterly newsletters , a self-regulation program based on daily weighing improved maintenance of weight loss , particularly when delivered face to face . ( Clinical Trials.gov number , NCT00067145 [ Clinical Trials.gov ] . OBJECTIVE Conflicting recommendations are prevalent regarding the appropriateness of red meat versus white meat consumption for individuals aim ing to reduce body weight and cardiovascular disease risk . METHODS We examined changes in body weight and lipid profiles in a 12-wk , r and omized , controlled trial , in which overweight women followed a hypocaloric diet with lean beef or chicken as the primary protein source , while participating in a fitness walking program . Sedentary non-smoking females ( n = 61 ) , age 43.4 + /- 7.8 years , with body mass indexes of 32.1 + /- 3.4 kg/m(2 ) ( means + /- st and ard deviation ) , followed calculated-deficit diets ( -500 kcal daily ) and were r and omly assigned to the beef-consumption or chicken-consumption dietary group , while following a fitness walking program .  Body weight , body composition ( by hydrodensitometry ) , and blood lipid profiles were measured at baseline and 12 wk . RESULTS Weight loss was significant within ( P < 0.05 ) but similar between ( P > 0.05 ) the beef-consumption ( 5.6 + /- 0.6 kg , mean + /- st and ard error ) and the chicken-consumption ( 6.0 + /- 0.5 kg ) groups . Both groups showed significant reductions in body fat percentage ( P < 0.05 ) and total ( P < 0.05 ) and low-density lipoprotein ( P < 0.05 ) cholesterol , with no significant differences between groups . High-density lipoprotein cholesterol did not change significantly in either group . CONCLUSIONS These findings demonstrated that weight loss and improved lipid profile can be accomplished through diet and exercise , whether the dietary protein source is lean beef or chicken OBJECTIVES To compare two different very low calorie diet (VLCD)-based weight maintenance strategies . DESIGN AND SETTING A r and omized 2-year clinical trial performed at the Department of Body Composition and Metabolism , Sahlgrenska University Hospital , Sweden . SUBJECTS A total of 334 patients , body mass index ( BMI ) > 30 kg m-2 , aged 18 - 60 years . INTERVENTIONS All the patients started with 16 VLCD weeks . Subjects in the intermittent group were then scheduled to use VLCD for 2 weeks every third month , whilst patients in the on-dem and group were instructed to use VLCD whenever their body weight passed an individualized cut-off level . Irrespective of the treatment group , all the subjects were recommended a hypocaloric diet during VLCD-free periods . MAIN OUTCOME MEASURES Changes in body weight , body composition , anthropometric variables and cardiovascular risk factors . RESULTS Completers in both groups maintained highly significant weight losses after 2 years : 7.0 + /- 11.0 kg ( 6.2 + /- 9.5 % ) in the intermittent group and 9.1 + /- 9.7 kg ( 7.7 + /- 8.1 % ) in the on-dem and group ( P < 0.001 , ns between groups ) . Male completers in the on-dem and group lost significantly more weight than men in the intermittent group , 14.5 + /- 11.0 kg vs. 4.0 + /- 10.5 kg , respectively ( P < 0.01 ) . Most cardiovascular risk factors improved during the first year , whilst anthropometric measures , insulin , HDL- and LDL-cholesterol were also significantly improved after 2 years of treatment . CONCLUSION Clinical ly significant weight reductions were achieved after 2 years of VLCD-based treatment . The structure of VLCD treatment during the maintenance phase did not affect weight loss in the total study population , whilst male subjects might benefit from the VLCD on-dem and strategy CONTEXT Weight loss using low-calorie diets produces variable results , presumably due to a wide range of energy deficits and low-dietary adherence . OBJECTIVE Our objective was to quantify the relationship between dietary adherence , weight loss , and severity of caloric restriction . DESIGN AND SETTING Participants were r and omized to diet only , diet-endurance training , or diet-resistance training until body mass index ( BMI ) was less than 25 kg/m(2 ) . PARTICIPANTS Healthy overweight ( BMI 27 - 30 ) premenopausal women ( n = 141 ) were included in the study . INTERVENTIONS An 800-kcal/d(-1 ) diet was provided , and the exercise groups were engaged in three sessions per week . MAIN OUTCOMES  Dietary adherence  , calculated from total energy expenditure determined by doubly labeled water measurements and dual-energy x-ray absorptiometry body composition changes , and degree of caloric restriction were determined . RESULTS All groups had similar weight loss ( approximately 12.1 + /- 2.5 kg ) and length of time to reach target BMI ( approximately 158 + /- 70 d ) . Caloric restriction averaged 59 + /- 9 % , and adherence to diet was 73 + /- 34 % . Adherence to diet was inversely associated to days to reach target BMI ( r = -0.687 ; P < 0.01 ) and caloric restriction ( r = -0.349 ; P < 0.01 ) . Association between adherence to diet and percent weight lost as fat was positive for the diet-endurance training ( r = 0.364 ; P < 0.05 ) but negatively correlated for the diet-only group ( r = -0.387 ; P < 0.05 ) . CONCLUSIONS Dietary adherence is strongly associated with rates of weight loss and adversely affected by the severity of caloric restriction . Weight loss programs should consider moderate caloric restriction relative to estimates of energy requirements , rather than generic low-calorie diets PURPOSE To evaluate a year-long behavioral weight control program , used with and without an intermittent very-low-calorie diet ( VLCD ) in the treatment of type II diabetes mellitus . PATIENTS AND METHODS Subjects ( n = 93 ) were r and omly assigned to 50-week treatment programs that used either a balanced low-calorie diet ( LCD ) of 1,000 to 1,000 kilocalories ( kcal ) per day throughout or included 2 12-week periods of a VLCD of 400 to 500 kcal per day alternating with the balanced LCD .  Weight , glycemic control , blood pressure , and lipids were assessed at baseline , at the end of the year-long treatment , and at 2-year follow-up . RESULTS Subjects in the VLCD program lost significantly more weight than did LCD subjects at the end of the 50-week program ( 14.2 kg versus 10.5 kg ; P = 0.057 ) and remained off diabetes medication longer ( P < 0.05 ) . These benefits of the VLCD were due primarily to the first 12 weeks of the diet ; the second diet maintained , but did not increase , these effects . Subjects in both groups experienced marked improvements in glycemic control and cardiovascular risk factors over the year-long program , but attendance declined in the latter weeks of treatment and weight was regained . There was also marked recidivism in both groups in the year following treatment . CONCLUSIONS The intermittent VLCD improved weight loss and glycemic control , but these effects were quite modest and do not appear to justify the clinical use of an intermittent VLCD . Moreover , lengthening treatment to a full year did not prevent relapse . Thus , further research is needed to develop a successful approach to long-term weight control OBJECTIVE : To investigate the effectiveness of intensive innovative methods for implementing dietary prescriptions on weight management and glycaemic control in overweight men with Type II diabetes . DESIGN : A r and omised clinical trial with a 12-week intervention period — three isocaloric dietary intervention groups ( intermittent energy restriction , pre-portioned meals and self-selected meals ) each with weekly dietitian contact — and a follow-up visit after 18 months . SUBJECTS : A total of 51 men with Type II diabetes ( mean age 54 y , mean body mass index ( BMI ) 31.7 kg/m2 ) .  MEASUREMENTS : Weight , body composition , waist circumference 
    Output:
    
The effects of intermittent energy restriction in the long term remain unclear .
Blood lipid concentrations , glucose , and insulin were not altered by intermittent energy expenditure in values greater than those seen with continuous energy restriction