***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: The energy density ( ED ; kcal/g ) of an entrée influences  children  's energy intake ( EI ) , but the effect of simultaneously changing both ED and portion size of an entrée on preschool children 's EI is unknown . In this within-subject crossover study , 3- to 5-year-old children ( 30 boys , 31 girls ) in a daycare facility were served a test lunch once/week for 4 weeks . The amount and type of vegetables and cheeses incorporated into the sauce of a pasta entrée were manipulated to create two versions that varied in ED by 25 % ( 1.6 or 1.2 kcal/g ) . Across the weeks , each version of the entrée was served to the children in each of two portion sizes ( 400 or 300 g ) . Lunch , consumed ad libitum , also included carrots , applesauce , and milk . Decreasing ED of the entrée by 25 % significantly ( P<0.0001 ) reduced children 's EI of the entrée by 25 % ( 63.1+/-8.3 kcal ) and EI at lunch by 17 % ( 60.7+/-8.9 kcal ) . Increasing the proportion of vegetables in the pasta entrée increased children 's vegetable intake at lunch by half of a serving of vegetables ( P<0.01 ) . Decreasing portion size of the entrée by 25 % did not significantly affect children 's total food intake or EI at lunch . Therefore , reducing the ED of a lunch entrée result ed in a reduction in  children 's EI from the entrée and from the meal in both portion size conditions . Decreasing ED by incorporating more vegetables into recipes is an effective way of reducing children 's  EI while increasing their vegetable intake BACKGROUND The results of previous studies indicated that energy density , independent of fat content , influences energy intake . In most studies , however , both fat content and energy density were lower than in typical American diets . OBJECTIVE We examined the influence of energy density on intake when fat content was above , below , or similar to the amount of fat typically consumed and when energy density was closer to that of American diets . DESIGN Lean ( n = 19 ) and obese ( n = 17 ) women consumed all meals daily in our laboratory during 6 experimental sessions . The main entrées , consumed ad libitum , were formulated to vary in fat content ( 25 % , 35 % , and 45 % of energy ) and energy density ( 5.23 kJ/g , or low energy density , and 7.32 kJ/g , or high energy density ) but to have similar palatability . RESULTS Energy density influenced energy intake across all fat contents in both lean and obese women ( P < 0.0001 ) . Women consumed less energy in the low ( 7531 kJ ) than in the high ( 9414 kJ ) energy density condition . Despite this 20 % lower energy intake , there were only small differences in hunger ( 7 % ) and fullness ( 5 % ) . Women consumed a similar volume , but not weight , of food daily across conditions . Differences in intake by weight , but not volume , occurred because for some versions of manipulated foods , weight and volume were not directly proportional . CONCLUSIONS Energy density affected energy intake across different fat contents and at levels of energy density comparable with those in typical diets . Furthermore , our findings suggest that cues related to the amount of food consumed have a greater influence on short-term intake than does the amount of energy consumed BACKGROUND The contribution of energy density ( ED ) of the total diet to increased risk of obesity  from childhood into adolescence is unclear . OBJECTIVE We assessed the relation between the ED of the diet in childhood , calculated in a number of ways , and change in adiposity from childhood to adolescence . DESIGN In a prospect i ve study , 48 children ( 30 boys , 18 girls ) were initially studied at age 6 - 8 y ( baseline ) and followed up at age 13 - 17 y.  Daily ED , energy intake , and food intake were assessed at baseline by 7-d weighed food records concurrent with estimates of total energy expenditure ( TEE ) by doubly labeled water .  ED was calculated with the use of 5 published methods . Obesity risk was defined with the use of body fat from total body water by isotope dilution . Body fat was normalized for height and expressed as fat mass index ( FMI ) . Change in adiposity was calculated as follow-up FMI minus baseline FMI . RESULTS Misreporting of energy intake at the group level at baseline was low relative to the TEE . ED of the total diet  at baseline by the 3 methods for calculating ED that excluded all or most beverages was prospect ively associated with change in FMI . However , ED of the total diet  by any of the methods was not associated with change in the percentage body fat , body mass index , or waist circumference z scores . CONCLUSION The methods used to calculate ED and to assess obesity risk lead to different conclusions about the relation between the ED of the diet in childhood and gain in fat into adolescence BACKGROUND Consuming foods low in energy density ( kcal/g ) decreases energy intake over several days , but the effectiveness of this strategy for weight loss has not been tested . OBJECTIVE The effects on weight loss of 2 strategies for reducing the energy density of the diet were compared over 1 y. DESIGN Obese women ( n = 97 ) were r and omly assigned to groups counseled either to reduce their fat intake ( RF group ) or to reduce their fat intake and increase their intake of water-rich foods , particularly fruit and vegetables ( RF+FV group ) . No goals for energy or fat intake were assigned ; the subjects were instructed to eat ad libitum amounts of food while following the principles of their diet . RESULTS After 1 y , study completers ( n = 71 ) in both groups had significant decreases in body weight ( P < 0.0001 ) . Subjects in the RF+FV group , however , had a significantly different pattern of weight loss ( P = 0.002 ) than did subjects in the RF group . After 1 y , the RF+FV group lost 7.9 + /- 0.9 kg and the RF group lost 6.4 + /- 0.9 kg . Analysis of all r and omly assigned subjects also showed a different pattern of weight loss between groups ( P = 0.021 ) . Diet records indicated that both groups had similar reductions in fat intake . The RF+FV group , however , had a lower dietary energy density than did the RF group ( P = 0.019 ) as the result of consuming a greater weight of food ( P = 0.025 ) , especially fruit and vegetables ( P = 0.037 ) . The RF+FV group also reported less hunger ( P = 0.003 ) . CONCLUSION Reducing dietary energy density , particularly by combining increased fruit and vegetable intakes with decreased fat intake , is an effective strategy for managing body weight while controlling hunger BACKGROUND Dietary energy density ( ED ) reductions are associated with energy intake ( EI ) reductions . Little is known about influences on body weight ( BW ) . OBJECTIVES We examined the effects of behavioral interventions on ED values and explored how 6-mo ED changes relate to BW . DESIGN Prehypertensive and hypertensive persons were r and omly assigned to 1 of 3 groups : the established group received an 18-session intervention implementing well-established hypertension recommendations ( eg , weight loss , sodium reduction , and physical activity ) , the established+Dietary Approaches to Stop Hypertension ( DASH ) group received an 18-session intervention also implementing the DASH diet , and the advice group received 1 session on these topics . Two 24-h dietary recalls were collected ( n=658 ) . RESULTS Each group had significant declines in EI , ED , and BW . The established and established+DASH groups had the greatest EI and BW reductions . The established+DASH group had the greatest ED reduction and the greatest increase in the weight of food consumed . When groups were combined and analyzed by ED change tertiles , participants in the highest tertile ( ie , largest ED reduction ) lost more weight ( 5.9 kg ) than did those in the middle ( 4.0 kg ) or lowest ( 2.4 kg ) tertile . Participants in the highest and middle tertiles increased the weight of food they consumed ( 300 and 80 g/d , respectively ) but decreased their EI ( 500 and 250 kcal/d ) . Conversely , those in the lowest tertile decreased the weight of food consumed ( 100 g/d ) , with little change in EI . The highest and middle tertiles had favorable changes in fruit , vegetable , vitamin , and mineral intakes . CONCLUSION Both large and modest ED reductions were associated with weight loss and improved diet quality To examine whether artificial sweeteners aid in the control of long-term food intake and body weight , we gave free-living , normal-weight subjects 1150 g soda sweetened with aspartame ( APM ) or high-fructose corn syrup ( HFCS ) per day . Relative to when no soda was given , drinking APM-sweetened soda for 3 wk significantly reduced calorie intake of both females ( n = 9 ) and males ( n = 21 ) and decreased the body weight of males but not of females . However , drinking HFCS-sweetened soda for 3 wk significantly increased the calorie intake and body weight of both sexes . Ingesting either type of soda reduced intake of sugar from the diet without affecting intake of other nutrients . Drinking large volumes of APM-sweetened soda , in contrast to drinking HFCS-sweetened soda , reduces sugar intake and thus may facilitate the control of calorie intake and body weight BACKGROUND Little is known about the long-term effects of dietary energy density ( ED ) on weight gain . OBJECTIVE The objective was to assess the long-term relation between changes in dietary ED and age-related weight gain . DESIGN We conducted a prospect i ve study of 50 026 women ( x + /- SD age : 36.5 + /- 4.6 y ) in the Nurses ' Health Study II followed from 1991 to 1999 .  Dietary ED and body weight were ascertained in 1991 , 1995 , and 1999 .  Total dietary ED  was calculated by dividing each subject 's daily energy intake ( kcal ) by the reported weight ( g ) of all foods consumed . RESULTS Dietary ED was positively correlated with saturated fat ( r = 0.16 ) , trans fat ( r = 0.15 ) , and the glycemic index ( r = 0.16 ) , but was inversely correlated with vegetable protein ( r = -0.30 ) , vegetables ( r = -0.27 ) , and fruit ( r = -0.17 ) . ED was not significantly correlated with total fat intake as a percentage of energy ( r = 0.08 ) . Women who increased their dietary ED during follow-up the most ( 5th quintile ) had a significantly greater multivariate-adjusted weight gain than did those who decreased their dietary ED ( 1st quintile ) ( 8-y time period : 6.42 kg compared with 4.57 kg ; P for trend < 0.001 ) . However , the amount of weight change over time varied considerably according to the ED values of individual foods and beverages . CONCLUSION A high dietary ED reflects a dietary pattern higher in saturated and trans fats and refined carbohydrates . Increases in dietary ED were associated with greater weight gain  among middle-aged women during 8 y of follow-up . However , public health recommendations can not be made simply on the basis of ED values of individual foods and beverages We previously increased the energy density and fat content across three diets ( factorial design ) , which led to a marked increase in energy intake in six men over 7 d while continuously resident in a whole-body indirect calorimeter . In the present study we fed the same diets to seven men who were resident in , but not confined to , a metabolic suite for 2 wk/diet . This added a component of increased physical activity . The fat , carbohydrate , and protein contents , respectively , of each diet ( as a percent of energy ) were as follows : low-fat ( LF ) , 20:67:13 ; medium-fat ( MF ) , 40:47:13 ; and high-fat ( HF ) , 60:27:13 . Energy density increased as the percent of fat in the diet increased . Energy intakes from the LF , MF , and HF diets ( 9.11 , 10.32 , and 12.78 MJ/d , respectively ) were almost identical to those in our calorimeter study ( 9.02 , 10.2 , and 12.35 MJ/d , respectively ) whereas energy expenditures ( estimated by the doubly labeled water method ) were 12.45 , 12.10 , and 11.97 MJ/d on the LF , MF and HF diets , respectively , compared with 9.48 , 9.53 , and 9.78 MJ/d , respectively , in our calorimeter study . This finding suggests that diet composition and energy expenditure combined influence energy balance in humans BACKGROUND The rising prevalence of obesity in children has been linked in part to the consumption of sugar-sweetened drinks . Our aim was to examine this relation . METHODS We enrolled 548 ethnically diverse schoolchildren ( age 11.7 years , SD 0.8 ) from public schools in four Massachusetts communities , and studied them prospect ively for 19 months from October , 1995 , to May , 1997 . We examined the association between 
    Output:
    
We posit , based on the experimental evidence , that calculating the energy density of diets by excluding drinks and including calories from drinks as a covariate in the analysis is the most valid and reliable method of testing the relationship between energy density and weight gain  in free-living humans .