***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 Higher protein diets are promoted for effective weight loss . Striated tissues in omnivorous diets contain high- quality protein , but limited data exist regarding their effects on bone . METHODS To examine the effects of energy restriction-induced weight loss with higher protein omnivorous diets versus lower protein vegetarian diets on  bone mineral density  in overweight postmenopausal women , two r and omized controlled feeding studies were conducted . In Study 1 , 28 women consumed 750 kcal/day energy deficit diets with 18 % energy from protein via lacto-ovo vegetarian sources ( normal protein , n = 15 ) or 30 % energy from protein with 40 % of protein from lean pork ( higher protein , n = 13 , omnivorous ) for 12 weeks . In Study 2 , 54 women consumed their habitual diet ( control , n = 11 ) or 1,250 kcal/day diets with 16 % energy from nonmeat protein sources ( n = 14 ) or 26 % energy from protein , including chicken ( n = 15 ) or beef ( n = 14 ) for 9 weeks . RESULTS Study 1 : With weight loss ( normal protein -11.2 % , higher protein -10.1 % ) , bone mineral density was not significantly changed in normal protein ( -0.003 ± 0.003 g/cm(2 ) , -0.3 % ) but decreased in higher protein ( -0.0167 ± 0.004 g/cm(2 ) , -1 . 4 % , group-by-time p < .05 ) . Study 2 : The control , nonmeat , chicken , and beef groups lost 1.5 % , 7.7 % , 10.4 % , and 8.1 % weight and 0.0 % , 0.4 % , 1.1 % , and 1.4 % bone mineral density , respectively . The change of bone mineral density was significant for chicken and beef compared with the control ( group-by-time , p < .05 ) . Markers of calcium metabolism and bone homeostasis in blood and urine were not changed over time or differentially affected by diet . CONCLUSION Consumption of higher protein omnivorous diets promoted decreased bone mineral density after weight loss in overweight postmenopausal women Bone turnover is increased during weight loss in postmenopausal women and can be suppressed with calcium supplementation . In this study , we assessed the influence of energy restriction with and without calcium supplementation ( 1 g/day ) in premenopausal women . Thirty-eight obese premenopausal women ( body mass index [ BMI ] of 35.0 + /- 3.9 kg/m2 ) completed a 6-month study of either moderate weight loss or weight maintenance . During weight loss , women were r and omly assigned to either a calcium supplementation ( n = 14 ) or placebo group ( n = 14 ) and lost 7.5 + /- 2.5 % of their body weight . The control group of women ( n = 10 ) maintained their body weight . Total body and lumbar bone mineral density ( LBMD ) and content were measured by dual-energy X-ray absorptiometry ( DXA ) at baseline and after weight loss . Throughout the study , blood and urine sample s were collected to measure bone turnover markers and hormones . During moderate energy restriction , dietary calcium intake decreased ( p < 0.05 ) and the bone resorption marker deoxypyridinoline ( DPD ) increased slightly ( p < or = 0.05 ) without evidence of bone loss .  Calcium supplementation during weight loss tended to increase lumbar BMD by 1.7 % ( p = 0.05 ) compared with the placebo or weight maintenance groups . In contrast to our previous findings in postmenopausal women , premenopausal obese women who consume a low calcium diet do not lose bone over a 6-month period , whether their weight is stable or decreasing moderately Bone loss accompanies a diet-induced weight loss and could be prevented with a combination of exercises . This study was conducted to examine the effects of additional resistance training during diet-induced weight loss on whole-body and selected regional bone mineral density ( BMD ) . The participants of a 14-week weight-loss study were 42 overweight premenopausal Japanese women who were r and omly placed in either a  diet-only group  ( D ; n = 21 ) or a diet plus resistance training group  ( DR ; n = 21 ) . Whole-body BMD and body composition , lumbar spine BMD , and 1/3 radial BMD were measured by dual-energy X-ray absorptiometry before and after the intervention . Bone formation and resorption markers were also measured . Thirty-five participants ( 83 % ) completed the study . Individuals in groups D ( n = 17 ) and DR ( n = 18 ) lost 6.2 ± 3.5 kg and 8.6 ± 3.6 kg body weight , respectively . Reductions in percentage fat mass and fat mass in group DR were significantly greater than in group D ; lean mass decreased significantly in both groups . The effect of time on whole-body BMD was significant ( −0.3 % ) ; however , whole-body bone mineral content , lumbar spine BMD , and 1/3 radial BMD remained unchanged . There were no significant timeby-group interactions in the whole-body and regional BMD and bone markers . These results suggest that additional resistance training during weight loss has no effect on BMD in overweight premenopausal Japanese women . Further long-term studies with large numbers of subjects are needed Weight loss causes  bone mineral loss .  Higher protein diets continue to be criticized for further potential harmful bone effects , including elevated urinary calcium , but may promote bone health if protein sources include dairy . Overweight middle-aged subjects ( n = 130 , 59 males ) were r and omized to a diet providing 1.4 g.kg(-1).d(-1 ) protein and 3 daily servings of dairy ( PRO ) or 0.8 g.kg(-1).d(-1 ) protein and 2 daily servings of dairy ( CARB ) for 4 mo of weight loss plus 8 mo of weight maintenance . Diets prescribed 6276 kJ/d for females and 7113 kJ/d for males . Bone mineral content and density ( BMD ) for whole body ( WB ) , lumbar spine ( LS ) and total hip ( TH ) were measured using dual X-ray absorptiometry , and dietary intake using 3-d weighed food records . Urinary calcium was measured using 24-h collection at 0 and 8 mo for a sub sample ( n = 42 ) . Participants lost body weight ( mean , 95 % CI ) of 8.2 % ( 7.5 - 8.9 % ) at 4 mo , 10.6 % ( 9.5 - 11.8 % ) at 8 mo , and 10.5 % ( 8.9 - 12.0 % ) at 12 mo without differences between groups at any time ( P = 0.64 ) . At 12 mo , PRO BMD was higher by 1.6 % ( 0.3 - 3.0 % ) at WB , 2.1 % ( 0.6 - 3.7 % ) at LS , and 1.4 % ( 0.2 - 2.5 % ) at TH compared with  CARB  .  PRO calcium intake was higher ( PRO : 1140 + /- 58 mg/d , CARB : 766 + /- 46 ; P < 0.01 ) , as was urinary calcium ( PRO : 163 + /- 15 mg/d , CARB : 100 + /- 9.2 ; P < 0.01 ) . A reduced-energy diet supplying 1.4 g.kg(-1).d(-1 ) protein and 3 dairy servings increased urinary calcium excretion but provided improved calcium intake and attenuated bone loss over 4 mo of weight loss and 8 additional mo of weight maintenance BACKGROUND Weight loss is associated with bone loss , but this has not been examined in overweight premenopausal women . OBJECTIVE The aim of this study was to assess whether overweight premenopausal women lose bone with moderate weight loss at recommended or higher than recommended calcium intakes . DESIGN Overweight premenopausal women [ n = 44 ; x ( + /-SD ) age : 38 + /- 6.4 y ; body mass index ( BMI ): 27.7 + /- 2.1 kg/m(2 ) ] were r and omly assigned to either a normal ( 1 g/d ) or high ( 1.8 g/d ) calcium intake during 6 mo of energy restriction [ weight loss ( WL ) groups ] or were recruited for weight maintenance at 1 g Ca/d intake .  Regional bone mineral density and content were measured by dual-energy X-ray absorptiometry , and markers of bone turnover were measured before and after weight loss . True fractional calcium absorption ( TFCA ) was measured at baseline and during caloric restriction by using a dual-stable calcium isotope method . RESULTS The WL groups lost 7.2 + /- 3.3 % of initial body weight . No significant decrease in BMD or rise in bone turnover was observed with weight loss at normal or high calcium intake . The group that consumed high calcium showed a strong relation ( r = 0.71 ) between increased femoral neck bone mineral density and increased serum 25-hydroxyvitamin D. No significant effect of weight loss on TFCA was observed , and the total calcium absorbed was adequate at 238 + /- 81 and 310 + /- 91 mg/d for the normal- and high-calcium WL groups , respectively . CONCLUSION Overweight premenopausal women do not lose bone during weight loss at the recommended calcium intake , which may be explained by sufficient amounts of absorbed calcium 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 Weight loss induces bone resorption and this can be attenuated by calcium supplementation . Protein-rich diets were recently associated with favorable effects on bone density , although this remains controversial . We hypothesized that a diet high in calcium and protein would minimize bone resorption during weight loss compared with a lower calcium , protein-rich diet . The effects of dietary calcium in high protein diets on calcium excretion and bone metabolism were examined in overweight adults ( n = 50 , BMI 33.4 + /- 2.1 kg/m(2 ) ) during 12 wk of energy restriction followed by 4 wk of energy balance . Subjects were r and omly assigned to isoenergetic diets ( 5.5 MJ/d , 34 % energy from protein , 41 % carbohydrate , 24 % fat ) high in either dairy protein ( DP , 2400 mg Ca/d ) or mixed protein sources ( MP , 500 mg Ca/d ) . During energy restriction , weight loss was 10 % ( -9.7 + /- 3.8 kg , P < 0.01 ) , and 24-h urinary calcium excretion decreased independently of diet ( -1.09 + /- 0.23 mmol/d , P < 0.01 ) . By wk 16 , the MP diet group had a 40 % greater increase in deoxypyridinoline ( bone resorption marker ) than the DP diet group ( P = 0.008 ) . Osteocalcin ( bone formation marker ) increased from wk 0 to 16 in only the MP diet group [ + 2.16 + /- 0.63 micro g/L ( + 0.63 + /- 0.11nmol/L ) , P = 0.001 ] . In conclusion , weight loss was associated with increased bone resorption , yet the DP diet had a modest advantage over the MP diet by minimizing overall turnover . Combined with reduced urinary calcium excretion , this suggests that a high-protein , calcium-replete diet may protect against bone loss during weight reduction BACKGROUND Overweight and obesity are increasing in young adults . However , moderate energy restriction aim ed at lowering body weight may promote bone turnover and bone loss . Inclusion of fish or fish oils in a weight-loss diet may attenuate these adverse skelet 
    Output:
    
These data show that in overweight and obese individuals , a single diet-induced weight-loss intervention induces a small decrease in total hip BMD , but not lumbar spine BMD .
This decrease is small in comparison to known metabolic benefits of losing excess weight