Review
International Journal of Obesity (2007) 31, 743–750. doi:10.1038/sj.ijo.0803483; published online 31 October 2006
Changes in fat-free mass during significant weight loss: a systematic review
T B Chaston1, J B Dixon1 and P E O'Brien1
1Australian Centre for Obesity Research and Education, Monash University, Monash Medical School, The Alfred Hospital, Melbourne, Victoria, Australia
Correspondence: Dr JB Dixon, Australian Centre for Obesity Research and Education, Monash University, Monash Medical School, The Alfred Hospital, Commercial Road, Melbourne, Victoria 3004, Australia. E-mail: john.dixon@med.monash.edu.au
Received 22 May 2006; Revised 23 August 2006; Accepted 31 August 2006; Published online 31 October 2006.
Abstract
Objective:
To identify the proportion of weight lost as fat-free mass (FFM) by various weight loss interventions.
Methods:
Medline and Embase were systematically searched for reliable measurements of FFM before and after weight loss of >10 kg and eligible data were pooled. In a fixed effect model of % FFM loss/weight loss (%FFML), linear regression analysis was used to determine the influence of degree of caloric restriction, exercise, magnitude of weight loss, initial body mass index (BMI) and type of surgery.
Results:
Data were included from 26 cohorts treated with dietary and behavioral interventions and 29 cohorts of bariatric surgery patients. The degree of caloric restriction was positively associated with %FFML (r 2=0.31, P=0.006) and in three randomized controlled trials exercise was shown to decrease %FFML. Compared with laparoscopic adjustable gastric banding (LAGB), biliopancreatic diversion (BPD) and roux en Y gastric bypass (RYGB) caused greater loge (natural log) %FFML (r 2=0.453, P<0.001). Differences in loge %FFML between surgical procedures were independent of initial BMI and magnitude of weight loss.
Conclusions:
The degree of caloric restriction, exercise and rate of weight loss influence the proportion of weight lost as FFM after non-surgical interventions. For surgical interventions, BPD and RYGB result in greater %FFML than LAGB.
Keywords:
body composition, dual X-ray absorptiometry, under water weighing, total body water
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RESEARCH
Changes in fat-free mass during significant weight loss: a systematic review
International Journal of Obesity Original Article
