title: Fat-free mass loss generated with weight loss in overweight and obese adults: What may we expect?
abstract: There is concern that intentional weight loss may generate excessive loss of fat-free mass (FFM). Idealists target minimal loss of FFM, while others consider that FFM loss of up to 25% of weight loss is acceptable. In a cross-sectional study of 275 weight-stable, overweight or obese adults, we used whole-body dual-energy X-ray absorptiometry to measure FFM. A range of models was used to estimate the expected ΔFFM/Δweight ratio required to attain the body composition of a weight-stable individual at a lower body mass index (BMI). Higher BMI was associated linearly with higher FFM in men and women. Proportional ΔFFM/Δweight was influenced by sex, BMI and age. Direct scatter plot analysis, quadratic curve fit modelling and linear FFM-BMI modelling provided similar estimates for each model of ΔFFM/Δweight ratio, with 40% for men and 33% for women. These results show that the 25% rule is inappropriate and our estimates are higher than those generally reported after intentional weight loss indicating favourable preservation of FFM.
authors.affiliation: Clinical Obesity Research, Baker IDI Heart & Diabetes Institute, Melbourne, Australia; Primary Care Research Unit, Monash University, Melbourne, Australia.
authors.forename: J B
authors.initials: JB
authors.lastname: Dixon
authors.forename: E A
authors.initials: EA
authors.lastname: Lambert
authors.forename: M
authors.initials: M
authors.lastname: Grima
authors.forename: T
authors.initials: T
authors.lastname: Rice
authors.forename: G W
authors.initials: GW
authors.lastname: Lambert
authors.forename: N E
authors.initials: NE
authors.lastname: Straznicky
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D001823:Body Composition; D015992:Body Mass Index; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D024510:Muscle Development; D009133:Muscular Atrophy / Q000000981:diagnostic imaging / Q000208:ethnology / Q000209:etiology / Q000517:prevention & control*; D009749:Nutrition Surveys; D009765:Obesity / Q000000981:diagnostic imaging / Q000208:ethnology / Q000628:therapy*; D050177:Overweight / Q000000981:diagnostic imaging / Q000208:ethnology / Q000628:therapy*; D012727:Sex Characteristics; D014481:United States; D014739:Victoria; D015431:Weight Loss / Q000208:ethnology; D044465:White People; D051598:Whole Body Imaging
keywords: body composition; fat; observational study; treatment guidelines