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Weight loss composition is one‐fourth fat‐free mass: a critical review and critique of this widely cited rule
Author(s) -
Heymsfield S. B.,
Gonzalez M. C. C.,
Shen W.,
Redman L.,
Thomas D.
Publication year - 2014
Publication title -
obesity reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.845
H-Index - 162
eISSN - 1467-789X
pISSN - 1467-7881
DOI - 10.1111/obr.12143
Subject(s) - dieting , weight loss , lean body mass , fat free mass , fat mass , obesity , lean tissue , low calorie diet , medicine , endocrinology , adipose tissue , gerontology , psychology , body weight
Summary Maximizing fat loss while preserving lean tissue mass and function is a central goal of modern obesity treatments. A widely cited rule guiding expected loss of lean tissue as fat‐free mass ( FFM ) states that approximately one‐fourth of weight loss will be FFM (i.e. Δ FFM /Δ W eight = ∼0.25), with the remaining three‐fourths being fat mass. This review examines the dynamic relationships between FFM , fat mass and weight changes that follow induction of negative energy balance with hypocaloric dieting and/or exercise. Historical developments in the field are traced with the ‘ Q uarter FFM R ule’ used as a framework to examine evolving concepts on obesity tissue, excess weight and what is often cited as ‘ F orbes' R ule’. Temporal effects in the fractional contribution of FFM to changes in body weight are examined as are lean tissue moderating effects such as ageing, inactivity and exercise that frequently accompany structured low‐calorie diet weight loss protocols. Losses of lean tissue with dieting typically tend to be small, raising questions about study design, power and applied measurement method reliability. Our review elicits important questions related to the fractional loss of lean tissues with dieting and provides a foundation for future research on this topic.