The importance of fat free mass maintenance in weight loss programmes.

Obese individuals have excess total body mass, a condition resulting from an overaccumulation of both fat and fat free mass (FFM). Research has been focusing on the need to maintain FFM during weight loss because of its integral role in metabolic rate regulation, preservation of skeletal integrity and maintenance of functional capacity. It has been suggested that FFM loss should compose no more than 30% of total weight loss. Because skeletal muscle in the obese has been shown to consist of an increased amount of low density muscle tissue, impaired strength: size ratio, less capillarisation, decreased mitochondrial density, and consequently impaired work capacity, it may be necessary to stratify FFM into essential and less essential FFM categories. With this categorisation, more specific quantification of FFM loss and maintenance can be made. While FFM influences several physiological functions, it may be that a minimal loss of FFM from the obese state is not only unavoidable, but actually desirable if the loss is in the form of less essential FFM.