Effects of weight loss on body composition and pulmonary function

Background: The relationship between obesity, impaired respiratory function and weight loss is established, Objective: Some aspects need further eluci dation: the different impact of the pathological modifications of body comp artments (total and regional fat mass and lean body mass) on respiratory fu nction, the choice of a restricted diet, the relationship between the modif ications of body compartments and the variations in respiratory parameters after weight loss. Methods: The restricted diet was elaborated according to the traditional Mediterranean diet. In a series of 16 obese patients, resp iratory function was assessed by spirometry; body composition was assessed by dual-energy X-ray absorptiometry, allowing the direct estimation of tota l and seg mental body fat and lean body mass. Results: Weight loss was sust ained mainly by fat mass decrease, mostly upper body fat. Total and truncal lean body mass were not affected. Lung volumes and function were improved. A correlation was observed between lean body mass and respiratory paramete rs, and was unmodified after weight loss. Conclusions: Mediterranean-style restricted diet was well accepted and enabled a selective decrease in fat m ass, with a good improvement in lung function. Truncal fat (as well as abdo minal fat) was decreased, while truncal lean body mass (i.e. respiratory mu scles) were not affected, as expected in obese subjects with respiration pr oblems.