Effects of Weight Loss on Body Composition and Pulmonary Function

Abstract

Background: The relationship between obesity, impaired respiratory function and weight loss is established. Objective: Some aspects need further elucidation: the different impact of the pathological modifications of body compartments (total and regional fat mass and lean body mass) on respiratory function, the choice of a restricted diet, the relationship between the modifications 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, respiratory function was assessed by spirometry; body composition was assessed by dual-energy X-ray absorptiometry, allowing the direct estimation of total and segmental body fat and lean body mass. Results: Weight loss was sustained 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 parameters, and was unmodified after weight loss. Conclusions: Mediterranean-style restricted diet was well accepted and enabled a selective decrease in fat mass, with a good improvement in lung function. Truncal fat (as well as abdominal fat) was decreased, while truncal lean body mass (i.e. respiratory muscles) were not affected, as expected in obese subjects with respiration problems.

The effect of adiposity measured by dual-energy X-ray absorptiometry on lung function

“…Using low-level radiation, DXA is able to quantify fat and lean tissue more reliably than estimations of body fat based on skin-fold thickness. To date, DXA has been used to demonstrate an association between total body fat and respiratory function parameters in groups of elderly males [6], children [13] and obese subjects undergoing weight loss through a calorie-restricted diet [14].…”

Pre- & post- bronchodilator pulmonary function test in Indian females: a survey in and around Jaipur

“…[24][25][26] On average, urban population was a bit older, but even if the little age difference was compensated at the rate of 20ml/ year, PFT parameters were still lower in the urban females than their rural counterpart.…”

Obesity and the Respiratory System: New Methods to Examine anOld Question

“…In this issue of Respiration De Lorenzo et al [4]propose the technique of dual-energy-X-ray absorptiometry (DXA) as a tool to study body composition and fat distribution in man. They document in 16 obese subjects (none apparently with cardiopulmonary failure) both a positive correlation between lean body mass and lung volumes and a decrease in fat mass accompanying weight loss.…”

“…After all, the former ratio would serve as an index of the rotund body shape we empirically associate with OHV. How do DXA measurements compare as predictors of lung volume with simple measures of circumference and height which were also presented in the paper of de Lorenzo et al [4]? Finally, would observations made with the DXA technique correspond to any genetic markers of obesity [5].…”

“…De Lorenzo et al [4]have put forth a bold challenge to the pulmonary community to enhance our understanding of the relationship between obesity and cardiopulmonary dysfunction.…”