Fasting respiratory quotient as a predictor of long-term weight changes in non-obese women

Background/Aims: The identification of metabolic and environmental predictors of excess body fat is still far from being achieved. The aim of this study was to evaluate whether respiratory quotient in non-obese women is a predictor of body weight changes after a 6-year follow-up period. Methods: Forty-three non-obese healthy women participated in the study. Their baseline general characteristics were: age 40.5 +/- 12.8 years; height 159 +/- 7 cm; weight 61.8 +/- 10.1 kg, and body mass index (BMI) 24.4 +/- 3.8 kg/m(2). At baseline basal metabolic rate and respiratory quotient were determined by indirect calorimetry, while weight and BMI were recorded at the first observation and after the 3- and 6-year follow-ups. Results: At the first observation basal metabolic rate was 5,360 +/- 713 kJ/day and respiratory quotient 0.850 +/- 0.052. After 6 years, with weight changes equal to 1.4 +/- 4.5 kg, baseline respiratory quotient was a significant predictor (p < 0.05) of changes in body weight or BMI together with baseline BMI. Conclusions: This follow-up study confirms that a high respiratory quotient (measured on free diet) predisposes to weight gain, especially in women with the highest baseline respiratory quotient (above the 90th percentile of the distribution for this variable). Copyright (C) 2004 S. Karger AG, Basel.