The thermic effect of food in underweight patients with emphysematous chronic obstructive pulmonary disease

Malnutrition and weight loss commonly occur in patients with the emphysematous type of chronic obstructive pulmonary disease (COPD), despite normal energy intakes. The present study was designed to assess energy expenditure, basal metabolic rate (BMR) and diet-induced thermogenesis (DIT) in ten patients with COPD, together with the oxidation rates of carbohydrate, protein and fat. The BMR was elevated when tested against the Harris-Benedict equation (p less than 0.001) or when compared with six age- and sex-matched controls (11.11 +/- 2.52 vs 8.12 +/- 1.31 kJ.h-1.kg muscle-1, p less than 0.05). The main difference in fuel oxidation rate was an elevated fasting fat oxidation rate in the patients compared with controls (8.31 +/- 3.09 vs 4.76 +/- 2.53 kJ.h-1.kg muscle-1, p less than 0.05). The overall thermic response to food (41.2 kJ.kg-1 liquid meal) as a percentage of energy intake was greater in the patients (49.5 +/- 6.3 vs 39.8 +/- 2.9%, p less than 0.01). The patients also displayed a greater post-prandial rate of protein oxidation as a percentage of protein intake than controls (56.9 +/- 18.5 vs 34.1 +/- 6.5%, p less than 0.05). These data suggest an increased energy cost of feeding and fasting in patients with the emphysematous type of COPD.