Thirteen patients with stable airway disease were fed a diet high in carbohydrates, and 35 minutes later metabolic and ventilatory effects were observed. The six patients who did not retain carbon dioxide increased their mean respiratory quotient from 0.86 +/- 0.07 to 1.03 +/- 0.04, their mean minute ventilation from 10.3 +/- 3.0 to 12.8 +/- 4.0 L/min, mean carbon dioxide production from 0.23 +/- 0.04 to 0.29 +/- 0.02 L/min, and mean oxygen consumption from 0.27 +/- 0.07 to 0.29 +/- 0.03 L/min (all P less than 0.05). The arterial carbon dioxide tension (PaCO2) did not change significantly from baseline values. The seven patients who retained carbon dioxide responded similarly, except that their mean arterial oxygen pressure (PaO2) increased significantly from 50.9 +/- 4.4 to 57.7 +/- 5.5 torr (P less than 0.05). In addition, the mean PaCO2 increased from 54.5 +/- 6.4 to 54.9 +/- 6.4 torr (not significant). We conclude that the increased endogenous carbon dioxide load resulting from a meal high in carbohydrates is well tolerated by most patients with chronic airway disease.