Multiple previous studies5–9 have attempted to answer that question through either population-based or cohort studies. A large population-based study9 utilized the data of 11,277 participants in the European Community Respiratory Health Survey (ECRHS). It demonstrated a rise in AHP with the increase in BMI in men (ECRHS slope decrease, 0.027 for each unit increase in BMI; 95% confidence interval, −0.044 to −0.010; p = 0.002),8 but not in women (ECRHS slope decrease, 0.014; 95% confidence interval, −0.033 to 0.005; p = 0.41). However, the study was not designed to allow for the follow-up of a possible variation in AHP with changes in BMI. In a more recent study from Finland, Stenius-Aarniala et al7 evaluated the effect of 14 weeks of controlled dieting on obese asthmatic patients. At the end of the dieting, there was a statistically significant increase in both FEV1 (p = 0.009) and FVC (p = <0.001), but not in the peak expiratory flow (p = 0.06) of the study group compared to the control group. Even after one year, the differences in FEV1 and FVC remained statistically significant (p = 0.02 and 0.001 respectively). However, the study had no account of group airway responsiveness to methacholine challenge either prior to or after the dieting period.