Bland-Altman plots. The dashed line represents the mean difference (on graph A, the difference = 0) and the dotted lines represent the 95% limits of agreement. A: comparison of measured and estimated GL values for 0, 5, 10 and 20 g carbohydrate from white bread and glucose and 4 low-carbohydrate foods. Measured values were calculated from the regressions of AUC on dose of glucose ingested for each subject; estimated values were derived from EGL. B: comparison GL values estimated from EGL for 3, 5, 10 and 20 g oral glucose and the amount of glucose fed. GL was estimated from EGL using equation (11) (see text) as follows: GL = 0.78 × EGL - 0.2.