Preprandial blood glucose values: influence on glycemic response studies

Through regressional analyses on data from two glycemic response studies, the influence of various preprandial blood glucose (PPBG) values upon glycemic response is highlighted. Repeated calculations on different subsamples of meals where the PPBG was below a given value showed that the influence of PPBG upon net glycemic response not was linear in the whole PPBG range. It was found that a PPBG less than 13 mmol/L had no influence upon net glycemic response whereas PPBGs greater than 13 mmol/L were significantly negatively correlated to the net glycemic response. To obtain more valid glycemic index figures we recommend that participants with PPBG greater than 13 mmol/L are excluded from glycemic response studies and that the number of participants are increased substantially.