Whereas all the studies in the literature examining the optimal timing of the prandial bolus uniformly demonstrated that delivering a bolus 15-20 min before eating rather than immediately before or after the meal significantly improves postprandial glycemia,studies examining the optimal bolus type required to cover higher-fat meals showed discrepant results.
Four studies reported that the combo wave bolus was the most effective method, Whereas one suggested that the standard bolus with insulin delivered 15 min before the meal was superior and another reported no differences in glucose excursions among normal, combo wave, and extended boluses after pasta meals.
Methodological differences and issues confound the evaluation of the published literature.
The duration and split of the bolus types varied across studies.
Furthermore, failure to optimize basal rates as part of the study protocol could have affected the findings of some studies.
In addition, differences in the GI and macronutrient content of the test meals and duration and split of the bolus types in the studies may have contributed to the differences in the results.
Of note, some studies had a relatively short postprandial monitoring period and, thus, may not have detected the delayed hyperglycemia from dietary fat.