I agree entirely that tight control is vitally important.but do not feel that Dr Bernsteins methods are necessary or good advice to most people, in particular most type 1s.
The DCCT (as included as part of the data set discussed above) has also recently produced a report on the diet of those characterised with good control..... ie those that had fewer complications.
Association of diet with glycated hemoglobin during intensive treatment of type 1 diabetes in the Diabetes Control and Complications Trial
http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=19106241
Conclusion
In summary, this analysis of DCCT participants who were randomly assigned to intensive therapy found that diets higher in fat and saturated fat and lower in carbohydrate were associated with worse glycemic control, independently of exercise, triglyceride concentration, and BMI but not after the baseline degree of glycemic control or insulin dose were controlled for. Contrary to commonly reported dietary practices of persons with diabetes who may restrict carbohydrate intake, these results support current recommendations regarding the limitation of saturated fat intake while promoting the consumption of nutrient-dense carbohydrates, such as fruit, whole grains, and vegetables, with appropriate insulin doses as needed. Future research needs to explore whether persons with diabetes inadvertently increase their saturated fat intake in their efforts to control carbohydrate intake and glycemia
It is worth reading the discussion section because as in all types of research like this there are some confounding variables. When iresearchers adjusted to take into account Hb A1c before the trial, the results were not significant.... They discuss the possible reasons for this ( better existing management skills at baseline, or possesing some residual insulin for example). It is perhaps possible that people who had higher levels at baseline are those (that for whatever reason) find control more difficult and may indeed cut their carbs and substitute with fat in their efforts to achieve control.
The researchers also suggest that carbohydrate content of the diet was less critical than the sat and monounsaturated fat content and discuss this.