Why sm amt of CHO for bkfst?

[mrod, LPN, LVN]

My instructor mentioned that the Diabetic should have the least amt of CHO at breakfast and the most at dinner. Now I am confused on the reason why when Regular insulin is given and I think I understand for NPH.

For example: at 7am you take their CBG and it is say 300, so say the sliding scale states 4 units of Reg insulin is to be given and then they can eat their breakfast which is small amt of CHO and more protein and fats. The onset of Regular insulin is 30-60 min so why sm amt of CHO, why does it matter for Reg?? The Reg insulin is going to be working in 30 to 60 min so if there is not enough CHO for the insulin to work on, wouldn't this make them possible for hpoglycemia?? Now if this was NPH, this makes sense to me because the onset is 3-4 hrs and too much CHO will only rise the blood sugar b/c you need time for the NPH to get there.

The Reg insulin thing has me confused. Anybody can shed some light for me? Maybe I heard her wrong or something....maybe she was only stating this for NPH??

Thanks.

[RNinJune2007, RN]

Don't know if this will shed light on your question, but the fact is, with sliding scale insulin you are basically "chasing your tail." You are treating what WAS but not what will be (after they eat). Our hospital system recently did a HUGE study on the subject, and in addition to covering immediately, it is also important to cover based on the CHO's they receive for their meal.

I don't know if this makes sense to you, and I know this isn't really answering your question, BUT, it's just another factor that goes into the decision of how much insulin they get.