You probably wouldn't wanna listen to a newb in the business of eating right and lifting weights like myself, but here it goes nonetheless...
At this point in time, there is not enough data to tell whether it's detrimental or not. You can tell by the ambivalence of the doc's replies in the post I linked to previously and the following one.
It's not that he's answering the question, but as a scientist, he carefully avoids being too assertive on things that haven't been studied in deep.
At the end of the day, and in such still-obscure-areas, you should go by the experience of other people. Nobody ever complained from taking extra BCAAs through supps. In fact, it's the opposite. BCAAs are praised by athletes around the globe. Heck, there was a "spot the fake" article a few months ago about the potential of BCAAs to make you drag your ass to the gym. In short, I'd say that any detriment of the insulin spikes is outweighed by the edge amino acids supplementation give you.