Can BDD and LEAN methodologies be used together?

I was chatting to my product manager last week and he was bemoaning the lack of progress on our product. It's a fair criticism too. So we got to talking about to describe the writing of requirements. I'm a big fan of BDD and using something like the Gherkin syntax to describe how the system should behave in terms of a user or actor.

He was pretty dismissive of BDD and said we should be using LEAN methodologies like SBCE (set based concurrent engineering) and other stuff which I don't know a massive amount about given I've not read much on LEAN practices so far.

Are these two methodologies mutually exclusive? If not BDD then there would need to be some other way of describing what the system should do. Does LEAN have its own language for requirements?