This is what my local LLL leader told me when I first had Béla. She's only 8 weeks but another thread here provoked the thought again.
She said that babies stop pooping (around 6 months, I'm assuming) when the types of colon bacteria has changed, to the kind that absorbs/digests solids. Meaning that just BM won't produce any poo. She said that if anyone tells me that I am wrong about this, NOT TO LISTEN, because she really, really knows what she's talking about. Said her daughter went 12 days, and the longest she's heard of was 2 weeks! Said it's the weirdest thing but true. Insights?