No problem per my 2 kids' experience and consultation from doctors. This means your baby digest and absorb all your brest milk and no residue.
My 1st baby didn't poo poo for 10 days and my 2nd baby didn't poo poo for 6 days the longest. I am still brest-feeding my boy who is 8.5 months old weighted 20 pounds (2 weeks ago).