I started primal when my baby was 10 months. She was still demand feeding a lot then. I've never worried about counting calories. I just eat primally and the weight it coming off. I probably consume the same amount of calories but the type differs a lot. The only time my supply was affected was when my calories dropped too low. She is 15 months now and still nurses a decent amount, she also follows a primal diet.
My advice is just eat primal foods when you're hungry and don't expect too much while feeding. Your body will naturally want to hang on to a bit more.
Became Primal August 2011
SW - 84kg / 185lb
CW - 60kg / 132lb
GW - 60kg / 132lb