As I said, I am not really an expert, so I hope that bf experts here will help you better. But what I was told when I was bf my DS was that if bf sessions were too frequent for his age and he wasn't able to take a full feed at every session, he would have lost the most fat part of the milk, that comes after the light and sweet initial bm. So, encouraging snacking would have had the opposite effect of decreasing the total amount of calories he could get. Just to put this on the table as a possibility...