This is an example of "never say never or always" about anything.  My
first child had one huge stool (what Marianne Neifert calls a "mudslide")
every three days from day one (after the meconium).  During that time, she
gained 2 lbs. in the first month, so was obviously getting plenty to eat.
  Yes, inadequate stooling is definitely a big red flag, but if everything
else looks good, infrequent stooling, even in the newborn period, is not
always a problem.    Miriam