fat content of the mother's milk is the LEAST LIKELY reason for this baby's
failure to gain weight.  try instead:

not frequent enough nursing (at least once an hour during the day, less
often at night)

stay on one breast for several feedings to make sure hind milk is being
transferred

check baby's suck and swallow, check his palate, watch him nurse

do before and after weighing to see if baby is getting anything

ask mom about supply, letdown, dripping, did her breasts change during
pregnancy and since delivery

ask mom about postpartum bleeding -- she may have no milk b/c of retained
placental fragments

check baby's heart -- he may be getting plenty of milk for a normal baby,
but not enough for a baby with a heart defect

final thought -- FEED THE BABY -- while you figure out what the problem is.

Kathy Dettwyler, off to a conference