Is there some information out there that addresses nursing mothers milk supply when working out heavy?
It is not so much her milk supply she needs to worry about- the breast milk is on a supply and demand basis. However, if she is not getting enough or correct food her body will turn inward to take what it needs- so thus, depleat her from her own health. If you think about it, women all over this world in poverty and starving- take Africa for example, still make milk to feed their babies even when they are lacking food- but to make sure she is healthy she need to be eatting correct and also having an active life. I would say start lifting slow, and work her way up- just because like the PP said, you do not want her tired- and nursing takes a lot out of a mom- I know, been doing it for 4 years. If the breastmilk taste funny- she will know, your baby will show her signs. Just do what feels right, eat good and watch your babies signs.