I don't know about that...babies need breastmilk or formula for the 1st year. The longest I could do it was 6 months. The biggest issue I ran into was dehydration and then having to constantly eat when I had no time to. Growing babies need more and more calories everyday. I honestly didn't have the time to take care of my kids, eat like a horse and take care of my house. I was losing weight when I had none to lose. So yeah even women who want to do it can fail at it at some point. And don't get me started on being a very shy person at the grocery store when the baby wants some boob.