Just in case you’re not joking: A nursing mother’s body burns extra calories to create breast milk. From experience, the weight loss benefit is a great incentive to nurse. While there is fat in breast milk, unless the baby has very serious metabolic issue there is no chance for a child to get fat from it. In fact babies with weight issues, and yes they do exist, are formula fed. If you’re not joking, sorry!
I have seen tremendously obese babies on just breast milk. I have seen thin formula babies.