S.H.
WHOLE milk is important up until at least 2 years old...the reason is they need the milk "fat" in it for brain development. They should not be "dieting" at this age. It is for nutrition.
This is what I did with my son: mix her regular formula as usual....fill the bottle about half way. Then add milk to it. Gradually, add more and more milk, thereby lessening the formula proportions. This is what I did with my son, as he did not like the "taste" of milk. Now, he is fine with milk.
She could be having the diarrhea because now, the milk is "richer" than she is used to.
Good luck,
~Susan
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