Siamese throwing up

We have a 3 year old Seal Point Siamese.

She eats and then throws up, it is just like it was before she ate, except, it has enlarged

as it encounters the water in her stomach.

We tried different foods, First it was Nitro Adult, small bits of food,

we thought it might be the size and she was not eating them just

swallowing whole, then we switched to Royal Canin Siamese

large the size of Cheerios, same problem.

We have never seen a cat drink so much water, she weighs a 

healthy 8 # 6 oz, get a physical every year.

We also put the golf ball in her food dish.

HELP!!!!

Switch her to wet food. Kibble is hard to digest and throwing up right after indicates she's having some reaction to it. How old is she? Kibble is also really dehydrating, which is also why she's drinking so much water. 

Good wet foods to try.

Merrick LID, Soulistic, Weruva, Tikicat, Ziwipeak, Feline Naturals. 

On the lower end -

Fancy Feast classic only (chicken or turkey).