Fwiw, I had labs done 10 days ago. Kidney values were normal. My piss is always foamy but I eat 100g of protein upon waking and probably around 300g a day (more on training days).
Cheat days I skip the 100g in the morning like today and eat what I want all day. Just ate a large pizza and bag of pizzaria flavored combos. About zero foam in piss today. Only thing that changed was the amount of protein.
Foamy urine means nothing by itself. If you have the kind of bubbles soap like dawn can make in your piss, you have more cause for concern. Im just citing some personal experience with whats already been stated in this thread.