What steps to show that certain drinks could be medically necessary for check on luggage?

I'm planning a trip to Brazil to get all on six dental implants because I don't have any teeth. Unfortunately, this also means that it's impossible for me to eat any real food or snacks airlines offer until I have teeth.

I ended up in the ER because of starvation ketoacidosis. I was kept there for two weeks and thankfully found some drinks (protein shakes) and some minced food that helped me get discharged after all of my levels returned to normal. Was also treated with PPN injections for my entire stay.

My main concern is with how long the flights/layovers could be is that I will definitely need some source of protein during the flights.

I know there's a slight possibility that airlines could allow me to check the fluids but that they would need to take additional security steps or something like that, and I'm perfectly willing to get a doctor's note that says it's medically necessary for me to have these drinks. I also know that I'll need to declare any food or drink in advance, but was wondering how I can prove that I'll need them or if it's even a possibility for me to do what I'm writing.

I'm just wondering what other steps I need to take to make it as smooth as possible for myself/insurance/security/airlines because this is a huge trip for me and really the only chance that I have at getting my teeth back and just want to make sure there won't be any further health complications while I'm either flying or in a foreign country.

Thanks in advance.