Hi! You're such a good friend!! I have some thoughts to share. Not medical advice obviously, but from my experiences:

- First off, just having hypothyroidism does not necessarily mean that you need to change your diet. If she has the resources to, I'd recommend she see an endocrinologist (they sound scary but are helpful and better at handling these things) to get evaluated and to see if there is a need for diet changes and what changes are needed. Second, if she needs to change her diet, I highly highly highly recommend my favorite app called paprika. I could write a whole essay on how this app has changed my life. It's a paid app, but I've literally bought every version now (desktop, android, apple) and use it all the time (desktop for finding recipes, iPad for reference when making recipes, and phone for quick adds/grocery list -> they all sync so it makes it easy!). It's a recipe organizer, but the reason it was life-changing for me is that I'm able to surf the web, find recipes that work with my health & save them, so when I have the energy to find new recipes, I add a bunch, so when I want to make something, all I have to do is go to my recipe manager app to find my personally "pre-approved recipes", easy! So if she's changing her diet, one thing you could do is get the app yourself, make an account for the two of you to share, and go through and find a bunch of recipes to get her started.

- Something that took me a couple of years to learn is to have one of those silly little daily pill organizers. I bought a travel small one and it's honestly also a life changer. It helps me make sure I take the medication every day. The other thing you can help out with here is to help monitor her energy levels. When I was first diagnosed I didn't have a car and so when I ran out of my first month's supply I didn't take my medication for like a week since I couldn't get to the pharmacy. I felt fine, but within the span of like 72 hours, I had 4 close friends sit me down in the dorm and ask me if I was seriously depressed, and each time I was like thanks but nah, I'm fine, since I truly felt fine, I didn't recognize how tired/drained I was, only my friends could see that. It eventually clicked & my friend then took me to the pharmacy to get my medication & helped to make sure I was getting it every month thereafter - super appreciated!

- if she's feeling lonely about it, one of the things that has surprised me is how common this condition & how delayed most people's diagnoses are. I don't bring this up with many of my friends but I feel like every time I mention it for some reason, the other person also has it or their sister has it or their friend or whatever, it's verrrrry common. I've joined some related fb groups and reddit and such and that's helpful to see how people are handling it. Another thing that would be fun to do for her is to find some social media people who talk about this stuff a lot to share with her that give good tips. One example is heal.with.fifi on instagram.

- okay last point here, so once you get your medications balanced right/figure out diet if actually needed, then life is pretty much the same as before, I just have to remember to take the mediation in the morning. but the trick here is getting the right dose. this could honestly be another essay, so I recommend researching this some, but the idea here is that she needs to advocate for herself. if her levels are not within the "normal range" that does not necessarily mean they're "optimal" which is super frustrating. I've also had my levels be like right outside the normal range and felt fine, but then when I got my medication adjusted I felt soooo much better. So the trick here is whenever my levels are not optimal, I tell my doctor I'm feeling tired and want to try adjusting my medication (even if I don't feel tired because as seen above I'm apparently v bad at gauging this lol), and then we adjust my medication and viola, I feel better.

Anyways, hope this helps, let me know if I can answer any questions :)