Yes the tsh is generally used as an indicator.
You doctor should run a full thyroid panel including
T4
Free T4
Tsh
Tuptake ( not done too much anymore) but it think it’s helpful to get the full picture.
T3 total
Free T3
If all the others are normal, I wouldn’t worry about the tsh.
The thyroid system is complicated with constant checks and balances.
Tsh stimulates the thyroid to make more T4.
So when it is high, it could mean your thyroid isn’t making enough T4.
But you should have it checked.
This will makes wt loss hard for sure. As for diet I’d say lose the Soy, gluten and dairy for sure. I would also make sure you don’t use fluoride it negatively effects thyroid. Perhaps speak with a naturopath. I started taking a supplement and my levels popped back up. It’s called GTA if you wanted to research it.
I was extremely depressed, couldn’t control my weight and had such low energy. Hopefully that’s not the case for you. I’m still working through it.