To be fair, none of the nutrition tracking apps are good. That's why they cost so much, they're capitalising on a trend. None of them are actually good.

Avoid sugar and control portion sizes, that'll get you most of the way there.

I track hydration with WaterMinder and I track my meds with Apple Health — that's about it. I did pay for WaterMinder (note: Apple Health does it for free and shortcuts make it just as easy, I just wanted to be fancy about it).

Garmin's whole UI/UX is awful, I just use it for the data.

Also it's totally impossible to tell which machine in the gym the watch is paired to