What’s the best way for someone who’s struggled with their weight to start turning things around?

My friend uses Weight Watchers, which seems to have an integrated lifestyle management app and IRL meets, etc.

I knew two people who got stomach stapling, and I think they got at least temporary relief.

Nassty, morbid obesity may need a specialist / immediate action.

Weight drifting slowly higher might be addressed with reduced stress, more exercize, or other lifestyle changes.