I was up and down 3 times through my 20s, much larger swing from tops to bottoms than you and I have kept it off for 6 going on 7 years now. Again others I know who did similar were all health scares who internalised that being way over weight was going to cut years off their lives, successfully keeping weight off means behavioural changes not just crash dieting or exercise sprints now and then.

Wouldn’t look to the likes of Kissinger - those people have access to things you and I do not have. Not just the best doctors money can buy, but you think he’s going on a waiting list if he needs a new kidney? I doubt it..

NZ life expectancy may not have dropped but excess deaths have increased post Covid (AUS & NZ were the only two countries that had a positive correlation between lockdowns and death rates to my own chagrin - every other country showed negative correlations). They also don’t have the obesity rates of the US - sure the Māoris are fatties but they’re not meaningfully shifting national level stats whereas in the US it’s all major demographics that have seen obesity skyrocket in the past 30 years, far ahead of other nations who are all getting fatter but at slower rates.

We’re never going to get answers from “public health” about any of this given how ideological and captured they are and as your health is directly tied to your life and no-one else’s, it’s incumbent on individuals to make changes rather than wait for approved scientists who are captured and provably full of shit to come up with things.