Well, don't say you weren't warned when it turns out the miracle is not such a miracle after all and it all massively backfires in a few decades, at which point you're still going to have to actually fix the real underlying causes.
The class of drugs having a 2+ decade negative health effect greater than the negative health effect of obesity over the same period, without any obvious short-to-medium health effect, is likely to be small.
For obese people: probably. The overall health benefits for overweight people are a lot less clear. Being merely overweight (rather than obese) is not that strongly associated with negative health effects.
Look, I hope you're right. If in 20 years time we look back at these comments and no negative effects have manifested then I'll happily buy you a beer to celebrate. Hell, I'll buy you an entire crate of beer. But I think this is one hell of a risk to take.