It's cheap to try
Personally I'd like fewer fatties in my neighbourhood despite the cost: they take up two seats on the bus, they walk too slowly, and they offend my eyes. I'm sure you could put a figure on the pain I suffer, in QALYs, of having to see fat people.
At the same time, quite a few of McKinsey's 77 solutions are no-cost or negligible-cost. Perhaps it's worth trying the half-dozen cheapest solutions? And what can we learn from elsewhere? The Danes banned trans-fat: how is that working out for them?