Manhattan’s wiry and willowy were eager on Wednesday to dissect how they brought home such an honor. First and foremost, they said, Manhattan is a place where people walk. Even subway riders need to climb stairs. Storefront yoga studios, parks and pedestrian-friendly streets make working out relatively easy. Beyond that, Manhattan is the national capital of disparate subcultures of the skinny: Aspiring models. Nightclubbing hipsters. Gay men with the time and money to chisel their physiques at the gym. Park Avenue society matrons who remain preternaturally slender into their 70s, the “social X-rays” satirized by Tom Wolfe.