I can tell you about the moment it changed. It was just after the chief tribune finished a call from the president of France. He stood up from behind the desk he’d taken from the last president and slapped his belly.

I expected him to follow the slap by saying, ‘need to something about that,’ as he did on most days. He’d meant it when he was a young man but by then, it was more of a tic that I hardly noticed.

Instead, he asked me, “what’s the national obesity rat...