Then it was off to meet Dr Win - Win Paris, PhD, a tiny, mop-topped geriatric in an Evel Knievel jacket, who claims to have earned "millions and millions and millions and millions and millions and millions of dollars" from fitness machines. Within a few minutes of their first meeting, Dr Win had Theroux stripped to the waist to try out a sit-up machine, and shortly afterwards he was bent over the Beautiful Buns machine, straining while Theroux whacked his buttocks. "Like wood," Theroux admitted, and kept on whacking. "This is awesome!" Dr Win cried out. "Harder!"
At their next meeting, Dr Win wrestled Theroux to the floor by way of greeting - over-exuberance excused by anxiety in the run-up to the television launch of his Global Fitness Revolution. (This turned out to be on a local cable station where they reckoned an audience of 10 was pretty good.) The third time around, Dr Win opened the door of his apartment wearing nothing but a bathrobe. I was becoming seriously worried about the direction this relationship was taking.
Meanwhile, Theroux had travelled west to California to meet Cesare, a cosmetics expert who was about to launch into the world of infomercials with his face-shaping make-up. To demonstrate its effectiveness, he treated Theroux to a make-over, including haircut: Theroux stared at his own reflection. "Wow! That's amazing! The hair has so much body!"
This is what makes Theroux such an effective commentator on America: he never succumbs to the temptation to giggle, offering instead a perfect imitation of American enthusiasm - he seems to enjoy the perpetual rapture of a small boy in front of a really good Scalextric set-up. Watching last night, it seemed genuine, as though he really had given in to the sheer abundance of American life. Preparing to try his own hand at an infomercial, he rhapsodised over the goods on offer - a smoke odour absorber: "It actually absorbs the odour of the smoke," he gasped.
When he finally went on air, though, touting a domestic paper-shredder, it became clear this was an illusion. While the studio crew screamed directions in his ear-piece ("Start shredding! Shred while you talk! Five pieces at once! Convenience!"), he turned awkward, shy, ironic: British, in fact. It was a sad moment: Theroux looks as if he really loves America, wants to be a part of it. In the end, though, faced with its plenty, he froze - a small boy with his nose pressed against the window. But that's why you can trust him.
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