We’ve all seen the slow drip of companies away from the Food Marketing Institute Show in recent years, and it’s become easy to view the two emergent replacement gatherings of the food and beverage industry as polar opposites. In one corner, you have the place to be seen for good-for-you foods and beverages, Natural Products Expo West – “good for you, good for business, good for everyone,” as its slogan had it this year. In the other corner is the show for bad-for-you items (well, Pepsi, for one, prefers to say they’re “fun for you”), the National Association of Convenience Stores show. Expo West products are all-natural, sometimes organic and generally not tainted by taboo ingredients, like high-fructose corn syrup, that render them unworthy of retailers like Whole Foods. By contrast, NACS products generally taste better to the “average American” and most likely sell in numbers that are an order of magnitude greater.

Given these Manichean opposites, it was fascinating to attend the keynote speech by Michael Pollan at this year’s Expo West, in Anaheim, Calif., in March. Pollan, of course, is the best-selling author of such influential books as The Botany of Desire and The Omnivore’s Dilemma. With his excoriation of the industrial food business, Pollan has been regarded by many in the natural foods sector as a crucial ally. In many ways, he is. But as the natural foods business has scaled up, and as industrial players have bought their way in, Pollan has been hard at work warning consumers to be skeptical about the claims aimed their way by natural foods purveyors. After reading Pollan’s description, in Omnivore, of how industrial producers define “free range” (a strip of grass separated from an industrial barn by a tiny door that the enclosed livestock almost never traverse), my wife and I stopped paying a premium for free-range chicken.

Chalk up those activities, maybe, to unscrupulous food processors gaming the system. But Pollan’s critique poses a challenge to natural food purveyors in a far more fundamental way, and that was the gist of his speech at Expo West. If in some ways it was accusatory, his mild tone and subtle sense of humor insured it was only gently accusatory. But it had to be disquieting to many in the audience who are used to feeling pretty good about themselves and what they do for a living.

Pollan started by tracing the notion of “scientific eating” in America back to the mid-19th Century and showed how it taps into a Puritan heritage that has left us uncomfortable enjoying sensual activities, including eating. The past century and a half has seen a succession of foods and ingredients demonized, from the protein that Kellogg sought to drive out of the American colon with his newfangled breakfast cereals, to the red meat against which Sen. George McGovern inveighed, to the current ostracism of Omega-6 fatty acids as the enemy of “blessed” Omega-3 fatty acids. Good nutrients need to be promoted and evil nutrients must be purged from the food supply.

The resulting emphasis on “nutritionism” has diminished the role of food to a purely biological means of sustaining life rather than a cultural means of attaining pleasure, community, family, identity or ritual. That itself is a lot to lose, as proponents of the Slow Food movement have been tireless in explaining.

But there’s another implication. Foods reduced to the role of “carriers of nutrients” essentially become “the sum of their nutrient parts,” Pollan argued. “Since nutrients are invisible, therefore I need experts to tell me how to eat,” much as the priesthood mediates one’s relationship with the deity. People today have “lost the ability to eat without help.”

Pollan doesn’t think this emphasis on nutritionism works very well: not only does it ruin the pleasure of eating but it’s often based on weak science, since studying the effects of individual nutrients in isolation overlooks food’s identity as an extremely complex system.

Further, all the talk about nutrients gives an enormous edge to those selling processed foods, since they can rejigger foods to suit the latest findings – or fads – disseminated by experts. Today that’s reflected in the endless references – in store signage, product packaging and advertising – to such nutrients du jour as antioxidants and resveratrol. “Walk in the supermarket and you’re besieged by biochemistry,” Pollan observed.

Or – though Pollan didn’t say it directly – walk the aisles of Expo West, just a couple of floors below.

So, are Expo West exhibitors still the good guys? To the extent that they foster nutritionism, maybe they’re not. Pollan’s new book, In Defense of Food, aims to swap the complexity of nutritionism for the mantra: “Eat food, not too much, mostly plants.” He brought a similar message to his Expo West audience. “Don’t buy foods that make health claims,” he advised. “The healthiest food in the store is silent.” Delivered at the Produce Show, that message doubtless would be universally applauded. At Expo West it was a clear rebuke to the marketing strategies revealed on the show floor downstairs. Pollan still managed to draw an ovation from his audience. But it’s clear that those who like to revel in being at the “good for you” end of the food and beverage spectrum have some hard thinking to do about where their strategies are taking them and their customers.