I went to four deep thinkers about food and asked them what they'd most like to see labeled. What's the most important thing to know about food, if you're trying to be a health-conscious, responsible consumer?

I started with Jonathan Foley, director of the Institute on the Environment at the University of Minnesota. On Twitter, Foley is @GlobalEcoGuy.

Foley was reluctant to give an answer at first; simple labels can be misleading, he said. But eventually he came up with his top three label suggestions.

"First, deforestation, yes or no?" he said. In other words, did people cut down trees to grow this food? That's been happening in Indonesia and Malaysia to make room for palm oil plantations. According to Foley, he can't think of a "bigger hammer to the environment" than deforestation.

Second, Foley continued, "How much water did it take, and from where?" Farmers around the world have been draining rivers and underground aquifers to water their crops. "And No. 3, how much fertilizer did it take, and did you manage to keep it from running off?" Fertilizer runoff from farms has choked lakes and estuaries from China to the Chesapeake Bay.

Of course, the state of our environment certainly isn't the only thing to think about with food.

"I just want to know that folks are getting paid a basic living wage," says writer Tracie McMillan. For her book, The American Way of Eating, McMillan went undercover and worked in the vegetable fields of California.

There are field workers who don't even earn a minimum wage, she says. Some workers get cheated out of their pay.

People have worried about this sort of thing with imported food, she said. It led to Fair Trade coffee and bananas, "and the presumption was, you didn't need something like that for the U.S., because we had labor laws that were enforced enough that anything in the U.S. would have been produced under [acceptable] labor conditions. And that's unfortunately no longer the case," McMillan says.

This idea was echoed by Danielle Nierenberg, co-founder of the Food Tank — Nierenberg calls it a food think tank.

She'd love to see food get a grade based on how farmworkers were treated, as well as farm animals — "something that made it clear to consumers that this was a product where we did our best to make it fairly, justly and humanely."

It's important to keep it simple, she says. If a label is complicated, people just get confused. "People are so bombarded with information, particularly around food, that they don't know what to choose, and they don't really realize the impact of what they're eating on their personal health," Nierenberg says.

This is exactly the problem that my last big thinker wants to solve. Michael Jacobson is the grand old man of food labels. He's executive director of the watchdog group Center for Science in the Public Interest.

"Twenty years ago, we led the effort to get nutrition facts labels on foods," Jacobson says. "Now they're there. Everybody loves them. But they haven't had much impact on the American diet."

So Jacobson now believes we don't need more fine print about sodium and sugar. We need something that grabs people's attention. "A label that would spur them to choose healthier foods."

Jacobson wants to put some sort of symbol, or number, right on the front of the package, that gives food a grade. You'd give food credit for all the good stuff in it, such as vitamins and minerals. You'd take away points for trans fat, salt, saturated fat, "and come up with a red dot, or the number 50, or whatever."

Jacobson says this label should just focus on whether foods are good for you. The other things — worker conditions, environmental impact — may be interesting, "but I don't think you can turn a food label into an encyclopedia," he says.

On the other hand, it is possible, with modern technology, to make labels both small and encyclopedic. Foley, the Global Eco Guy, says that his dream would be a bar code that you could scan with your smartphone to get details about everything in that package: all the ingredients, where they were grown, and how.

Even if most people didn't bother looking up that information, he says, it still would be powerful. "If companies had to think about all those details, and really disclose them more, I think you'd see some pretty dramatic shifts in how they operate."

It could affect everything that our food touches: forests, water, wages and health.

Copyright 2013 NPR.

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What's The Most Important Thing Food Labels Should Tell Us?