As the world population grows, we have a pressing need to eat better and farm better, and those of us trying to figure out how to do those things have pointed at lots of different foods as problematic. Almonds, for their water use. Corn, for the monoculture. Beef, for its greenhouse gases. In each of those cases, there's some truth in the finger-pointing, but none of them is a clear-cut villain.
There's one food, though, that has almost nothing going for it. It occupies precious crop acreage, requires fossil fuels to be shipped, refrigerated, around the world, and adds nothing but crunch to the plate. It's salad, and here are three main reasons why we need to rethink it.
1. Salad vegetables are pitifully low in nutrition.
Organic consultant Charles Benbrook and his colleague Donald Davis have developed a nutrient quality index — a way to rate foods based on how much of 27 nutrients they contain per 100 calories. Four of the five lowest-ranking foods (by serving size) are salad ingredients: cucumbers, radishes, lettuce and celery. (The fifth is eggplant.)
Those foods' nutritional profile can be partly explained by one simple fact: They're almost all water. Although water figures prominently in just about every vegetable (the sweet potato, one of the least watery, is 77 percent), those four salad vegetables top the list at 95 to 97 percent water. A head of iceberg lettuce has the same water content as a bottle of Evian (1-liter size: 96 percent water, 4 percent bottle) and is only marginally more nutritious.
Collard greens are 90 percent water, which still sounds like a lot. But it means that, compared with lettuce, every pound of collard greens contains about twice as much stuff that isn't water, which, of course, is where the nutrition lives.
The corollary to the nutrition problem is the expense problem. The makings of a green salad cost about $3 at my supermarket. For that, I could buy more than two pounds of broccoli, sweet potatoes or just about any frozen vegetable going, any of which would make for a much more nutritious side dish to my roast chicken.
When we switch to vegetables that are twice as nutritious — like those collards or tomatoes or green beans — not only do we free up half the acres now growing lettuce, we cut back on the fossil fuels and other resources needed for transport and storage.
2. Save the planet, skip the salad.
Lots of what passes for salad in restaurants is just the same as the rest of the calorie-dense diabolically palatable food that's making us fat, but with a few lettuce leaves tossed in. Next time you order a salad, engage in a little thought experiment: Picture the salad without the lettuce, cucumber and radish, which are nutritionally and calorically irrelevant. Is it a little pile of croutons and cheese, with a few carrot shavings and lots of ranch dressing?
Call something "salad," and it immediately acquires what Pierre Chandon calls a "health halo." Chandon, professor of marketing at Insead, an international business school in France, says that once people have the idea it's good for them, they stop paying attention "to its actual nutritional content or, even worse, to its portion size."
Items labeled "salad" at chain restaurants are often as bad, if not worse, than pastas or sandwiches or burgers when it comes to calories. Take Applebee's, where the Oriental Chicken Salad clocks in at 1,400 calories. Even the Grilled Chicken Caesar, the least calorific of the salads on the regular menu, is 800 calories.
I asked Bret Thorn, columnist at Nation's Restaurant News, about salads. "Chefs are cognizant of what's going on in the psychology of diners," he said. "They're doing a kind of psychological health washing," not just with salads, but with labels like "fresh" and "natural," and foods that are "local" and "seasonal." "A chef is not a nutritionist, or public health advocate," Thorn points out. "They make food that customers want to buy."
3. Salad has unfortunate repercussions in our food supply.
Lettuce has a couple of No. 1 unenviable rankings in the food world. For starters, it's the top source of food waste, vegetable division, becoming more than 1 billion pounds of uneaten salad every year. But it's also the chief culprit for foodborne illnesses. According to the Centers for Disease Control, green leafies accounted for 22 percent of all food-borne illnesses from 1998-2008.
None of this is to say that salad doesn't have a role in our food supply. I like salad, and there's been many a time a big bowl of salad on the dinner table has kept me from a second helping of lasagna. And the salads we make at home aren't the same as the ones we buy in restaurants; according to the recipe app Yummly, its collection of lettuce-based salads average 398 calories per serving.
But as we look for ways to rejigger our food supply to grow crops responsibly and feed people nutritiously, maybe we should stop thinking about salad as a wholesome staple, and start thinking about it as a resource-hungry luxury.
Haspel writes about food and science for the Washington Post. She farms oysters on Cape Cod.