营养专家吐槽沙拉.doc

Why salad is so overrated
As the world population grows, we have a pressing need to eat better and farm better, and thogetables 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.
Take collard greens. They 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. But you’re also likely to eat much more of them, because you cook them. A large serving of lettuce feels like a bona fide vegetable, but when you saute it (not that I’m recommending that), you’ll see that two cups of romaine cooks down to a bite or two.
The corollary to the nutrition problem is the expense problem. The makings of a green salad — say, a head of lettuce, a cucumber and a bunch of radishes — 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.
Lettuce is a vehicle to transport refrigerated water from farm to table. When we switch to vegetables that are twice as nutritious — like those collards or tomatoes or green