How do vegetables
differ in nutrition?

The full narration of the video.

Cucumber and spinach are both vegetables. So what's the difference? At the market, it feels like any pound of vegetables covers the day. But vegetables differ far more than you'd think.

Picture vegetables as a row of little shops. Every shop has stock, but each one specializes. Start with the dark green shop. Spinach, bok choy, broccoli: the darker the leaf, the fuller the shelves. Gram for gram, spinach has over twenty times the folate of cucumber.

For the vitamin that helps a cut stop bleeding, the gap is even bigger. Next door is the orange and red shop: carrots, pumpkin, tomatoes. Their signature product is beta-carotene. Inside the body, it becomes a vitamin that guards your eyes, helping you see in dim light.

A hundred grams of carrot covers about a day's worth for an adult. Further on is the bean shop. A hundred grams of edamame has around ten grams of protein, rare for a vegetable. One shop isn't really a vegetable shop at all. It's a grain store: potatoes, yams, taro.

They mostly sell starch. China's dietary guidelines count them as staple food. Have a plate of shredded potato, and take a little less rice. Last is the pale shop: cucumber, winter melon, lettuce. A cucumber is ninety-five percent water. Crisp, refreshing, low in calories, but not much else on the shelf.

Shop at only one, and your basket is always missing something. Nutritionists call the first two shops dark-colored vegetables: deep green, red, orange and purple. China's guidelines suggest 300 to 500 grams of vegetables a day, with more than half of them dark-colored.

Buying it is one thing. Getting it home is another. Beta-carotene dissolves in fat, which helps the body absorb it. Carrots stir-fried in a little oil beat carrots boiled in water. Vitamin C in leafy greens leaks into water; long boiling can lose half of it. A quick stir-fry with little water keeps the most.

So color works like a ready-made shopping list. The more colors on the plate, the more complete the basket. Before dinner tonight, count the colors of vegetables on the table. Come back and tell us: how many did your table get?