Salad greens are a low-calorie, nutrient-rich and tasty way to meet your daily vegetable needs. But you may wonder if one type of lettuce makes a better choice over another.

Bok choy, also known as Chinese cabbage or pak choi, is a leafy, green vegetable that is frequently used in Chinese cooking. While it is often combined with other ingredients in a stir-fry, bok choy is also delicious when steamed or boiled and served on its own as a healthy and flavorful side dish.

Raisins are a natural sweet treat, but may not be enjoyed if you have an allergic reaction after consuming the dried fruit. Raisins are made from dried grapes and are not considered a common food allergen, although any food can trigger an allergic reaction.

Spinach is a healthy vegetable that contains high amounts of vitamin A , vitamin C, folate, iron and magnesium. When you don't have fresh spinach, frozen spinach is a great alternative.

Like other dark green, leafy vegetables, spinach is a nutritional powerhouse. Because all methods of cooking destroy some nutritional value, the best way to maximize nutrient intake is to eat fresh spinach raw.

Bananas turn brown because of a simple oxidation process. Oxygen oxidizes enzymes, according to food science professor Lynne McLandsborough in a July 2007 article for "Scientific American." This means that as soon as you cut a banana open, the pulp starts reacting to the air and turning brown.

During pregnancy, you generally need a little more than the recommended daily allowance of vitamins and nutrients to make sure your baby grows healthy and strong. This doesn't mean extra servings of junk food, however. While your child grows, you need to feed yourself nutritious meals.

Don't let the similarities between cucumbers and zucchini confuse you. Even though both cylindrical vegetables are dark green with white flesh, they are distinctively different species. Both cucumbers and zucchini belong to the Curcurbit family, which also counts gourds, melons, pumpkins and squash among its members.

In certain instances, what you eat and drink can change the color of your urine. Certain foods, such as carrots, rhubarb and juices can influence the color of your urine. Urine normally has a yellow hue but some foods, and even vitamins, can cause your urine to turn yellow, dark brown or fluorescent green.

Sweet potatoes are root vegetables harvested in warm climates, including Central and South America and some southern North American states. Overall, they’re healthy vegetables that are low in sodium, fats and cholesterol and a good source of fiber and vitamins A, B-6 and C.

Kale, collard greens and Swiss chard are three varieties of cooking greens. Curly leaved kale is often added to potato recipes. Collard greens, or collards, are popular in Southern cuisine. Both are members of the cabbage family. Swiss chard has thick, dark leaves and a flavor similar to spinach.

The fibrous flesh of spaghetti squash resembles long noodles after cooking and shredding. Although the squash noodles differ in flavor from traditional flour-based pasta noodles, you can use them in much the same way as pasta.