It's an easy visual reference that shows whether your dinner plate is a healthy one: The brighter, more vibrantly colored the foods, the better they are for you -- especially when it comes to vegetables.
While it's true that vibrant vegetables like kale contain greater levels of vitamin K and other nutrients than their paler counterparts, like iceberg lettuce, it isn't a hard-and-fast rule [source: Erway]. Many pigment-challenged vegetables get a bad rap. The truth is, some phytochemicals that make vibrant vegetables good for you are also present in pale or white vegetables because some phytochemicals are colorless [source: Produce for Better Health Foundation].
Celery, for example, is so well known for its soft and soothing color that it's a popular moniker for interior paint colors and decorator fabrics. But don't assume this understated veggie is a weakling when it comes to nutrition. Celery is a nutritional powerhouse packed with vitamins, calcium, and phthalides that can lower blood pressure. Cabbage is another example of a pale vegetable that can hold its own against bell peppers and green beans. Cabbage is high in vitamin C and has been connected to a lower cancer risk. So have onions, which are rich in compounds that help prevent heart disease. And cauliflower, despite its lack of color, has lots of isothiocyanates, indoles and vitamin C to help fight cancer [source: Nutrition and You].