Sweet potatoes are a Native American plant that was the main source of nourishment for early homesteaders and for soldiers during the Revolutionary War. These tuberous roots are among the most nutritious foods in the vegetable kingdom. They are packed with calcium, potassium, and vitamins A and C. This is why one colonial physician called them the "vegetable indispensable." Sweet potatoes are often confused with yams, but yams are large, starchy roots grown in Africa and Asia. Yams can grow up to 100 pounds and are rarely available in American supermarkets. Nutritionally, sweet potatoes greatly outweigh yams. Because of the common use of the term "yam," it is acceptable to use this term when referring to sweet potatoes. Sweet potatoes contain an enzyme that converts most of its starches into sugars as the potato matures. This sweetness continues to increase during storage and when they are cooked.

Squash are fleshy vegetables protected by a hard rind. They belong to the plant family that includes melons and cucumbers. Among substances present in summer squash are these two phytochemicals, coumarins and flavonoids. The skin and rind of summer squash are rich in the nutrient beta-carotene, but the fleshy portion of this vegetable is not. To gain the full nutritional benefits of this vegetable, the skins or rinds must be eaten.

Spinach is believed to be of Persian origin and introduced into Europe in the 15th century. Since the early 19th century, spinach has been a versatile and commonly used vegetable in the United States. Eating and preparing spinach is simple and easy, since it tastes good raw or cooked. Spinach can be found fresh, frozen, or canned; it can be easily incorporated into many dishes. Its versatility makes it easy to serve raw in salads or sandwiches or as a complement to soups, meat, fish, or other vegetable dishes. In addition to being tasty, spinach’s popularity stems from its high nutritional value. Not only is spinach low in calories, it is also a good source of iron and essential nutrients such as vitamins A and C, minerals, and fiber. Spinach also contains 3 grams of protein per serving.