The last on this list is perhaps one of the most nutrient-dense foods around. Spinach is loaded with ample vitamins, minerals, vitamin K, fiber, as well as a bit of protein (not a complete protein). In addition, spinach is low in calories, low on the glycemic list, and also low on your glycemic load, making this one of the best overall foods around. Spinach is great in a salad and can even be a great addition to your early morning smoothie after your workout. Consider adding at least one serving of this crucierous vegetable to your diet each day for best results.