The grain is mentioned first, as it is the main source of food. Examples of grains are: wheat, rice, beans and lentils.
Next in order of importance are grapes; as they can be consumed as the main nutrition such as wheat and also as a fruit.
Herbage: The fresh plants that human beings eat, such as: Radish, watercress and parsley.
Olives: These are a rich source of oils and fatty substances.
Palm trees: These are a rich source of sugary substances.
In this manner, Allah (swt) combines for you all of these elements of nutrition which the earth produces for you by the Power of Allah (swt).