Edible seeds include cereals (such as maize, wheat, and rice), legumes (such as beans, peas and lentils), and nuts. Oilseeds are often pressed to produce rich oils, such as sunflower, rapeseed (including canola oil).
Fruits are the ripened ovaries of plants, including the seeds within. Many plants have evolved fruits that are attractive as a food source to animals, so that animals will eat the fruits and excrete the seeds some distance away. Fruits, therefore, make up a significant part of the diets of most cultures. Some botanical fruits, such as tomatoes, pumpkins and eggplants, are eaten as vegetables.
Vegetables are a second type of plant matter that is commonly eaten as food. These include root vegetables (such as potatoes and carrot), leaf vegetables (such as spinach and lettuce), stem vegetables (such as bamboo shoots and asparagus).
Animals can be used as food either directly or indirectly by the products they produce. Meat is an example of a direct product taken from an animal, which comes from either muscle systems or from organs.
Food products produced by animals include milk produced by mammals, which in many cultures is drunk or processed into dairy products such as cheese or butter. In addition birds and other animals lay eggs, which are often eaten, and bees produce honey, a popular sweetner in many cultures.
Foods not coming from animal or plant sources include various edible fungi; such as mushrooms. Fungi and ambient bacteria are used in the preparation of fermented and pickled foods such as leavened bread, alcoholic drinks, cheese, pickles and yogurt.
Many cultures eat seaweed, a protest, or blue-green algae seaweed. Additionally, salt is often eaten as a flavouring or preservative; and baking soda is used in food preparation. Both of these are inorganic substances, as is water, an important part of human diet.
Due to climatic or topographic conditions, only 40% of the total area of the world can ever be used for cultivation of crop. Present day agricultural largely depend upon modern technological factors like the use of improved seeds, chemical fertilizer, pesticides and irrigation.
Through modem technology have proved a boon to our agriculture and have increased the yield of crop manifold, they have created a number of problems.
Many cultures have diversified their foods by means of preparation, cooking methods and manufacturing. This also includes a complex food trade which helps the cultures to economically survive by-way-of food, not just by consumption.
While humans are omnivores, religion and social constructs such as morality often affect which foods they will consume. Food safety is also a concern with food borne illness claiming many lives each year. In many languages, food is often used metaphorically or figuratively, as in “food for thought”.