Convenience food is food that has been prepared in a factory and is sold by shops in cold, chilled or frozen form. It is often already cooked and therefore needs only heating. Chilled foods often need a small amount of cooking, as, for example, the pizza in the video below, which needs to be cooked for 10 minutes in an oven. The lasagne in the picture above simply needs reheating.

Convenience foods can be excellent or awful. This is because there is just as much skill in making good convenience food as in any other type of cooking. There are also special challenges. For example, the food has to stay fresh for days (chilled) or not lose its texture if frozen.

To achieve this, convenience foods often use fat instead of water, and a range of preservatives such as salt and sugar.

There is nothing wrong with these preservatives as such - biscuits (which is a kind of convenience food) last a long time because the 'moisture' is actually fat (butter). Salt also brings out the flavour in food.

Convenience foods may be more appetising than a person can make for themselves, and the time to get the food ready is much shorter. All that has to be checked is the amount of salt and fat to ensure it is balanced out by other parts of a diet. So, for example, a convenience pizza containing a lot of salt can be balanced by a salad with no salt.

Convenience foods are popular with shops because they can be sold for much more than the raw ingredients.