Most of the food that the men ate was canned corn beef, bread and biscuits. By the end of 1916 flour was in such short supply that bread was being made with dried ground turnips. The main food then changed to pea soup with a few lumps of horse meat. The supply of food was so low that the cooks had to use things like nettles in soups and stews. The catering staff even put the food in petrol cans and jam jars.
All men carried emergency food called iron rations. This was a can of bully beef, a few biscuits and a sealed tin of tea and sugar. These iron rations could only be opened with the permission of an officer. This food did not last very long and if the kitchen staff were unable to provide food to the soldiers they might be forced to retreat from land they had won from the enemy.
In my opinion this was bad quality food and it is bad that the food was in such short supply. I think that it is bad that they had to have permission to open there emergency rations even if they were not with an officer.