The instrument used in the UK Government National Diet and Nutrition Survey (NDNS) is an A5 size estimated food diary completed over four days including both weekend days.

Participants are provided with a diary and asked to keep a record of everything they ate and drank over these four days, both in and outside the home.

The adult diary provides photographs of 15 frequently consumed foods as small, medium and large portion sizes; otherwise portion sizes are recorded in household measures or for packaged foods to note the weight indicated on the packet. Participants are asked to take into account leftovers when recording how much they consumed. Brand names and labelling are requested to be collected, and for homemade dishes, participants record on a separate page the ingredients and quantities along with the cooking method.

Participants also record where they were, who they were with and whether they were watching TV and/or sitting at a table for each eating occasion. After each day, participants record if their intake was typical for that day and details of any dietary supplements taken. The diary also contains questions about usual eating habits (for example, type of milk or fat spread usually consumed).

Diaries are coded and food intakes entered into a dietary assessment system (Diet In Nutrients Out or DINO has been used in NDNS).