Differentiate among the methods of collecting food consumption data at the national, household, and individual levels

Answer 1

The primary method of assessing the available food supply at the national level is based on food balance sheets. Food balance sheets measure the food available for consumption from imports and domestic food production, less the food "lost" through exports, waste, or spoilage, on a per capita basis. It is not a measure of actual food consumption, but availability.
Methods of assessing household food consumption consider the per capita food consumption of the household, taking into account the age and sex of persons in the household (or institution), the number of meals eaten at home or away from home, income, shopping practices, and other factors.
Four different methods used to assess food consumption at the individual level include: diet history, 24-hour dietary recall, food record or diary, and food frequency questionnaire. Dietary recalls are appropriate for assessing the intakes of groups of people, but a single 24-hour recall may not give an adequate picture of a specific individual's usual intake. Food records are often considered the best method of assessing dietary intake, but they are time consuming, and the results may not be accurate if subjects modify their eating habits during the time of the study. Diet histories can provide detailed information, but they require subjects to make judgments about their usual food habits. Food frequency questionnaires provide less detailed information, but are well suited for use with large groups.