Nutritional Assessment and Profiling: Dietary
Dietary Assessment on the Household Level
Household food consumption is the amount of food available for consumption in a household, not counting food eaten away from home unless it was taken from the home. Food consumption per capita is calculated in terms of income level, family size, region, and other socio-economic characteristics. Estimates can be made of nutrient intake per capita by multiplying average food consumption data by nutrient values of foods from nutrient data tables.
Food Account Method
In this method, a person in the household deeps a daily record of all food entering the household during a given time period, usually seven days. Food is not counted if it is consumed outside of the home, discarded as plate waste, or fed to pets. The method makes fairly little demand on the household recorder, and is inexpensive to use for a large population. The resulting data provides information on the mean food consumption and selection patterns of a population.
In this method, an interviewer asks a person in the household to recall all food used by the household on an as-purchased basis. Quantity and price of foods are noted for a certain period of time, usually one to seven days.
The inventory method entails taking an inventory of all food in a household at the beginning and end of a specified period, usually one week. The types and weights of all foods brought into the house are recorded daily during the period. Waste is subtracted either by using a general figure of 10% wastage or by actually collecting and weighing the foods discarded. The number and age of household members is collected, allowing for estimation of food consumption per person.
Household Food Record Method
In the household food record method, members of the household, or field workers, keep records of all foods consumed at each meal by weight, which is measured before division into individual servings. Recipe ingredients are recorded for mixed foods. A 10% wastage factor can be used to subtract food not consumed. If food is weighed consistently, this is the most accurate method of recording household food intake but puts a large burden on the people in the household.
Telephone surveys can be used to obtain information on household food consumption or for information on specific foods. This method is generally less expensive than other methods.
Use of Household Food-Consumption Data for National Food-Consumption Surveys
Many countries use household methods for their national food consumption surveys. Sampling design must be carefully planned so as to obtain a representative sample of the nation, accounting for influences of socio-economic status, region, season, and weekends.
Every ten years the U.S. conducts nationwide household food consumption surveys using the list-recall method for a period of seven days. Surveyors collect information on socio-economic status, shopping practices, number of meals and snacks consumed outside of the home, and food-assistance program participation. Surveyors also collect information on food intake of individual household members using a 24-hour dietary recall, followed by two days of food records. Participants are asked questions about eating patterns, use of dietary supplements, weight, height, and general health status.