A method for estimating food intake. Two frequently used interview methods are the 24-hour recall method and the dietary history method. In the 24-hour recall method, a complete description of the total food intake during the 24 hours preceding the interview is requested. As with the 2-day record method, a single 24-hour recall does not give a good estimate of food consumption by individuals because of the large day-to-day variation in food intake. With the dietary history method, respondents are asked about their usual food intake during a specific period of time, usually the 2-4 weeks preceding the interview. This method gives a better indication of the usual dietary intake by individuals. Since a dietary history interview takes about 1-2 hours, this method cannot be applied in studies in which many thousands of people participate.