[Validity of nutrition survey methods].

The aim of all dietary surveys is to discover what the persons under investigations are in habit of eating. They could be used to collect data on a single individual and on several hundred of individuals. There are two types of methods used: --evaluation of global consumption, --precise dietary studies. Additional studies research conscious and unconscious factors of dietary consumption. Whatever the aim, dietary patterns are used to trace trends both retrospectively and prospectively. But the nutritionist must be aware of limitations of the methods and be constantly improving them. It is imperative, therefore, that critical evolution be made at every stage of the procedure. The interest of those studies is to identify the current nutrient intake of a group or an individual likewise during a longer period, so that we can define the evoluation and perhaps the reason behind them. In epidemiological work, they are a part of the whole given data. They could permit the evaluation of correlation with clinical or biological parameters or with a particular disease.