6. Assessment of food consumption and nutrient intake

Abstract

This chapter takes a comprehensive look at the techniques, strengths, and weaknesses of approaches to estimating food consumption and nutrient intake at the household and individual level. At the household level, it provides a detailed description of the methods available and the ways in which the data can be interpreted for epidemiological purposes, including techniques for estimating the distribution of food consumption and nutrient intake in individuals when data are collected at the household level. Similarly, it describes in detail the techniques for estimating food consumption and nutrient intake at the individual level, and focuses strongly on the repeatability and validity of measures, including an analysis of the sources of error such as portion size estimation, day-to-day variations in diet, estimates of the frequency of consumption, and the determination of current and past (relevant) diet. It addresses issues of under-reporting and energy adjustment, and concludes with an analysis of the effects of measurement error on validity.