Abstract
<jats:p>This chapter discusses assessment method practices for dietary intake and hydration status in different settings. Dietary assessment methods are used for a variety of purposes, from individual assessments in clinical situations, through to use in epidemiology. The chapter focuses on assessment methods suitable for individual intakes. A 24h recall determines intake during the preceding 24 hours and can be recorded on paper or using interactive computerised software. The dietary history provides a representative pattern of usual intake and is interview‐administered only and may be used in clinical practice. Food frequency questionnaires consist of a list of specific foods or food types associated with the frequency of consumption to record average consumption over the previous month or year. Dehydration, clinically defined as the loss of body water, with or without salt, faster than the body can replace it, is a common but often misdiagnosed fluid and electrolyte disorder.</jats:p>