Appetite, Satiety, and Eating Behaviour in Assessment

Appetite is the desire to eat, and satiety is the sense of fullness that ends a meal; together with broader eating behaviour they govern how much food a person actually consumes. Assessing them, including the use of simple appetite questionnaires, helps clinicians identify people at risk of declining intake and weight loss before deficits become severe.

Definition

Assessment of appetite, satiety, and eating behaviour refers to evaluating a person's desire to eat, sense of fullness, and patterns of eating in order to anticipate changes in intake and identify nutritional risk.

Scope

The topic covers the assessment of appetite, satiety, and eating behaviour as predictors of intake and nutritional risk, the concept of anorexia of ageing, and the use of brief appetite questionnaires. It is a reference description of assessment concepts and does not provide appetite-stimulating treatments or individualised dietary plans.

Core questions

• Is the person's appetite reduced, and is intake declining?
• How do satiety and eating patterns shape the amount eaten?
• Can simple appetite measures predict weight loss and nutritional risk?
• How does anorexia of ageing contribute to undernutrition?

Key concepts

• Appetite and the drive to eat
• Satiation and satiety (within-meal and between-meal fullness)
• Anorexia of ageing
• Appetite questionnaires as screening tools
• Reduced food intake as a malnutrition criterion
• Eating behaviour and meal patterns

Mechanisms

Appetite and satiety arise from interacting signals (gastrointestinal, hormonal, sensory, and central) that together regulate when and how much a person eats. When appetite falls or satiety comes early, intake declines, and sustained shortfalls lead to weight loss and depletion of reserves. In older adults, age- and disease-related changes can blunt appetite and accelerate fullness (the anorexia of ageing), making reduced intake a frequent pathway to undernutrition. Because self-reported appetite tracks with subsequent intake, brief structured appetite questionnaires can flag people likely to lose weight, and reduced food intake is itself incorporated as an aetiologic criterion in consensus malnutrition frameworks.

Clinical relevance

Appetite and eating-behaviour assessment helps anticipate declining intake and identify nutritional risk early, and reduced intake is part of standardised malnutrition criteria. This entry describes the assessment concepts; it does not recommend appetite stimulants, supplements, or specific feeding strategies, which require individualised clinical evaluation.

Epidemiology

Poor appetite and reduced intake are common in older, hospitalised, and chronically ill populations and are strong correlates of subsequent weight loss; simple appetite questionnaires have been shown to predict weight loss in community-dwelling and nursing-home older adults (Wilson 2005), reflecting the high burden of the anorexia of ageing.

Evidence & guidelines

Validation work shows that a brief appetite questionnaire predicts weight loss in older adults (Wilson 2005); the ESPEN geriatric clinical nutrition guideline addresses appetite and reduced intake among determinants of nutritional risk (Volkert 2019); and the GLIM framework includes reduced food intake or assimilation as an aetiologic criterion for malnutrition (Cederholm 2019).

History

Appetite has long been part of the clinical nutritional history, but interest in standardising its measurement grew with ageing populations and the recognition of the anorexia of ageing, leading to the development and validation of brief appetite questionnaires and the incorporation of reduced intake into formal malnutrition criteria.

Seminal works

• wilson-2005
• volkert-2019
• cederholm-2019

Frequently asked questions

Why assess appetite during a nutritional evaluation?

Because self-reported appetite tracks with how much a person will eat, assessing it, including with brief questionnaires, can flag people at risk of declining intake and weight loss before significant deficits develop.

What is the anorexia of ageing?

It is the age-related decline in appetite and earlier sense of fullness seen in many older adults, which can reduce food intake and contribute to undernutrition, making appetite assessment particularly relevant in this group.