Satiation, Satiety and the Control of Food Intake

Theory and Practice

John E Blundell, France Bellisle

• Publisher: Woodhead Publishing
• Year: 2013
• Print ISBN: 9780857095435
• eBook ISBN: 9780857098719
• Topic: Technology & Engineering
• Subtopic: Food Science
• Index: Technology & Engineering

With growing concerns about the rising incidence of obesity, there is interest in understanding how the human appetite contributes to energy balance and how it might be affected by the foods we consume, as well as other cultural and environmental factors. Satiation, satiety and the control of food intake provides a concise and authoritative overview of these areas. Part one introduces the concepts of satiation and satiety and discusses how these concepts can be quantified. Chapters in part two focus on biological factors of satiation and satiety before part three moves on to explore food composition factors. Chapters in part four discuss hedonic, cultural and environmental factors of satiation and satiety. Finally, part five explores public health implications and evaluates consumer understanding of satiation and satiety and related health claims.- Provides a concise and authoritative overview of appetite regulation- Focuses on the effects of biological factors, food composition and hedonic, cultural and environmental factors affecting appetite control- Discusses implications for public health

Part I

Introductory issues

1

Satiation, satiety: concepts and organisation of behaviour

F. Bellisle, Université Paris 13, France

J.E. Blundell, University of Leeds, UK

Abstract:

‘Satiation’ and ‘satiety’ are key terms that have come to be widely used to help understand processes involved in appetite control and, in turn, to account for changes in food consumption that may lead to obesity. Taken together, satiation and satiety are major components of the Satiety Cascade. In theory building the terms have different levels of meaning, ranging from descriptors through constructs to causal mechanisms. This chapter provides some landmarks in the development of the use of the terms.

Key words

satiation

satiety

obesity

appetite

food intake

eating pattern

1.1 Introduction

This current period in the early part of the twenty-first century is an important and stimulating time to be discussing the notions of satiation, satiety and appetite control. Many people on the planet can be described as possessing large quantities of body fat – much of it incompatible with optimal health. Others are dealing with inadequate food and intolerable levels of hunger. In technologically advanced parts of the world people are obsessed with obesity; excess fat is often stigmatised. The food industry is simultaneously perceived to be part of the problem and part of the solution. Although human energy expenditure is generally far too low, food intake is unnecessarily high and conspicuous overconsumption is readily noticeable. These issues have social, economic and political implications. Can human appetite be managed to produce more healthy lives, and what do we need to know to bring this about? This book is not about everything that concerns appetite control (this would require ten books at least), but it addresses some key features of appetite science. It is worth debating whether or not the concepts of satiation and satiety can improve understanding of our own eating behaviour, and whether they can help to resolve a modern predicament in which we find ourselves – that is, the propensity of many humans to eat more than they biologically require. Why does this happen?

1.2 Satiety and satiation in the scientific literature

Humans are omnivores. Unlike herbivores or carnivores, whose food sources are usually quite restricted, omnivores have extended opportunities to eat a huge variety of materials. In addition, omnivores display episodic patterns of eating; the episodes, frequently called meals (or snacks), have a discrete size and duration. The pattern of human eating is heavily influenced by culture, but the episodic nature of eating is conserved. It is in relation to the episodic pattern of eating that the terms satiation and satiety have come to play a role in understanding the expression of appetite.

The terms which form the title of this book are frequently used in scientific discussions of appetite. How should these terms be understood?

In many cases satiation and satiety are given the status of causal mechanisms that influence the subjective expression of appetite (for example, sensations of hunger) and the structural form of eating behaviour. This is convenient in terms of theory, since it allows changes in eating behaviour to be explained by reference to adjustments in the strength of satiation and satiety. In turn, these two terms form the basis of the ‘Satiety Cascade’ – a concept that has influenced research and thinking about appetite.

Satiation and satiety are therefore terms that are loaded with explanatory intentions and refer to mechanisms believed to exert their effects through physiological and/or psychological processes.

1.2.1 Satiation and satiety as mere descriptors of behaviour

The terms can also be used more conservatively, without recourse to notions of causality, and can be defined operationally according to observed or measured changes in eating patterns. In this sense, satiation can be applied to effects that modulate the size of meals consumed, whereas satiety refers to effects observed in the post-meal period and reflects events occurring in the intervals between eating episodes. If this description appears a little prosaic, it is because some researchers prefer to adopt a cautious approach to motivational concepts.

1.2.2 Satiation and satiety as intervening variables

Intervening variables play important roles in psychological theory and they operate in the middle ground between mere descriptors and causal mechanisms. Some researchers (and theorists) prefer to use satiation and satiety as intervening variables that can explain changes in behaviour. However, such explanations are a theoretical convenience, and to have any causal legitimacy the constructs have to be tightly linked to events in biology or the environment that can be objectively measured. This is not a common use of satiation and satiety, but it is legitimate and it respects the logical status of the terms.

1.2.3 Satiation and satiety as mechanistic processes

More commonly, the terms satiation and satiety are used to embody true mechanistic processes that influence the pattern of eating behaviour and associated sensations. It is in this sense that most authors in this book have interpreted and used the terms. Accordingly, satiation and satiety can be understood with reference to biological processes that cause people to (1) begin eating; (2) maintain an episode of eating, and then bring it to an end; (3) generate a suppression of the motivation to eat (immediately after a meal); and (4) preserve the inhibition of eating for a given passage of time.

There are many opportunities to investigate and identify the mechanisms that contribute to these processes. For example: what are the key biological signals that the brain uses to control satiation and satiety, and therefore the behaviour of eating? A natural supposition is that appetite control is functional, that its purpose is to manage the amount of food consumed, and that satiation and satiety are two processes deployed to bring this about. This is a very reasonable proposal; however, it is not supported by all researchers, and there have been several demonstrations that control processes for energy intake can often be overridden, undermined or otherwise subverted. Therefore the question becomes: what is the nature of appetite control, and what aspects of food consumption are actually being controlled? Moreover, how strong are the processes of satiation and satiety that are critical to appetite control?

Also, it appears that satiation and satiety can be manipulated either deliberately or accidentally to adjust their potency and to change the pattern of eating and the amount ingested. Some factors could weaken satiation and satiety so as to allow more food to be ingested, promoting overconsumption. Some individuals may have intrinsically weak biological signals that render them susceptible to overeating through a delayed termination of meals or a more feeble suppression of post-meal hunger. Certain people may have ‘fragile satiety’, which allows the period of post-meal inhibition to be dissolved to allow eating when it would not normally be expected to occur. Conversely, there is a clear need to investigate how satiation and satiety can be strengthened in order to limit the amount of food taken in. This understanding has generated activity in the pharmaceutical industry to develop drugs targeted for satiation or satiety and, in the nutraceutical and functional food sectors, to identify specific properties of food materials or ingredients that up-regulate biological signals to prematurely trigger satiation or prolong satiety.

1.2.4 Satiation, satiety and body-weight control

The idea that satiation and satiety are endogenous processes that participate in the control of appetite is a plausible proposition, although not universally accepted. However, there is also a more controversial proposition tha...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributor contact details
• Woodhead Publishing Series in Food Science, Technology and Nutrition
• Part I: Introductory issues
• Part II: Biological factors
• Part III: Food composition factors
• Part IV: Hedonic, cultural and environmental factors
• Part V: Public health implications
• Index