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NutrInsight • Satiety: from appetite sciences to food application
Satiety: from appetite ScienceS to food application
1 SATIETy REguLATIoN AND MEASuREMENT: LINkINg PHySIoLogy AND BEHAVIouR
Pr John E. Blundell, Director of the Institute of Psychological Sciences, University of Leeds, UK
Satiety is one component of a ‘system’ that influences the expression of appetite. In turn, food intake is under the control of a number of alternating stimulatory and inhibitory influences. The physiological need for energy and nutrients periodically generates hunger signals that elicit the acquisition and intake of foods. In addition to physiological, homeostatic stimuli of food intake, the human environment also generates hedonic motivation for food intake. These stimulatory influences are counteracted by inhibitory processes that stop eating at one particular eating event, and then inhibit further eating in the hours that follow an eating episode.
1.1 Satiation and satiety
Definitions
Satiation has to do with the inhibition of the motivation to eat that occurs during one meal or one eating episode. The stimulatory influences of physiological (hunger) and sensory factors are at maximum level at the beginning of eating. Progressively, as the eating episode progresses, many inhibitory influences (sensory, gastric, hormonal, neural) increase in intensity and finally bring eating to an end. These processes determine meal size.
Satiety has to do with the inhibition of eating that occurs at the end of one eating episode, under the influence of various determinants, and particularly the effects of the foods ingested. Numerous characteristics of foods have been shown to play a part in satiety (sensory characteristics, weight, energy, nutrient content, among others). These post-eating inhibitory influences induce varying intensities and durations of satiety. In addition they can moderate the amount of food consumed in later eating episodes.
Acting together, the related processes of satiation and satiety help to control the size of eating episodes and the frequency of eating. While defining satiation and satiety is easy, the actual processes are highly complex.
The “Satiety Cascade“
These inhibitory influences can be conceptualized through the operations of the “Satiety Cascade” first described more than 20 years ago [Blundell, Rogers & Hill, 1987] but subsequently modified by many researchers. Figure 1 provides a recent representation of established factors involved in satiety [Blundell et al., 2010]. The satiety cascade illustrates a number of factors contributing to satiation. Sensory factors such as taste, aroma, and food texture stimulate and then inhibit intake, via sensory-specific habituation to the characteristics of the ingested foodstuffs. In parallel signals from the gastro-intestinal tract at the time of
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