Appetite control: methodological aspects of the evaluation of foods

Abstract

This report describes a set of scientific procedures used to assess the impact of foods and food ingredients on the expression of appetite (psychological and behavioural). An overarching priority has been to enable potential evaluators of health claims about foods to identify justified claims and to exclude claims that are not supported by scientific evidence for the effect cited. This priority follows precisely from the principles set down in the PASSCLAIM report. The report allows the evaluation of the strength of health claims, about the effects of foods on appetite, which can be sustained on the basis of the commonly used scientific designs and experimental procedures. The report includes different designs for assessing effects on satiation as opposed to satiety, detailed coverage of the extent to which a change in hunger can stand alone as a measure of appetite control and an extensive discussion of the statistical procedures appropriate for handling data in this field of research. Because research in this area is continually evolving, new improved methodologies may emerge over time and will need to be incorporated into the framework. One main objective of the report has been to produce guidance on good practice in carrying out appetite research, and not to set down a series of commandments that must be followed.

Figure 1

Figure 2

Model of Eating Behaviour. From this perspective eating behaviour is governed by three factors, metabolic factors that drive hunger and satiation, and satiety, and sensory factors that drive food choice. Repeated exposure to one sensory signal will cause a drop in reward value for that particular sensory signal (see also part on sensory specific satiety within this chapter), and cause a shift to the choice for another foods. In the brain the sensory signals of food are linked to the metabolic consequences, conditioning our eating/nutrition pattern. In addition, there are cognitive factors that shape our eating habits.

Fig. 3

Scheme reflecting the effect of liking on wanting (desire) and the intermediary influences of psycho-physiological state, and external stimuli (learned cues). Solid lines reflect proximate drivers, dashed lines are underlying processes. (Source Mela, 2006 (6))