Maximising satiety through manipulating expectations sensory quality and nutrient content.

Understanding the processes which promote satiety and so decrease the risk of overeating and a consequent positive energy balance are critical to our future ability to counteract the worldwide rise in the incidence of obesity. The traditional view of satiety is that suppression of appetite after eating arises from physiological effects of the ingested nutrients. However, while it is clear that nutrients do generate satiety signals, there are many aspects of satiety that cannot be explained simply as an effect of nutrient ingestion. For example, nutrients ingested as beverages generate weak satiety, whereas nutrients in a different liquid context (soup) generate strong satiety. This implies that something about the context in which nutrients are consumed is critical to the subsequent experience of fullness. Taking a more cognitive view, this research considers the extent to which consumer expectations about how filling a food will be may modify satiety. Thus a beverage may be consumed on the expectation of reduced thirst but not satiety, thereby leading to a failure to attribute physiological satiety cues generated by the drink nutrients to the actual drink product. Conversely, if the expectation is that a food will lead to strong feelings of fullness, this may lead to greater suppression of appetite than that generated by the same nutrients in the absence of expectations. Preliminary data in our laboratory are consistent with this view: protein was more effective in suppressing appetite when consumed in a context which was consistent with satiety than on its own. This research builds on this finding in a 3-phase programme designed to test the principle that expectations interact with physiological cues to modify satiety and so direct consumer behaviour. To achieve this, in Phase 1 we explore for the first time how expectations generated by label information and sensory quality modify the satiating effects of protein both in a snack and breakfast context. These experiments will first identify effective expectation manipulations and then examine their impact on satiety both when a product is first encountered and after repeat consumption. To ensure the outcome is both consistent and relevant to real-life behaviour, separate studies will use more controlled laboratory tests of eating and more naturalistic studies in a quasi-restaurant setting. The outcome of this 2-year Phase will be a clear test of the concept that expectations may interact with post-ingestive cues to generate satiety. How these expectations may modify actual physiological satiety responses will be tested in Phase 2, which examines how expectation-nutrient interactions modify the release of satiety hormones. As with Phase 1, these effects will be tested both acutely, and as a function of learning about the product as a consequence of repeated consumption. Finally, Phase 3 explores the utility of these findings for food product development by examining the effects of extended home consumption of products designed to generate maximum satiety through combinations of expectation and nutrient content. Separate home consumer trials will be run with the snack and breakfast products developed in Phase 1 and 2, and outcome measures will include effects of consuming high-satiety products on overall energy intake, and consumer evaluations of the products in terms of acceptability and future purchase intentions. The overall outcome of the programme will be both a detailed evaluation of the interaction between consumer expectations and physiological controls of satiety for the first time, and the use of such interactions to formulate new design rules for the development of future food products that generate consumer-perceivable satiety benefits.

Satiety involves integration of cognitive, oral, & post-ingestive signals. However, aspects of satiety remain puzzling, including the ineffectiveness of beverages to generate satiety. One possibility is that expectations about likely effects of consumed items on satiety interact with actual nutrient effects. If so, increasing expectations that products will be satiating should magnify effects of ingested nutrients, improving appetite regulation, and this is explored here. In Phase 1 optimal manipulations of satiety expectations, sensory quality & levels of nutrient that generate satiety, will be established, and how combinations of satiety expectations (through product labelling and sensory quality) & nutrient content interact will be explored. Studies concentrate on protein-based satiety only since this appears more effective than other macronutrients in generating satiety. Phase 1 will use both a mid-morning drink-preload manipulation, and a modified breakfast in a naturalistic environment, to determine the extent to which expectations modify satiety both acutely (Experiments 1-4), and as a consequence of repeat consumption (to test for learning: Experiment 5). How expectation effects relate to release of satiety hormones is tested in Phase 2, with Experiment 6 examining acute effects of manipulated expectation and Experiment 7 exploring effects of learning. Phase 3 explores longer term effects of repeated consumption of products optimised to generate satiety, with 2-week interventions where either an optimised satiety product or control consumed at home either as a mid-morning snack (Study 1) or breakfast (Study 2). Outcome measures include daily energy intake, appetite post-consumption and consumer evaluations of the products. Overall, the project outcome could explain discrepancies in the literature on the nature of satiety and offer the food industry new design rules for development of food products with consumer perceivable benefits on appetite control.

Who will benefit from this research? The major beneficiary will be those sectors of the food industry who are engaged in marketing and production of new food products where satiety is an issue and broader sectors of the food and catering industries who are responding to increased legislation on food labeling. The potential for the design rules for enhancing satiety to impact on weight control also has relevance for health professionals interested in weight control, and the general public. How will they benefit? The outcome of this proposal will be guidance on how the way a product is described, the immediate sensory quality the consumer experiences and post-ingestive nutrient effects interact to generate satiety. This may lead to new design rules for optimising the impact of foods on consumer experience of satiety, and this will be the primary benefit to the food industry. The theoretical and empirical knowledge gained from this research will enhance our understanding of the nature of satiety, with the potential to cause a paradigm shift away from the predominant nutritional/physiological interpretation of satiety to one taking a more cognitive view point. Understanding how consumers experience satiety will have benefits for health professionals designing weight control programmes, while the increased understanding of how labeling may modify satiety expectations will help sectors of the food and catering industries who will be introducing more detailed food labeling in response to legislative requirements in response to the current obesity crisis. What will be done to ensure that they have the opportunity to benefit from this research? Those sectors of the food industry who are part of DRINC will be made aware of the programme through the bi-annual DRINC meetings, and through direct engagement with key scientists in those companies who have shown particular interest in this research. We have also targeted the international Sensory Science Pangborn conference as a forum where we can present this work in an industry-focused environment. In addition, we plan to publish reviews of this work in trade journals which are widely read by the food and catering industries. The empirical research will also be presented at leading international conferences and in high quality academic journals to ensure this work is accessible to academic users, and inclusion of one obesity-related conference later in the programme will bring the work to the attention of health professionals with interests in weight control. The PI (Yeomans) has a track record both of high rates of publication and impact of his research, and a history of engagement with industry, both of which will enhance his ability to ensure impact. The knowledge and contacts of Co-applicant 1 (Rodgers) with the catering industry will allow us unique links through which to both bring the outcome of this work to that industry but also to explore future collaborations aimed at maximising the benefit of this work in that context. In terms of exploitation of the outcome, it may be possible to license the design rules generated by this work, and the PI will explore this possibility with colleagues in the University of Sussex Enterprise team.