Professor of Experimental Psychology, University of Bristol

My research focuses on psychobiological controls of food choice and food intake. This area is fundamental to the study of obesity. Animal models indicate that associative learning plays a critical role in dietary behaviour and my work has pioneered the study of this process in human appetitive research. Researchers with an interest in energy balance have tended to focus on biological and psychological processes that terminate a meal.

My work suggests that in humans, the relevance of these prandial events has been overstated and that meal size is very often determined before a meal begins. My recent work shows that to understand energy intake it is critical that we appreciate the cognitive activity associated with decisions about portion size. This approach has wide ranging implications for the study of dietary control.

In particular, it would appear that ‘expected satiation’ and ‘expected satiety’ are key drivers of the number of calories that we put on our plate (perhaps even more important than palatability). These ideas were developed as part of a BBSRC-funded project (DRINC initiative, 2009-2012) that explored the origin of these expectations and how they might be learned over time.

Currently I am a PI working on two further BBSRC-funded projects (36 months). The first of these is exploring the effects of variability in our dietary environment. Increasingly, commercial foods differ in their size, energy density, macronutrient composition, and so on. My group is helping to determine whether these sources of variability compromise our capacity to regulate our energy intake.

In a second BBSRC-funded project (LINK) I am working with an industry partner (Nestlé) to explore the effects of eating behaviour on food intake. For a long time, researchers have suspected that obesity is associated with a particular eating style, eating quickly in particular. Under controlled conditions it would seem that eating at a slower rate produces both an increase in self-reported fullness and a reduction in meal size. Moreover, epidemiological studies indicate that eating rate is a good predictor of bodyweight. For the first time, my team is exposing the mechanism that underlies this effect. In turn, this work has the potential to lead to novel treatments for obesity and the design of foods that reduce our calorie intake from meal to meal.

In January 2014 the NBU started a 5-year EU-funded project called Nudge-it. The factors that drive food choice are poorly understood. I am working with other partners in the EU to develop and implement novel scientific approaches to better understand this problem and provide evidence-based solutions.

In the NBU we tend to study people who have only ever been exposed to a Western diet. An ongoing concern is that we might overlook important detail or, worse still, we might draw general conclusions that don’t translate to other cultures. To begin to address this concern since 2013 we have been conducting field research involving the Samburu - a population of semi-nomadic pastoralists who live in a remote area of Kenya. No ‘processed’ foods and certainly no ‘diet’ products or diet sodas are consumed! This makes the Samburu an ideal population to study because they can help us to understand the comparative effects of exposure to dietary variability and complexity in our own dietary environment (a central theme of an ongoing BBSRC-funded project). You can find out more about this project here.

More generally, I have an interest in the relationship between cognition and dietary control. For example, recent projects have explored the interplay between attention (focused and divided) and meal size. I am also interested in understanding the ‘reactivity’ that is experienced after exposure to the sight and smell food and how heightened reactivity might promote overweight and obesity.

Experience

  • –present
    Professor of Experimental Psychology, University of Bristol