Decisions about portion size have a major influence on the number of calories we consume. And it appears that our expectations of satiety – how filling a food is – can have a major influence on how much we put on our plate and, ultimately, how much we eat.
Professor Jeff Brunstrom at the University of Bristol has been investigating the origin of these expectations, as part of a research project supported by the Diet and Health Research Industry Club (a partnership led by BBSRC with the Medical Research Council, the Engineering and Physical Sciences Research Council and 13 industry members) in order to understand how they might be learned over time.
The study has led to the development of a new methodology – the consumer expectation toolbox – which has already been used by industry, to explore the expected satiety of products, and in a clinical setting, to assess food reward and expected satiety before and after gastric surgery.
Encouraging good eating behaviour
Increasingly, commercial foods differ in their size, energy density, macronutrient composition etc. As part of a new project funded by BBSRC, Brunstrom will build on his body of evidence by looking at the effects of variability in our dietary environment and whether this compromises our capacity to regulate our energy intake.
And in a second BBSRC-funded project (LINK), Prof. Brunstrom will be working with Nestlé to explore whether patterns of eating behaviours (bite size, eating rate, inter-bite interval, etc.) manifest themselves in the expected satiety of foods from meal to meal. The research brings together Nestlé's expertise in eating behaviour research with the Brunstrom lab's approach to understanding portion size and expectations of satiety.
"For a long time, researchers have suspected that obesity is associated with a particular eating style, eating quickly in particular," says Brunstrom. "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 aim to expose the mechanism that underlies this effect.
"By understanding eating behaviour, we hope this research will lead to new ways to prevent and treat obesity either through modifying eating behaviours directly or by developing foods that encourage specific patterns of eating,"