University of Roehampton ‘Live Science’ project “How much do you like to eat?”:
Venue: Science Museum, London, September 2015.
Do you find it easy to control what you eat? Or do some foods tempt you so much that you can’t
resist them? Is it the foods, or is it you? Researchers from the University of Roehampton, London,
want to understand why some people may overindulge in certain foods and how this relates to our
personality and genes.
The rationale of this project is to understand predictors of individual differences in
susceptibility to overeat, particularly of energy-dense foods (typically high in fat), and thus risk of
becoming obese. This is in the context of the rising prevalence of obesity being of considerable
concern to the nation’s health and economy (Public Health England, 2015). At the same time,
nutritional, medical and behavioural scientists are debating the importance of different proportions,
and forms, of macronutrients (protein, carbohydrate, fat) in foods, and their effects on sensory
qualities and energy density, for food choice, appetite control and weight maintenance
(Hetherington et al., 2013; Buckland et al., 2015). For example, it is known that protein-rich foods
tend to suppress appetite most effectively (Buckland et al., 2015), whereas energy-dense foods
often lead to greater energy intake (Rolls et al., 2005).
On the other hand, sweetness, and thus sugar content, of foods contributes to their
palatability, and there is an ongoing debate as to whether some people are particularly susceptible
to ‘craving’ sweet foods (Gearhardt et al., 2014; Ziaudeen & Fletcher, 2013). Even so, there is little
evidence that sugary foods (as opposed to sugary drinks) contribute to obesity (SACN, 2015); rather,
the interaction of sweetness with other properties in particular fat content may be critical. Several
studies have proposed that people at risk of obesity may find it particularly hard to resist such foods
(e.g. ice cream, milk shakes), perhaps because of genetic tendencies to be sensitive to rewarding
experiences (Faith et al., 2013; Morris et al., 2014).
Extending this concept of lack of control, deficits in inhibitory control and impulsive
tendencies have been found to be associated with adiposity in children and adults (Gerlach et al.,
2015). Studies of large twin cohorts have shown not only that simple measures of a child’s appetite
tendencies (enjoyment of food; eating rate; satiation insensitivity) are associated with adiposity but
that these behavioural traits are substantially inherited (Faith et al., 2013). Although the precise
genetic mechanisms for this are not yet known, the strongest gene association with obesity is for
polymorphisms linked to the FTO gene, which appear to have effects on brain function (Loos & Yeo,
2014). Moreover, it is possible that eating rate may be partly a result of competition from siblings,
as well as influence by FTO variant (Shihab et al., 2014) and this aspect will be examined here using
information on number of siblings and birth order.
Thus this project will incorporate a combination of questionnaire items designed to capture
traits linked to obesity risk and brief computer-based behavioural tasks including food images, that
assess risk-taking, reward sensitivity, food preferences, and interactions between food nutritional
and sensory characteristics and appetite. In addition, we will assess height, weight, and waist
circumference (as the more reliable simple measure of adiposity-related risks to health; WHO
Report, 2008).