A Unilever scientist has called for a re-evaluation of the link between over-eating and obesity by challenging the traditional view that the pleasure of taste is the driver for over-consumption.
David Mela, a senior scientist from the Unilever Food and Health Research Institute in the Netherlands, wrote in the journal Appetite (Vol. 47, pp. 10-17) that this distinction has "important implications for further research" right across the food industry; from sensory food scientists to researchers into appetite, from food developers to food marketers.
Much research into food choice, both academic and industrial, is based on the assumption, said Mela, that taste is the driver for food selection and consumption. In other words, food choice is based closely or directly on the pleasure of eating.
But such an assumption does not fit with a growing body of behavioural and neurophysiological data that obesity is linked with increased motivation for consuming food, without necessarily deriving greater pleasure derived from the taste-aroma experience of eating.
A distinction should be made, said Dr. Mela, concerning "liking" of food, and "wanting" of food. "Liking" of food implies deriving pleasure from eating it, whereas "wanting" a specific food implies fulfilling a desire that may not be derived from pleasure.
Terms such as "craving" and "dependency" for foods have led to parallels between food and drugs that, said Mela, is not surprising since both share common neurological reward pathways that's to say, the reaction of the brain to certain drugs and food is similar.
Bearing in mind these neurological responses, Mela said "implicit tests or other sorts of behavioural tasks or physiological correlates are probably needed to isolate and characterize the 'liking' versus 'wanting' discrimination for food in humans."
Therefore, the key to understanding "why we want to eat what we want to eat" is based on three things, said the author, all of which should be considered to providing help and guidance to the obese or people at risk of obesity.
These include: physiological cues (including but not exclusively hunger and thirst); anticipated pleasure; and external cues, which may be learned but could also include mental function that may unconscious.
And accepting and understanding these distinctions has important implications for a wide range of scientists involved in food science and/or guidance against obesity.
Perhaps the most obvious impact could be for scientist actively involved in the sensory measurement of food. "In order to understand why certain food stimuli are liked and also have a high and sustained desired frequency of consumption, this field should escape the bounds of its traditionally narrow focus on immediate oro-sensory responses," said Mela.
For commercial food developers, Mela suggests that changes and decreases to product purchasing or food preferences over time may not be due to poor or loss of oro-sensory quality, but from "product boredom (a change in "wanting"?)".
"The challenge in relation to weight control remains to improve the quality and attractiveness of lower energy foods, and ensure they are not just "liked", but also "wanted"."
Food marketers should also recognise the distinctions, and "take responsibility to ensure that they are not unduly adding to the environmental stimulation to eat inappropriately."
There also needs to be a change in the consumer perception, said Dr. Mela, that "in order to be good for you, it cannot taste nice"
Such an approach will "get us nowhere," said Mela, in moving consumers to a healthier and balanced diet.
"The challenge is to understand the drivers of variance in eating behaviour, and to apply this knowledge to food development, marketing, and public health guidance in ways that make healthy, appropriate eating something that is liked, desired, and preferred," concluded Mela.
Over 300m adults are obese worldwide, according to latest statistics from the WHO and the International Obesity Task Force. About one-quarter of the US adult population is said to be obese, with rates in Western Europe on the rise although not yet at similar levels.