Posted on Thursday 22nd August 2013
Animal studies have shown that high-fat and high-sugar foods have similar effects on the brain as do substances more usually associated with addiction, such as alcohol or drugs. The research also suggests these foods can cause similar problems, such as withdrawal symptoms or going to great lengths to obtain the food. Yet, the existence of food addiction in humans remains extremely controversial within the scientific community.
The development of a questionnaire by Yale University has allowed researchers to determine whether some people’s responses to food mirror those seen in substance dependence disorders and to diagnose ‘clinical addiction’ to foods. Based on studies using this questionnaire, fewer than one in ten healthy adults appears to have symptoms similar to those seen in drug dependence, although the prevalence is higher in people with weight problems and eating disorders.
Despite the controversy within the scientific community, many people happily admit to being ‘addicted’ to foods such as chocolate or bread. Scientists have not studied self-perceived ‘food addiction’, and it is unknown whether such ‘addicts’ are experiencing some degree of genuine substance dependence. In a study at the University of Birmingham, 303 psychology students were asked whether they believed themselves to be addicted to any foods, following which they answered a range of questions relating to their eating behaviour, dieting, body image, and whether they tended to do things in order to gain approval from others.
As with previous studies, the rate of ‘clinical food addiction’ was quite low, with only 7% of participants meeting the diagnostic criteria for a genuine substance dependence. In contrast, more than half (52%) of the students believed that they were addicted to some foods. Interestingly, however, their ‘condition’ was not just imaginary. Self-classified ‘food addicts’ had significantly different scores on all measures of eating behaviour, body image and personality traits from those people who did not believe they were addicted to any foods.
These findings suggest that self-perceived ‘food addiction’ is a real phenomenon, although one that does not encompass the clinically significant impairment or distress that would normally be required for a diagnosis of addiction, and that it affects a large proportion of young adults who would not otherwise qualify as having a medically diagnosed eating disorder.
Overall, the students in this study were very similar to each other in terms of age, ethnicity, and body mass index, with most being in the ‘normal weight’ range for their height. Yet body image and dieting behaviour were very different between the three groups, and three in five clinical ‘food addicts’ were dieting, compared with one in five self-perceived ‘food addicts’, and only one in ten ‘non-addicts’. It is not clear why young people with ostensibly similar physical characteristics should differ in this way, and whether dieting behaviour precedes symptoms of 'food addiction’ or whether ‘food addicted’ individuals feel the need to diet to maintain their weight despite their cravings.
Self-perceived ‘food addiction’, whilst not qualifying as a clinical addiction, nevertheless seems to represent a large and previously unrecognised category of problem eating in the population. In our future work, we would like to explore whether addressing people’s beliefs about their bodies and improving their self-esteem might be a useful way to help them normalise their relationship with food and cure them of their ‘addictions’ once and for all.
Angela Meadows, Doctoral Researcher in the School of Psychology at the University of Birmingham.