| Summary: | Introduction: Many people believe that obesity is caused by an addiction to food. However, within the scientific community, there is ongoing debate surrounding the validity of the food addiction concept, and an operational definition of food addiction is yet to be established. An aim of the current thesis was to identify behaviours and cognitions which characterise addictive patterns of eating. To do so, Chapters 2-4 explored the characteristics of individuals who perceive themselves to be addicted to food (i.e. self-perceived food addicts). Based on these findings, Chapter 5 presents the development of a novel assessment tool for addictive-like eating. A second aim of the thesis was to explore food addiction beliefs from a psychosocial perspective. Specifically, Chapter 6 examined the consequences of food addiction beliefs on subsequent eating, and Chapter 7 explored whether the concept of food addiction may be used to alleviate eating-related guilt by implying that eating is beyond personal control. Methods: A combination of qualitative and experimental techniques were used to establish the cognitive and behavioural features of self- perceived food addiction. Chapter 2 consisted of a brief questionnaire which inductively explored beliefs about the manifestations of food addiction within the lay public. These findings were extended in Chapters 3 and 4 which experimentally tested whether self-perceived food addicts would demonstrate increased food reward and attention to high-fat food cues (using an eye-tracking paradigm), compared to those who do not perceive themselves as food addicts. Chapter 5 used exploratory and confirmatory factor analyses to develop a novel tool for the assessment of addictive eating (i.e. the Addictive Eating Behaviour Scale, AEBS). To address the second aim of the thesis, experimental techniques were used to manipulate participants’ beliefs about their levels of food addiction (Chapter 6) and feelings of eating-related guilt (Chapter 7). The effects of these beliefs on subsequent food intake (Chapter 6) and food addiction attributions (Chapter 7) were then examined. Results: Findings from Chapter 2 suggested that self-perceived food addicts find food particularly rewarding and may be particularly likely to overeat. Consistent with these findings, Chapter 3 found that self-perceived food addicts demonstrated increased desire-to-eat for a range of food, and consumed more of a high-fat food during ad libitum access, compared to self-perceived non-addicts. However, self- perceived food addicts did not show any increased attentional bias to food cues compared to non-addicts (Chapter 4). The AEBS (Chapter 5) consisted of two sub- scales: 1) unhealthy eating/low self-control, and 2) overeating/weight gain. This scale predicted variance in BMI beyond that accounted for by an existing measure of food addiction. With regard to the second aim of the thesis, Chapter 6 found that those who were told they had high levels of ‘food addiction’ consumed fewer calories compared to those who were told they had ‘low’ or ‘average’ food addiction. This was mediated by increased dietary concern and a reduction in the amount of time spent tasting high-fat foods. Finally, Chapter 7 found no effect of manipulating eating-related guilt on food addiction beliefs; however, across the whole sample, higher levels of guilt correlated with an increased tendency to attribute eating to the foods’ addictiveness. Conclusions:Overall, these findings suggest that self-perceived food addiction is characterised by several core behaviours, and that perceiving oneself to be a food addict may be helpful for those attempting to reduce their intake of certain foods, in the short-term at least. Future research should establish whether the AEBS captures food reward and calorie intake beyond that accounted for by established measures of aberrant dietary behaviour. Research should also examine the effects of food addiction beliefs on longer-term patterns of eating.
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