Date of Award


Degree Name

Doctor of Philosophy (College of Health Sciences)

Schools and Centres

Health Sciences

First Supervisor

Associate Professor Fiona Farringdon

Second Supervisor

Doctor Paola Chivers


Emerging adults are fast gaining recognition as an important target group for health promotion as previous research indicates very few are meeting dietary guidelines, often consuming foods that have increased saturated fats, sugar and sodium. These eating patterns place this group at higher risk of developing chronic illnesses such as obesity, diabetes, cardiovascular disease and cancer. Understanding how and why these eating patterns develop is important to help establish healthy eating behaviours and greater compliance to Australian Dietary Guidelines – Recommended Daily Serves (ADG-RDS) for emerging adults. International research has focused on eating habits, weight gain patterns and possible influences on behaviour however, there is limited research that explores these issues in an Australian context.

Consequently, this sequential, mix-methods study aimed to:

1. investigate the level of nutrition knowledge and identify the sources of nutrition information used by emerging adults

2. identify the nutrition information emerging adults want and how best to deliver these messages so they are perceived as relevant for this group

3. explore associations between correct ADG-RDS knowledge, influences on nutrition knowledge, eating behaviour and actual food group intake

4. explore the association between level of body satisfaction, eating attitudes and actual food group intake

The first phase of research involved qualitative data collection, from gender separated focus groups comprising four female groups (n=31) and four male groups (n=18) (Chapter Three). The focus groups interviews investigated the level of awareness of ADG-RDS, sources of nutrition knowledge, influences on eating behaviour and perception of current health promotion nutrition messages. The results indicated that participants identified a general awareness of ADG-RDS, however, confusion regarding serving sizes for different food groups was apparent. Social media was identified as both a source on nutrition knowledge and an influence on eating behaviour due to its impact on perceived body ideals. While there was acknowledgement that not all information was credible, there was also a strong tendency to follow the information regardless of the qualifications of the person providing the information, if they believed that it could provide the appearance related ideals they desired. Current health promotion messages were perceived as irrelevant because they focused on long term health consequences of poor diet. Consequently, participants indicated not following the dietary guidelines was a deliberate choice as health risks were not a priority for them. The major motivator for changing eating behaviour was identified as weight gain or appearance concerns.

The findings of the focus group interviews informed the development of a survey tool to assess level of knowledge regarding ADG-RDS and influences on nutrition knowledge, eating behaviour and food purchases. Food intake was measured by a Food Frequency Questionnaire (FFQ) that indicated consumption of individual food items over the previous four weeks. Body satisfaction was measured using Body Part Satisfaction Scale (BPSS-R) and eating attitudes using EAT-16. The survey was pilot tested among the target population (n=18) and was found to be valid and reliable. Subsequently, the second phase of the research quantitatively examined level of knowledge of ADG-RDS and food intake (FFQ) among university students (n=287) (Chapter Five). The influences on nutrition knowledge, eating behaviour and food purchase and their relationship to level of knowledge (ADG-RDS) and food intake (FFQ) were examined (Chapter Six). Body satisfaction (BPSS-R) and its relationship to food intake (FFQ), and influences on knowledge, eating behaviour and food purchases were also explored (Chapter Seven). Finally, associations between eating attitudes (EAT-16), food intake (FFQ), influences on knowledge, eating behaviour, food purchases and level of body satisfaction (BPSS-R) were examined (Chapter Eight).

Key findings indicated that knowledge of ADG-RDS for fruit and vegetables was consistent with the Go for 2 & 5 campaign message however, the majority chose the ‘don’t know’ option for RDS of all food groups confirming knowledge gaps. Correct knowledge was associated with fruit and vegetable consumption closer to ADG-RDS. Males were more likely to consume closer to ADG- RDS for meat, fish & eggs, dairy and grains than females (Chapter Five). School nutrition programs were identified as the largest influence on nutrition knowledge, but this was not associated with actual food intake. Parents were identified as the largest influencer on eating behaviour, and this was associated with higher intakes of meat, fish and eggs as well as baked goods and snacks (discretionary food). Half of all participants identified Instagram and Facebook as an influence on both nutrition knowledge and eating behaviour, while food purchases were influenced by price, taste and convenience (Chapter Six). Correct nutrition knowledge was not associated with higher levels of body satisfaction. There was a negative association between weight and other appearance concerns and body satisfaction, and eating behaviour influenced by social media was associated with lower levels of body satisfaction, particularly for females (Chapter Seven). Correct knowledge (ADG-RDS) was associated with higher EAT-16 scores indicating more risk of disordered eating. The influence of social media, weight and appearance concerns were all associated with higher EAT-16 scores, indicating a higher risk of disordered eating. Lower levels of body satisfaction were also associated with higher EAT-16 score for both males and females (Chapter Eight).

A novel finding that emerged from this Western Australian story was that emerging adults appear to make a deliberate choice not to follow ADG-RDS. While the findings confirm gaps in nutrition knowledge for this age group it also identified that correct knowledge was not translated to eating behaviours. An important finding was that the influences on nutrition knowledge were different from the influences on eating behaviour.

In conclusion, this research provides valuable insights for health promotion and health education in Western Australia. The study highlights the importance of understanding the influences on nutrition knowledge and eating behaviour of university students. The current focus on health consequence of poor diet is being ignored by this group as there is no sense of urgency. The outcomes from this research suggest that health promotion messages that focus on positive ‘do’ messages and more immediate benefits related to weight and appearance are more likely to resonant with Australian emerging adults.

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