In many developed countries, overweight and obesity have reached epidemic proportions [1–8]. One group at particular risk of weight gain and the development of obesity is young women[2, 9, 10]. In the US, for example, one study that tracked weight in a large population sample over a 10-year period found that major weight gain (increased body mass index (BMI) > 5 kg/m2) was twice as common in women (5.3%) as in men (2.3%) . A recent study of almost 9,000 women aged 18–23 years in Australia showed that 41% of the sample gained more than 5% of their BMI baseline over a four-year period (1996–2000) . This risk of weight gain and the development of obesity places young women at increased risk of a range of chronic medical conditions and diseases, such as hypertension, type-2 diabetes, cardiovascular disease, and certain cancers .
In an effort to reverse the current global epidemic of overweight and obesity, strategies to promote increased physical activity and to encourage healthy eating have been promoted in many countries [12–15]. In Australia, for instance, individuals are encouraged to consume diets that are low in fat, high in fibre and rich in fruits and vegetables, and to participate in at least 30-minutes of moderate-intensity activities at least five days/week . Despite such efforts, many young women do not meet the current physical activity recommendations  and their diets are less than optimal. For example, mean daily intakes of fruits and vegetables fall well below recommended levels  and 50% of young Australian women are consuming at least one takeaway meal per week, which is likely to be high in energy density . Poor compliance with dietary and physical activity guidelines is not unique to Australia [18–20]. In addition, recent work we have conducted suggests that many young women do not consider the kinds of lifestyle changes that are being recommended as feasible for them in the context of their daily lives . An understanding of the perceived barriers faced by young women in achieving healthy lifestyle changes is therefore important.
Most existing studies examining perceived barriers to physical activity and healthy eating have focused on the general population,[18, 22–25]. with few specifically considering the perceived barriers experienced by those at particular risk of weight gain, such as young women. However, the perceived barriers faced by young women are likely to differ from those faced by other groups, such as by men or older women. For example, a study in the USA showed that women more frequently report 'tiredness' and 'time' as significant perceived barriers to healthy habits than do men, and that this may be partly attributable to their domestic situation . In addition, young women are more likely than older women to experience particular life events (e.g. leaving family homes, starting work, entering a marital or de facto relationship, and becoming mothers) that may influence their physical activity and dietary habits [26, 27].
As well as perceiving different barriers to those faced by other groups in the population, the perceived barriers to increasing physical activity and improving diet that young women face may vary according to their social and personal circumstances. For example, having children is likely to impact on a women's ability to adopt healthy habits [21, 28, 29]. In addition, persons of lower socioeconomic status (SES) may have poorer access to parks, walking or jogging trails, and gym equipment than those of higher SES . Access to good quality, inexpensive healthy foods has also been reported to be more limited among persons of low SES; for instance, the cost of healthy foods has been reported to be greater for those living in deprived areas. [30, 31]. A number of studies have suggested that a lack of knowledge is a greater barrier to eating a healthy diet among those of lower education level [22, 23]. Being overweight can also be perceived as a significant barrier to physical activity . However, whether or not these factors are perceived as barriers to physical activity and healthy eating among young women is unknown.
In order to develop appropriate and effective obesity prevention strategies for young women it is important to understand the barriers they perceive in attempting to control their weight. The aim of this study was to examine perceptions of a range of personal, social and environmental barriers to physical activity and healthy eating, specifically related to weight maintenance, among young women, and how these vary by domestic situation, SES and overweight status.