Disordered eating and the increasing prevalence of obesity in Western societies are major public health concerns [1, 2]. These conditions are strongly related to gender [3–5], but the reasons underlying the observed gender differences are poorly understood. Disordered eating, defined as harmful and often ineffective eating behaviours used with the aim of losing weight or changing one’s appearance , was reported by nearly a third of the Swiss population , and has been shown to predict weight gain and to be a risk factor for the onset of obesity  and eating disorders . Dissatisfaction with one’s own body weight is an attitudinal component of body image , which predicts dieting behaviour , stress, depression, bulimic symptoms and low self-esteem . Weight dissatisfaction, with prevalence rates ranging from a third to more than one half of the population [7, 13] was associated with disordered eating in cross-sectional studies  and identified as a risk factor for the development of disordered eating in longitudinal studies [15, 16].
Gender is known to play an important role in relation to weight dissatisfaction and disordered eating behaviours [3, 17]. Although the prevalence of obesity in adulthood was higher in men, women showed greater dissatisfaction with their weight than men [7, 13, 18], dieted more frequently, and demonstrated more disordered eating than men, particularly in younger adulthood [18, 19]. This has also been found in the Swiss Health Survey 2007 . Research about these problems has often focused on young women [4, 20, 21]. Weight dissatisfaction seems to be prevalent across the entire life span in women. It was even found to be one of the most important body image concerns in women aged 61–92 years . Body dissatisfaction has been shown to be stable in adult women [21, 23]. In contrast, in men the desire to lose weight has been found to increase as they get older .
Previous studies have reported inconsistent results relating to gender differences associated with the relationship between BMI and weight dissatisfaction: Tiggemann  has indicated a weaker association between BMI and body dissatisfaction in women compared to men, while Millstein et al.  suggested similar associations for both genders. It has been found that in both genders a higher BMI was associated with the engagement in dieting behaviours . In boys, weight perception and dieting have been significantly associated with BMI  and a higher BMI was associated with greater body dissatisfaction and a greater likelihood of changing eating habits [3, 25]. Women often wish to lose weight, whereas men want a body that is either larger and more muscular, or thinner [4, 25, 26]. However, the extent to which BMI is related to weight dissatisfaction in adult men has not been fully investigated [4, 20] and the gender difference in this association is not fully clear.
The prevalence of dieting is higher in women than in men [19, 27, 28]. Dieting was even found to be prevalent in older age groups . In a population-based Swiss study 42 % of the 30–74 year-old women had dieted in the last 5 years . Of those, 67 % had a normal weight. Of the women older than 67 years of age, 31 % had dieted, although 62 % of them had a normal weight. In a study by Tiggemann and Lynch  disordered eating in women was found to decline with increasing age.
Other eating behaviours, such as binge eating, appear to have similar prevalence rates in men and women [30, 31]. In the study by Lavender et al.  the results of different studies were compared and showed that 25 % of the men reported binge episodes, 24 % dietary restraint and 3.2 % self-induced vomiting . Women had comparable prevalence rates [30, 32]. Other studies have found higher binge eating rates in women than in men [28, 33].
It has been suggested that physical activity might be a protective factor in the development of disordered eating behaviours, particularly in girls [27, 34]. Results of a meta-analysis showed that the risk of disordered eating was reduced in non-elite athletes compared to controls . However, under certain circumstances, depending on the type of exercise and the reason for exercise, sports participation can also be a risk factor for disordered eating [34–36]. In a representative sample of Canadian men, daily physical activity was a risk factor for eating disorders .
A relationship between gender, weight dissatisfaction and disordered eating has been indicated [3, 38]. However, results from population-based studies investigating gender differences in specific disordered eating behaviours and gender specific risk factors are still needed . Furthermore, the understanding of weight dissatisfaction and disordered eating across the adult life span in men and women is still limited .
The aim of the current study was to examine the prevalence rates of both, weight dissatisfaction and disordered eating (such as dieting, binge eating and irregular eating) in a large representative sample of Swiss adults. Furthermore, the association of weight dissatisfaction and disordered eating with sociodemographic factors (education, age, nationality), and with weight category, smoking and physical activity in men and women was examined.