**2. Lifestyle**

Research has shown that a healthy lifestyle has a positive influence on both physical and mental health. A longitudinal study with German (n = 2.991) and Chinese students (n = 12.405) shows that in people with a healthier lifestyle psychological well-being is higher and mental health problems are fewer compared to groups with a less healthy lifestyle. Lifestyle factors such as lower body mass index, high frequency of physical and mental activities, non-smoking, a non-vegetarian diet, and a more regular social rhythm were positive predictors of mental health [13].

Keeping companion animals is part of a lifestyle. Most companion animals are omnivores that also eat meat. In a study with 3.673 pet owners, the number of vegetarians (6.2%) and vegans (5.8%) was higher than in the general population. Only a minor part of these owners (1.6%) fed their animals a plant-based diet. All pet owners feeding their pets a plant-based diet were vegans, with the exception of one vegetarian dog owner [14].

The country with the highest percentage of vegetarians is India, with about 40% of the Asian Indians being vegetarian. A study on this population shows that a vegetarian diet does not necessarily imply a healthy lifestyle. Nowadays, people eat more refined and processed foods, fried foods and refined carbohydrates instead of whole plant foods than before. In recent years, the number of Asian Indians who needed bariatric surgery was higher in female vegetarians than in non-vegetarian females because of a higher incidence of morbid obesity [15].

Similar results were found in an Iranian population, where a plant-based diet with wholesome plants (e.g. whole grains, fruits, vegetables, nuts, legumes, vegetable oils) was associated with fewer psychological disorders and a diet with unhealthy plant foods was associated with increased risks of obesity and depression. A plant-based diet, rich in wholesome foods was inversely associated with psychological disorders. Furthermore, unhealthy plant foods (e.g. fruit juices, sweetened beverages, refined grains, potatoes, sweets/desserts) were associated with increased risks of obesity as well as depression [16].

**21**

extraversion [24].

*Vegetarian or Vegan Diet: Stimulating or at Risk to Mental Health?*

Not everybody chooses a plant-based diet. Socio-demographic factors are different for meat eaters and vegetarians/vegans. In a French cross-sectional study based on self-reports and including 93.823 participants it was shown that vegetarians' educational levels were higher and vegans' were lower than those of meat eaters and vegans had a lower educational level than meat eaters. Vegetarians were more likely to be young women, and self-employed than meat eaters. Their diets were the most balanced in terms of nutrients. Vegetarians were more strict at following the French dietary guidelines than non-vegetarians, and also had fewer nutritional deficiencies in antioxidant vitamins (such as vitamin E) compared to meat eaters. Vegans, on the other hand, showed more deficiencies in some nutrients (especially vitaminB12) compared to meat eaters [17]. Also, in a study from the US found that vegetarians and vegans who had chosen this diet for health reasons were more likely to be highly educated, female and physically active [18]. Not everyone opting for a vegetarian/vegan diet continues their plant-based diet. A remarkable finding is that conservative political ideological views are a

Semi-vegetarians' and flexitarians' motives differ from those of vegans, lactoovo-vegetarians, and omnivores. Semi-vegetarians and flexitarians are more vulnerable to engaging in maladaptive eating habits than those engaging in more extreme

In addition to reasons mentioned and unknown reasons, personality characteristics can also play a role. Individual differences in personality may play a significant role in explaining individual food choices. In this context, the Five-factor model of personality [22] has often been investigated. This model describes a structure of personality characteristics containing 5 factors: neuroticism, extraversion, open-

Neuroticism, conscientiousness and extraversion have a significant direct influence on eating habits and food choices. Vegetarians and semi-vegetarians were

A high degree of openness to new experiences would seem to be a powerful predictor of vegetarian food choices [20, 23, 24]. On the other hand, associations between meat consumption and openness to new experiences were also found [25]. This appears to vary depending on the type of meat consumed [26]. The associations with respect to conscientiousness and meat consumption vary, with positive and negative relationships having been reported in different studies [26, 27]. Extraversion has been linked to higher meat consumption [27]; a lower degree of extraversion has been related to a lower frequency of animal product intake [28]. Vegetarians and semi-vegetarians appear to be more neurotic and depressed than omnivores [23]. Neuroticism also influences the intake of sweets and savoury foods due to emotional and external eating [25]. Studies exploring associations between agreeableness and dietary style have shown mixed results [23, 25, 27]. In a large study (n = 13.892) a comparison was made between three eating styles: *carbohydratebased food* (e.g., bread, pasta, snacks), *meat* (e.g. red meat, poultry), and *plant-based* 

These three dietary styles showed different associations with personality. Eating plant-based food and fish was positively associated with openness, conscientiousness, and emotional stability while meat consumption was negatively associated with openness and emotional stability, and positively associated with

In a study about the relation between the dark triad of personality (Machiavellianism, narcissism and psychopathy) and diet it was found that

forms of meat restriction. These findings hold for all ages and genders [21].

ness to experience, agreeableness and conscientiousness.

found to be more neurotic compared to omnivores [23].

*food and fish* (e.g. vegetables, fruits, legumes, fish).

*DOI: http://dx.doi.org/10.5772/intechopen.94371*

predictor of a return to eating meat [19, 20].

**3. Personality characteristics**
