The behavioral factors related to eating, including the eating speed is one of the increasing concerns to restrict energy intake in which it became a hallmark of many weight control programs. The importance of altering eating behaviors in health promotion is broadly recognized. Eating behaviors have an imperative role in preventing diseases such as diabetes, obesity, and cardiovascular disease (Ferriday, Bosworth, et al. 2015). Some epidemiological surveys have indicated positive relations between eating rapidly and metabolic syndrome (Hsieh, Muto, et al. 2011) and obesity (Ohkuma, Fujii, et al. 2013). Studies showed that eating too speedy is associated with overeating (Zhu, Hsu, et al. 2013). There is a relationship between eating speed and satiety (Privitera, Cooper, et al. 2012, Ferriday, Bosworth, et al. 2015). The eating speed affects satiety and food intake so a slower eating speed is associated with increased satiety and decreased food intake. Two hypotheses are proposed: the first demonstrates that slower eating gives time to start the physiological satiety signals and the second hypothesis suggests that slower eating enhances and prolongs satisfying eating so declines feelings of hunger (Privitera, Cooper, et al. 2012). However, data to support these hypotheses have been inconsistent. A systematic review of controlled trial studies has revealed that quicker eating is associated with more energy intake (Robinson, Almiron-Roig, et al. 2014), and higher body mass index (BMI) (Almiron-Roig, Tsiountsioura, et al. 2015) is clinically important. Recently, the effects of some factors such as bite-size, food viscosity, food service form, and eating method on the eating speed have been investigated. In one study by E Almiron-Roig, it was reported that larger portion size leads to bigger bite-size and quicker eating speed (de Graaf 2011, E Almiron-Roig, Tsiountsioura, et al. 2015). In another study, Zhu found that the increased food viscosity resulted in a reduced eating speed, decreased postprandial appetite, and appetite to eat (Zhu, Hsu, et al. 2013). Suh in their study showed that the eating speed was decreased when the mixed form of a meal was served and in another study, Sun showed that the eating speed and chewing time changed with diverse feeding tools (chopsticks, fingers, and spoon) (Sun, Ranawana, et al. 2015, Suh and Jung 2016), However, studies about the impacts of psychological factors in this field are rare. One of these possible factors is personality traits.
Personality traits are described as individual patterns of feeling, thinking, and acting (Scoffier-Mériaux, Falzon, et al. 2015). The behaviors of persons are affected by their personality. The big five-model of traits is mostly used to determine personality traits. This model classifies personality traits into five categories i.e. conscientiousness, extraversion, neuroticism, agreeableness, and openness to experience (Feizi, Keshteli, et al. 2014). Conscientiousness (C) is an attempt to organize purpose and insistence to achieve goals. Extraversion (E) is the tendency toward vigorous and social activity. Neuroticism (N) is attending to experience negative actions. Agreeableness (A) is a tendency toward friendliness and sociability. Openness (O) is the liking in experiencing novel things, opinions, and individuals (Roohafza, Feizi, et al. 2016). Personality traits are associated with several health outcomes (Raynor and Levine 2009). Recent studies indicated that personality traits affect eating styles, food choices, and eating disorders (Mottus, Realo et al. 2012, Keller and Siegrist 2015). One study by Mottus et al. revealed a significant relationship between personality traits and eating habits (Mõttus, McNeill, et al. 2013).
The aforementioned evidence provides a good base for hypothesizing that the eating speed may also be related to people’s personality traits, but to our knowledge, the relation between personality and eating speed is not investigated, so this study aimed to assess the relationship between personality traits and eating speed.