# Psychological Effects of Sweet Taste and Sweet Taste Preference
## 4 Sweet Taste Preference and Obesity  
The previous paragraphs outlined psychological effects of perceiving sweet taste on the activation of romantic or prosocial mindsets. Considering the global rise of overweight and obesity in adults and children, it seems of particular interest how sweet taste and the preference for sweet taste affect our eating behavior. The liking of sweet taste seems to be very powerful in many individuals. Some researchers argue that the preference of sweet taste is innate to all of us, and important, because it enables us to detect plants with available glucose [27]. Thus, sweet taste preferences seem to be logical from an evolutionary perspective because it offers a primary energy source. Others point out that sweet taste is preferred in comparison to bitter taste due to the latter's capacity to signal toxicity (whereas sweet taste provides information on potential beneficial effects of food) [28]. However, in  
Figure 2: In this study, participants tasted sweet or salty stimuli and subsequently tested with respect to their actual prosocial or altruistic intentions. Prosocial intentions were more frequent when experiencing a sweet taste relative to a salty taste before. Prosocial intentions were measured by asking participants to volunteer in another unrelated study (data taken from [18]). present times, detecting beneficial plants or avoiding toxic foods seems to be less important. In contrast, overweight and obesity has become one of the leading challenges in the western world. So how does the preference for sweet taste affect our eating behavior today? Based on the observation that the consumption of ultra-processed food is greater in individuals with overweight and obesity [29; 30], it is widely assumed that the liking of sweet foods may contribute to the development of obesity. However, research on the relationship between sweet taste preferences and obesity revealed mixed results and remains inconclusive [31]. For example, [PERSON] et al. investigated 150 children and found twice as many obese children in a group that preferred high sweet taste as compared to a group that preferred low sweet tastes [32]. In contrast, [PERSON] et al. examined the relationship between the liking of fatty or sugary foods, fruits and vegetables, and adiposity measures in 366 children aged 7-9 years. They found no association between obesity and liking of selected foods [33]. In a large sample including 24,776 French adults over five years [PERSON] et al. showed that unlike sweet and salt liking the preference for fat seems to be a major risk factor of obesity [34]. In a functional magnetic resonance imaging (fMRI) experiment [PERSON] et al. demonstrated that combined foods high in fat and carbohydrate are more valued than equicaloric foods and that this effect is reflected by recruitment of reward related brain areas such as the striatum. Remarkably, this effect was independent of the personal preferences of the participants [35]. Thus, the relationship between the preference for sweet taste and overweight and obesity seems to be more complex than assumed. The lack of converging results may be explained by different designs, types of sugary foods, and participants (e.g., children of different age or adults). Interestingly, it has been reported that taste perception in obesity is altered for sweet (and other) taste, which might explain a possible higher consumption of sweet foods in this group. For example, it has been shown that, in flies, a high-sugar diet results in decreased activity of neurons responsible for sweet taste perception, thereby leading to a reduced perception of sweet taste [36]. In addition, it has been shown in mice that chronic low-grade inflammation, due to obesity, diminishes the number of taste buds in gustatory tissues [37]. However, systematic studies in humans addressing the association between sweet taste threshold and obesity (e.g., BMI) reveal inconclusive results [31].