###### Abstract
In the European Union, NCs mean \"any claim which states, suggests or implies that a food has particular beneficial nutritional properties due to: the energy (calorific value) it: provides, provides at a reduced or increased rate or does not provide or the nutrients or other substances it: contains, contains in reduced or increased proportions or does not contain\" [57]. According to various studies, NCs are commonly used both in Europe and North America [58; 59]. Nutrition Claims have been found to influence food perceptions and consumption behavior [60]. Generally, product utility increases with their presence on packaging [61]. It is also argued that the presence of NCs leads to higher food preferences [62]. In addition, in a study conducted among consumers with greater health problems, it was found that food is used more often if it contains a Nutrition Claim [63]. Indeed, these claims may help consumers identify healthier products [64; 65]. This means that consumers with a particular interest in health and a healthy diet will more likely be interested in information related to health [66], and thus, also claims, which translates into greater incentives to buy products bearing them [67]. Moreover, products with claims are more often chosen than identical products without them [68]. As a consequence, products containing claims are perceived healthier than those without [60]. As a result, it can be noted that the perceived healthiness of products containing claims may generally affect product assessment [62; 69; 70; 71]. However, some consumers may react differently to foods containing claims, especially when dealing with products assessed as healthy [62; 69] or unhealthy [45; 72]. [PERSON] [73] found that putting NCs on products considered as healthy may raise questions concerning the reason for supporting food which is already perceived as healthy. Placing an NC on unhealthy foods is preferred by some consumers [74], also being an excuse to reduce guilt [75] and justify the purchase [74]. While claims are important in guiding consumers towards food products [76], there are studies in which their effectiveness is questioned [69]. In addition, nutrition and advertising claims may cause negative effects, such as negative assessment of the healthfulness of food products, taste sensations and ultimately, reduced likelihood of purchasing products bearing NCs in the future [76]. Furthermore, some research argues whether the presence of NCs leads to greater food preferences [62] and perception [77]. Differences in the perception of claims and their impact on the products where they are placed may result from the fact that their very perception determines the assessment and purchase behavior of consumers [69; 70; 71]. Unfortunately, there is still no hard data to prove the actual impact of claims on different perceptions of products considered healthy or unhealthy [71]. It is also argued that there is a lack of information on whether front-of-pack labelling (FOP) is equally effective when Nutrition Claims appear or not [78]. Further research on this issue is required. However, nutrition claims still appear on food packaging very often. They also cover a variety of substances, such as salt, sugar, fat, fiber, vitamins, minerals, and proteins. For proteins, they are heterogeneous complex biomolecules representing one of the major macronutrients in the human diet [79]. They also regulate the activity of cells, muscle tissues and other metabolic processes. Therefore, it is crucial to use a diet rich in various proteins (plant and animal) because, due to their complementarity, they can provide all the essential amino acids necessary for the human body [80]. Amino acids are nutrients important for metabolism and the functioning of the whole organism, growth, development and health [80]. Due to the aforementioned discrepancies in research on NCs, it is not possible to show the clear influence of claims on customer perception.