The analysis revealed some unhealthy diet-related behaviors common in the whole or part of the population. Dietary guidelines [9] recommend that children and adolescents should consume meals regularly, every 3–4 h, which sums up to 5 meals a day. Almost one-fifth of the population consumed fewer meals than recommended. On the other hand, most participants declared daily consumption of snacks, mostly sweets, and fruit. Consumption of fewer meals than recommended was slightly more common (approximately 40% of the population) in a study by Dolipska et al. [15] conducted in Śląskie, Opolskie, and Małopolskie voivodeships in Poland. Although we haven’t observed that the number of consumed meals per day was associated with the BMI of the participants, some other polish studies reported that consumption of fewer than 3 meals per day was more common in overweight and obese children [18, 21].
About one-fifth of the population didn’t consume breakfasts before attending school, which was similar to the percentage observed in Poland according to Health Behavior in School-Aged Children (HBSC) Study Report [7] and local studies [13, 15]. Consumption of breakfast is considered healthy behavior especially important in developmental age as it is associated with better cognitive function later in the day [25], better overall diet quality [26], and higher intake of fiber and micronutrients [27]. Skipping breakfast is also a behavior associated with an increased risk of excessive body mass in adolescents [28], and we also observed that skipping breakfast was more prevalent in children with overweight and obesity than in severely thin children. We also observed that skipping breakfast was more prevalent in the oldest age group (13–17) than in younger children, and this tendency was also reported in HBSC Study [7] and the local polish study conducted by Wojtyła-Buciora et al. [13] and Myszkowska-Ryciak et al. [21]. It is speculated that dietary habits are associated with school performance. According to Kim et al. [29], who conducted an analysis of more than 300,000 participants aged 12–18 years old, frequent consumption of breakfasts, fruit, vegetables, and milk was associated with better school performance, whereas higher consumption of soft drinks, instant dishes, fast food, and confectionery was negatively associated with school performance.
According to dietary guidelines for children and adolescents [9], vegetables and fruit (V&F) should be consumed as often as possible, preferably to every meal, considering however higher intake of vegetables than fruit. Increased consumption of V&F is associated with a decreased risk of cardiovascular diseases [30], type 2 diabetes [31], hypertension [32], and some types of cancer [33]. Only about one-fourth of our population consumed V&F several times a day as recommended. Although the percentage of participants, who consumed the recommended amount of V&F was low, it was, in fact, higher than observed in an HBSC study in Poland, where only 13.4% of 11–12-year-olds and 10.5% of 15–16-year-olds consumed vegetables several times a day [20]. Our observations of the frequency of consumption of V&F are in line with several local polish studies reporting the frequency of consumption of food groups in children and adolescents [17, 19]. On the other hand, Dolipska et al. [15] observed a higher frequency of consumption of V&F in primary school pupils (vegetables and fruit were consumed several times a day by 38% and 55% of participants, respectively). In the PRO GREENS study [34] conducted among 11-year-olds in 10 European countries, 23.5% of participants met recommendations of consumption of V&F, which is consistent with our findings. In the same study, 53.3% of participants did not even consume vegetables daily (in comparison 45.9% among 10–12-year-olds in our study). In our findings, the youngest children consumed V&F significantly more often than the oldest children, which is consistent with findings from the HBSC study [20]. In our study, children with obesity consumed significantly fewer vegetables than other children. Similarly, an inverse association between the consumption of vegetables and BMI was observed in the ISAAC study, which analyzed data from more than 200,000 adolescents from 36 countries [35]. Likewise, in a local polish study published by Zadka et al. [19] the frequency of V&F consumption decreased with increasing BMI of studied children and adolescents.
One-fifth of the population consumed milk and dairy products several times a day. According to dietary guidelines [9], children and adolescents should consume 3–4 servings of milk or other natural dairy products, like yogurt, buttermilk, kefir, or cheese daily, to deliver the recommended daily intake (RDI) of calcium. Milk and dairy are a rich source of high-quality protein, calcium, phosphorus, zinc, magnesium, vitamin D, and K, all of which play a crucial role in bone formation and skeletal development in childhood and adolescence [36]. Moreover, according to a meta-analysis recently conducted by Lu et al. [37], children with the highest intake of dairy were 38% less likely to have overweight and obesity in comparison with children characterized by the lowest intake. In a local polish study by Zadka et al. [19] more than half of mothers reported that children consumed dairy products once a day. In a study by Dolipska et al. [15] milk, natural yogurt, cottage cheese, and hard cheese were consumed several times a day by 20%, 11%, 7%, and 16% of primary school pupils, respectively. Conforming to our results, Stefańska et al. [14] reported that recommended amounts of milk were consumed only by 30% of 11–12-year-olds and 20% of 13–15-year-olds.
Processed meat products, like ham, sausages, paté occurred more often in the diet of participants on the daily basis (from 5 to 6 times a week to several times a day) than unprocessed poultry and red meat. Meat is an important source of high-quality protein, zinc, iron, and vitamins of the B-group. However, according to dietary guidelines, processed meat products should be avoided [9], due to higher than unprocessed meat content of saturated fatty acids, salt, nitrates, and polycyclic aromatic hydrocarbons. Increased intake of processed meat products is associated with an increased incidence of diabetes [37], cardiovascular diseases [38] and colorectal cancer [39].
Most participants consumed Coca-Cola and SSB 1–3 times a month; on the other hand, beverages like fruit juices and fruit drinks including flavored mineral waters were consumed more often. In our results, a minimal percentage of participants declared daily consumption of Coca-Cola and SSB, in contrast to results obtained by Szczepańska et al. [40], in which 37.8% of participants with normal body weight and 34.4% of overweight participants consumed SSB at least once a day. However, in the study by Szczepańska et al., there was no information on whether fruit drinks were also included in this percentage. Historically fruit juice was recommended for children as a replacement for some servings of whole fruit during the day. Up-to-date guidelines for infants, children, and adolescents by the American Academy of Pediatrics emphasize that fruit juice provides no advantage over whole fruit, but contains less fiber and more sugar, and therefore, it should be excluded from the diet of infants before 12 months of age and limited in the diet of children and teenagers between 7 and 18 years of age, as fruit juices play no essential role in a healthy, balanced diet [41]. Fruit drinks, on the other hand, are often mistakenly perceived by consumers as a product identical to fruit juice, when in fact they contain a minimum of 25% of fruit juice and often additionally added sugar, sweetener, or aroma [42]. Trying to follow nutritional guidelines, which recommend drinking 5–6 glasses of water per day [9], parents often provide children flavored mineral waters, which are more accepted by children due to their sweet taste. Flavored mineral waters are products more similar to SSB than natural water—they are waters with the addition of sugar, flavor, aroma, colorant, and preservative, but they are advertised as a replacement for natural mineral water, which can mislead consumers.
Almost one-third of the participants consumed sweets at least once a day and a similar percentage was observed in the HBSC study [20]. According to our results, sweets were among the most commonly consumed snacks between meals. In the study by Szczepańska et al. [40], 60.6% of participants with normal body weight and 54.2% of participants with overweight consumed sweets at least once a day. In more up-to-date studies [43], conducted in participants < 18 years old, daily consumption of sweets was reported in 30% of participants, which is consistent with our findings.
In our study, three-quarters of participants consumed fast-food dishes 1–3 times a month, the next 11.6% consumed such products 1–2 times a week. A higher prevalence of fast-food consumption was observed in the study by Mendyk et al. [43], where 61.1% of participants consumed fast-food products 1–3 times a month, whereas 33.6% consumed fast-food products at least once a week. On the contrary to the study by Mendyk et al. [43], in our study, individuals who completed the questionnaires were parents, which possibly, especially in the case of teenagers, could have led to some underestimation of unrecommended food groups. In a study by Dolipska et al. [15], 41% and 35% of participants reported consumption of fast-food dishes occasionally and several times a month, respectively.
In our study, children from the oldest age group (13–17 year-old) consumed breakfasts significantly less often and fewer meals per day than younger children. Moreover, they consumed additional meals outside home or school, salty snacks, Coca-Cola and SSB, fruit-flavored beverages, and fast-food dishes significantly more often than younger children and simultaneously they consumed V&F and fish significantly less often. To sum up, the oldest group of children, who received some autonomy regarding food choices, made more unhealthy diet-related choices.
There are some limitations to consider. The questionnaire used in this study was developed especially for this study, but it was not validated. Further study limitation regards parent-reporting of body weight and height of children and lack of actual measurements to confirm them. This is a common problem in studies conducted on large scale. On the other hand, according to Aasvee et al. [44], who performed validation of this method, underestimation of self-reported height and weight to anthropometric measurements in case of overweight was small and equaled 3.6%, and therefore, self-reported height and weight are still a method of choice in large survey studies. Our study presents results only from one region in Poland and they cannot be extrapolated directly to the whole Polish population. Having said that, the similarities between our results and observations from studies conducted in other regions in Poland indicate that our study accurately captures nutritional trends observed countrywide. One of the strengths to consider is a large population sample in comparison with other Polish studies.
