Introduction

During the first wave of the COVID-19 pandemic, confinement and social distancing were recommended by the World Health Organization [1], impacting over daily lifestyles, including eating habits [2,3]. Recent studies have shown a significant increase in the consumption of bakery products, instant meals, and fast-food eating habits [4] and alcohol during the confinement [5]

The forced and prolonged stay at home, the stress resulting from the pandemic [6,7,8], and the complex socioeconomic situation that increased unemployment figures and food costs, may decrease the acquisition of healthy foods [2,9]. In Chile, the confinement began on March 18th, 2020, and ended on October 1st, 2021. It was carried out dynamically throughout the country, where regions and communes went on and off quarantine depending on local health indicators. In this context, changes in food consumption were influenced by production, distribution, and marketing restrictions, as well as purchasing fresh foods from local markets. This situation greatly affected most the vulnerable sectors because they were the ones who spent the longest time in confinement, had limited permissions to go grocery shopping [10], noticed a food price increase, and had difficulty storing products [9]. The COVID-19 Social Survey indicates that from June to August 2020, 47% of the population of the Metropolitan Region was affected by their income, and 18% presented food insecurity [11]. Before the pandemic in Chile, there was already evidence of inequality and inequity in food consumption according to the socioeconomic and educational level [12]. Furthermore, culturally, the nutrition in the Chilean family group has been characterized by high consumption of ultra-processed foods and sugary beverages, leading second place in Latin America and seventh when compared with 80 countries in annual per capita sales of ultra-processed food and beverages [13].

The ultra-processed products are usually fried and rich in sugars and saturated fats [14], and are associated with an increased risk of developing overweight, obesity [15,16,17,18,19], and chronic non-communicable diseases (NCD), all of which are major contributors to death and disability in the world. In turn, these are the main risk factors for complications in people with COVID-19 [18].

This study aimed to evaluate factors associated with increased consumption of sugary beverages and fast food among adults in Chile during the First COVID-19 lockdown. In order to achieve this, three specific objectives were outlined: (1) to characterize sociodemographic and socioeconomic variables among participants aged 18 years or older in the Metropolitan Region; (2) to estimate the prevalence of sugary beverage and fast food consumption during the initial phase of the lockdown; and (3) to identify socioeconomic factors linked to such consumption patterns, while adjusting for age and sex.

Methods

A cross-sectional study was conducted among adults aged 18 years and older residing in Chile during the COVID-19 lockdown period. Data were via a self-administered online survey administered between May 17 and August 17, 2020. The majority of respondents (98.3%, n = 6971) completed the survey prior to the implementation of the "Step by Step" reopening plan. Data collection and management were carried out using SurveyMonkey®, an electronic data capture platform hosted by the Fundació Institut Universitari per a la Recerca a l’Atenció Primària de Salut Jordi Gol i Gurina (Barcelona, Spain).

Sampling

Participant recruitment was conducted through online platforms and social media using convenience and snowball sampling techniques. The online survey was developed by a multidisciplinary research team based in Spain. A pilot study was conducted to assess the clarity and comprehensibility of the instrument, and subsequent modifications were made to ensure its cultural and linguistic appropriateness for the Chilean context. The pilot included academics, administrative staff, and undergraduate and postgraduate students. At the beginning of the survey, participants were informed of the study’s objectives and the estimated completion time, which was approximately 10 minutes, including the reading and electronic signing of the informed consent form.

Variables

The dependent variables were the self-perception of consumption of fast food (like burgers, fries, pizza, etc.) and sugary beverages (known as sugar-sweetened beverages), each with four response options on a Likert scale (I don’t consume, I have increased consumption, I have maintained the same consumption, and I have reduced consumption), which were then dichotomized into increased consumption (yes and no).

The independent variables included sociodemographic and socioeconomic factors such as age, sex, type of health insurance (the Chilean health system consists of a mixed model, with a public system called FONASA and a private system called ISAPRE), educational level, pre-pandemic employment status, self-reported change in employment status, and region of residence (Table 1).

Statistical analysis

Variables were described by calculating frequencies and percentages. The association between each independent variable with each dependent variable was evaluated using the Chi-Square test. Multivariate logistic regression models were fitted to assess the association between potential factors associated with increased fast-food consumption and sugary beverages. Since the odds ratio overestimates the association’s size, log-binomial models were also fitted to obtain prevalence ratios and 95% confidence intervals.

Statistically significant differences were considered when the p-value was p < 0.05. All analyses were performed using Stata 18 (Statistical Software Stata: Release 18 College Station, TX: StataCorp LP).

Ethics approval

This study was approved by the Research Ethics Committee on Human Beings (CEISH) of the School of Medicine-University of Chile (Project: N° 053-2020, act: N°017, date 05-12-2020) with the authorization to obtain online informed consent before the start of the survey.

Results

6971 answered the online survey, of which 63.5% were females, 74% were under the age of 50, and only 4.9% were foreign. 51.4% had private health insurance (ISAPRE), and 69.9% had higher education. The regions with the greatest participation were the Metropolitan region 67.2%, the Valparaíso region 8.7%, and the Biobío region 4.3%. Regarding the employment situation, 28.3% indicated it worsened and 15.4% indicated an increase in the consumption of sugary beverages, and 19.6% indicated an increase in fast food (Table 1).

Table 2 shows the prevalence and crude association of the sociodemographic variables and socioeconomic conditions according to the increased consumption of sugary beverages. The highest prevalence is observed in those under the age of 50 (p < 0.001), in those whose employment situation worsened by “little” or “a lot” (p < 0.004), and in those with a secondary or higher level of education (p < 0.017). Statistically significant differences were not observed according to sex, health insurance, and region of residence.

Regarding the increased consumption of fast food, the prevalence and its crude association with the sociodemographic variables and socioeconomic characteristics are shown in Table 3. The highest prevalence of increased consumption is observed in females (20.9%, p < 0.001), and in those under the age of 40 (52.8%, p < 0.001). Also, differences were found between geographical areas, where the Biobío region (14.1%) presented an increased consumption significantly lower than the other regions. Variables such as health insurance, employment situation, and level of education did not show statistical significance (Table 3).

tables 4 and 5 describe the fitted multivariable models for increased consumption of sugary beverages and fast-food consumption, using logistic and log-binomial regression models.

The variables that showed an association with increased consumption of sugary beverages were the same as those observed in the bivariate analysis, except for the level of education (Table 2). A decrease was observed in the prevalence of consumption as age increased between the ages of 40 to 49 (prevalence ratio (PR): 0.74; 95% confidence interval (CI): 0.63 to 0.89) and 50 and over (PR: 0.41; 95% CI: 0.33 to 0.51). Concerning the employment situation, it was observed that in those whose employment situation worsened by a little, the prevalence was higher ( 26%, p < 0.001) (Table 4).

Table 5 shows the results of the multivariable-fitted logistic and log-binomial models. The statistical significance variables in both models are similar, with a slight difference in the magnitude of the effect measures in odds ratio (OR) and PR. For example, the prevalence of increased fast-food consumption was 18% higher in females than males (p < 0.002). Regarding age, there was a gradient decrease in consumption as age increased, observing a 39% decrease between the ages of 40 to 49 years old (PR: 0.67; 95% CI: 0.58 to 0.78; p < 0.001) and 64% in those aged 50 and over (PR: 0.36; 95% CI: 0.30 to 0.44; p < 0.001). Regarding the comparison between geographical areas, the Biobío region presented a lower risk than the other regions but without showing statistically significant differences with the Metropolitan Region (Table 5).

Discussion

The findings of this study during the first stage of confinement show a 15.4% and 19.6% increase in the consumption of sugary beverages and fast food, respectively. This increased consumption is greater in females, decreases with age, and varies depending on the region of residence in Chile.

The increased consumption of sugary beverages and fast food during confinement has been previously described in international studies [2,3,19,20]. These studies, which mostly applied online questionnaires to adults, have reported increased consumption of fast food, frozen food, snacks, sweets, and sugary beverages, among other ultra-processed foods.

We found a higher prevalence of increased consumption of sugary beverages and fast food in females, this difference was only statistically significant for fast food. This finding aligns with several studies [21,22,23,24]. One of the studies conducted in the Netherlands showed that females had more difficulties making healthy decisions (OR: 2.07; 95% CI: 1.33 to 3.23) and opted to order fast food (OR: 2.38; 95% CI: 1.15 to 4.93) [20]. Another study in 16 countries revealed that females increased their consumption of sweet foods and ultra-processed foods, not sugary beverages [23]. Another study indicated that women consumed more sugary beverages than men during confinement [24]. In contrast to our results, a study carried out during confinement in Portugal reported a significant increase in the consumption of fast food and sugary beverages among males than in females [25]. It should be noted that the reported results in the articles are not uniform by gender. In addition, the data in this study were self-reported, which may limit the representativeness of the estimated prevalences.

Some studies have attributed the increased consumption of sugary drinks and fast food to the psychological impact of confinement, where anxiety, stress, and depression are associated with increased consumption [2,21,22,23,24,25,26]. In Chile, the COVID-19 Social Survey shows gender inequality by indicating that 26% of women presented severe symptoms of anxiety and depression [11]. This may also be due to the burden of domestic work, caring for relatives and children, and the family’s economic situation. In addition, remote working and limited social support from extended family and friends have made it difficult to buy and prepare healthy food, leading to increased fast-food consumption [23,27].

Regarding age, this study’s results are similar with other studies [2,3,12,28], where the consumption of sugary beverages and fast food were higher in adolescents and young adults compared to older adults. Previous studies carried out in Chile reveal similar results, where people under the age of 49 consumed sugary and soft beverages, candy, and sweet foods more than older adults [12]. Also, the consumption of fast food may be generational as youth are the ones who consume this type of food and purchase fast food through different virtual platforms for home deliveries. On the other hand, consumption of unhealthy foods has been attributed to group influence amongst adolescents and young adults [28]. Another study showed increased teleworking in young adults during confinement, which may have influenced the preference for ready-to-eat foods due to the lack of time to prepare fresh foods at home [29]. Lastly, increased exposure to sugary beverages and fast-food advertisements had a greater influence on adolescents and young adults due to the greater use of screens [21,30,31].

Regarding the employment situation, we found that consumption of sugary beverages increased with worsened employment situation , but not in fast food consumption. The lower cost of sugary drinks could influence this difference compared to fast food. In Chile, people affected by their employment situation had a greater consumption of fast food and sugary beverages since they carried out informal and manual jobs, mainly in sectors such as commerce, tourism, or construction. The loss of employment and decreased income [11,32] are associated with food insecurity [33], given that 68% reduced their expenses (on food, health, education, and electric heater). In Mexico, a study done during the COVID-19 confinement shows that households with reduced spending and food insecurity had a greater likelihood of a worsening in their diet, including an increase in sugary beverages [34]. On the other hand, in Chile, another study showed an increase in healthy food consumption during the pandemic and a decrease in the consumption of ultra-processed foods and sugary beverages, contrary to the data analyzed in our study [35]. Moreover, a study in Spain showed that people with accelssibility and financial stability had an easier time consuming healthy food and improved their diet [36].

The consumption pattern was relatively similar throughout different regions of the country, although a smaller increase in the prevalence of consumption of fast food was evident in the Biobío region, possibly attributed to the environment, socioeconomic level, availability, and access.

The change in income, female, age, and region of residence, and their relationship to the consumption of sugary drinks and fast food during the COVID-19 pandemic was possibly also influenced by changes in food systems at the level of food production, distribution, marketing, transport (packaging and storage), all of which directly influenced household food purchasing and provision [11].

Our results suggest a significant association between increased consumption of fast food and sugar-sweetened beverages during confinement, with changes in income, being female, and age. The fact that this study relies on self-reported data may introduce reporting bias. In addition, the fact that this research had a high participation of upper-middle-income individuals and was conducted during a period of heightened public health awareness due to the COVID-19 pandemic may influence the generalizability of the study results.