Studies reporting the indirect effects of the COVID-19 crisis on nutrition and lifestyle in children are still scarce and were mainly carried out in high- or middle-income countries. An Italian survey conducted during 3 weeks of home confinement included 41 obese children aged 6–18 years [7]. It showed that intakes of potato chip, red meat and sugary drinks increased significantly during the lockdown (P-value range: 0.005 to < 0.001), while time spent in sports activities decreased by 2.3 (±4.6 SD) hours/week (P = 0.003) and screen time increased by 4.8 (±2.4 SD) hours/day (P < 0.001). Similarly, an international survey conducted in Italy, Spain, Chile, Colombia and Brazil among 820 adolescents reported a significant increase in the consumption of fried and sweet foods during COVID-19 restrictions with greater adherence to unhealthy food among adolescents whose mothers had low education [8]. Another Italian survey conducted during confinement included 3533 respondents aged between 12 and 86 years [9]. The population group aged 12–17 years reported an increase in junk food consumption and a lower adherence to the Mediterranean diet when compared to the group aged 18–30. In the United States, 1048 families enrolled in a school-based nutrition program responded to an electronic survey covering 4 geographic areas [10]. Overall, 93.5% of respondents reported being food insecure in April 2020 compared to 71.5% in fall 2019, and 41.4% reported a decrease in fruit and vegetable intake because of COVID-19 [10].
On the other hand, an online survey conducted in Poland in May 2020 among 2448 adolescents aged 15–20 years suggested that the pandemic may have brought positive changes promoting the uptake of a better diet [11]. It revealed that health and weight control were the main determinants of food choices of adolescents during the COVID-19 pandemic compared to before the pandemic, outstripping the sensory appeal of food and mood (p < 0.0001). One of the largest studies conducted on this topic comes from the NutriNet-Sante cohort which surveyed a population of 37.252 French adults and households between March and May 2020 [12]. The findings suggest that the lockdown led, in a substantial part of the population, to unhealthy nutritional and lifestyle behaviors: decreased physical activity (53%), increased sedentary time (63%), increased snacking (21%), decreased consumption of fresh foods (27%), increased consumption of sweets (22%), eating in response to boredom (18%) or anxiety (10%) with a weight gain of 1.8 kg on average for 35% of the respondents. However, the lockdown also created an opportunity for some people to improve their nutritional behaviors including increased home-made cooking (40%) and increased physical activity (19%). Interestingly, persons with less favorable nutritional trends were more likely to have lower incomes, to be overweight or obese, to have anxiety or depressive symptoms and to have children under 18 years at home [12].
At our University Hospital in Lausanne Switzerland, we conducted a survey in the emergency department in August 2020. Parents of stable patients received a questionnaire on eating and lifestyle habits during but also 3 months after the semi-confinement carried out in Switzerland between mid-March and end of April 2020. The questionnaire was filled out by 128 families, including a non-negligible proportion of migrants. The sample was equally distributed between genders and one third of children was younger than 4 years. During confinement, 40% of children reported eating and snacking more than usual. Time spent on screens increased for 75% of children and up to 100% for adolescents. More alarming was the percentage of children under the age of 4 watching screens: 73% of boys and 41% of girls. As for physical activity, the proportion of children spending less than 2 h of light physical activity per day doubled during confinement. One third of parents estimate that their child gained excess weight during this period, but their previous growth parameters were not available for an objective comparison. The survey also revealed that a significant proportion of children (58%) suffered changes in their behavior: sleep disturbances, stress and anxiety. The most concerning finding is the persistence of the majority of these bad habits more than 3 months after the lockdown, for 20% of children regarding snacking and for 37% of them regarding screen time.