Table 1 Investigated questions on baseline dietary and behavioral habits, and willingness to change dietary and behavioral habits after experiencing the outbreak of COVID-19

Baseline dietary habits

 Salt intake: “Before COVID-19, What about your dietary intake of salt?”

 Intake frequency of fresh vegetables: “Before COVID-19, how often did you normally eat fresh vegetables?”

 Intake frequency of fresh fruits: “Before COVID-19, how often did you normally eat fresh fruits?”

 Intake frequency of meat, eggs, milk, or dairy products: “Before COVID-19, how often did you normally eat meat, eggs, milk, or dairy products?”

 Intake frequency of fried foods: “Before COVID-19, how often did you normally eat fried foods?”

 Intake frequency of sugary foods: “Before COVID-19, how often did you normally eat sugar or sugary foods (including sugary drinks, desserts, biscuits, sweets, fruit products, dairy desserts, etc.)?”

 Intake frequency of pickled vegetables: “Before COVID-19, how often did you normally eat pickled vegetables?”

 Intake frequency of processed meat: “Before COVID-19, how often did you normally eat processed meat?”

Baseline behavioral habits

 Smoking cigarettes per day: “Before COVID-19, how many cigarettes did you normally smoke per day?”

 Frequency of alcohol consumption: “Before COVID-19, how often did you normally drink alcohol?”

 Sleep duration (including lunch break): “Before COVID-19, how long often did you sleep (including lunch break)?”

 Physical exercise time per week: “Before COVID-19, how long often did your physical exercise per week?”

Willingness to change dietary habits

 Salt: “Do you plan or are you changing salt intake after experiencing the outbreak of COVID-19?”

 Fresh vegetables: “Do you plan or are you changing the intake frequency of fresh vegetables after experiencing the outbreak of COVID-19?”

 Fresh fruits: “Do you plan or are you changing the intake frequency of fresh fruits after experiencing the outbreak of COVID-19?”

 Meat, eggs, milk, or dairy products: “Do you plan or are you changing the intake frequency of meat, eggs, milk, or dairy products after experiencing the outbreak of COVID-19?”

 Fried foods: “Do you plan or are you changing the intake frequency of fried foods after experiencing the outbreak of COVID-19?”

 Sugary foods: “Do you plan or are you changing the intake frequency of sugary foods after experiencing the outbreak of COVID-19?”

 Pickled vegetables: “Do you plan or are you changing the intake frequency of pickled vegetables after experiencing the outbreak of COVID-19?”

 Processed meat: “Do you plan or are you changing the intake frequency of processed meat after experiencing the outbreak of COVID-19?”

Willingness to change behavioral habits

 Smoking: “Do you plan or are you changing the number of smoking cigarettes per day after experiencing the outbreak of COVID-19?”

 Alcohol consumption: “Do you plan or are you changing the frequency of alcohol consumption after experiencing the outbreak of COVID-19?”

 Sleep: “Do you plan or are you changing sleep duration after experiencing the outbreak of COVID-19?”

 Physical exercise: “Do you plan or are you changing physical exercise time after experiencing the outbreak of COVID-19?”