Nutritional factors are strongly associated with the development, treatment, and prevention of chronic diseases such as hypertension, hyperlipidemia, diabetes mellitus, and cardiovascular diseases.1–4 As the incidence of chronic diseases has increased dramatically worldwide,5,6 it is urgent to investigate nutrient and food intakes and evaluate dietary patterns, which is beneficial for improving etiologic research on diet.

To assess dietary habits accurately, many epidemiological studies had been conducted. The food frequency questionnaire (FFQ) is a simple, convenient, and economic dietary assessment tool for a large study population. It includes a series of questions on the frequency and amount of certain food items, and it provides a general understanding of the subjects’ actual dietary food intakes.7 However, traditional, face-to-face, paper-based FFQs are expensive, time-consuming, and impossible to conduct in a short period,8 especially in China, which has a large population and vast territory. The internet is a fast, effective, widespread, and convenient tool used for daily communication, and various information and online courses can be found online. As people's health consciousness is growing, more individualized and professional evaluations of healthy diets are needed. Considering the aforementioned, we developed an internet-based diet and lifestyle questionnaire for Chinese (IDQC), which contains both a lifestyle survey and FFQ. Personal feedback on the subjects’ long-term or current lifestyle and diet is provided when the survey is completed. The IDQC will be a valuable tool for assessing individual health, and it may serve as a diet survey for experts and facilitate health policy making by the government.