Until this moment, no research has been found that has assessed adherence to online nutritional monitoring by adults with Diabetes Mellitus Type 1 (T1DM) during the pandemic. This article aims to analyze the association between eating habits and adherence to nutritional online care by adults with T1DM during social distancing because of the COVID-19 pandemic in Brazil. A cross-sectional study was carried out in July 2020. An online form was used to collect sociodemographic data, financial status, eating habits, carrying out online nutritional monitoring, and adherence to social distancing. Pearson’s chi-squared test was performed with adjusted residual analysis and binomial logistic regression analysis (p < 0.05). Out of the 472 adults, only 8.9% had consulted with a nutritionist. Doing nutritional monitoring online during social distancing was associated with a reduction in the consumption of ultra-processed foods (p = 0.021), eating more servings of fruit (p = 0.036), and doing carbohydrate counting (CC) more frequently (p = 0.000). Doing nutritional monitoring online increased adherence to carbohydrate counting by 2.57 times and increased the consumption of fruits by 0.423 times. Therefore, nutritional monitoring, even if performed remotely, can influence the acquisition and maintenance of healthier eating habits, in addition to assisting adherence to the practice of CC.