Food delivery applications (FDAs) shined during COVID-19 global lockdown restrictions. Consequently, lifestyle changes imposed a greater use of these applications over this period. These changes may strongly influence the nutritional health of individuals, particularly adult Saudi females. A cross-sectional study was performed to examine the influence of using FDAs during COVID-19 lockdown restrictions on attitude behaviours, including dietary habits and preferences among Saudi adult females. Participants voluntarily submitted their answers to a questionnaire administered via the Google Survey platform. Results illustrated that most Saudi female users of FDAs were aged between 18–24 years with 64.9%, 91.5% being single and 37% ordering food online within one to two days a month. There was a significant association between the influence of using FDAs during COVID-19 lockdown restrictions and age, education, and average days of ordering food online (p ˂ 0.05). Another important factor is that higher education was associated with more frequent use of the FDAs, there were direct relationships between education level and using FDAs, 58% of the participants were educated as undergraduate or postgraduate. Although lifestyle changes increased the use of FDAs during COVID-19 global lockdown restrictions, these changes may negatively affect individuals’ dietary habits and preferences, particularly adult Saudi females. These findings can aid in promoting healthy diet management globally and in Saudi Arabia unless the governments lead to significant beneficial changes toward improving food delivery applications.