Background: The frequency of visits to restaurants has been suggested to contribute to the pandemic of obesity. However, few studies have examined how individual use of these restaurants is related to BMI using new technology of reminding to avoid memory error. Aim: To investigate the association between the usage of different types of food outlets and BMI among adults in Scotland. Method: The study was cross-sectional. Participants (n = 681) completed an online survey for seven consecutive days where all food purchased at food outlets was reported each day. We explored the relationship between BMI and usage of these restaurants using auto-reminder text system. Results: Body Mass Index (BMI) of both males and females was not related to frequency of use of Full-Service Restaurants (FSRs), Fast Food Restaurants (FFRs), delivery or takeaways, when assessed individually, or combined (TFO= Total Food Outlet). Conclusion: These data do not support the widespread belief that consumption of food out of the home at fast-food and full-service restaurants, combined with that derived from deliveries and takeaways, is a major driver of obesity in UK.