Takeaway food outlets offer limited seating and sell hot food to be consumed away from their premises. They typically serve energy-dense, nutrient-poor food. National planning guidelines in England offer the potential for local planning policies to promote healthier food environments through regulation of takeaway food outlets. Around half of English local government areas use this approach, but little is known about the process of adoption. We aimed to explore experiences and perceived success of planning policy adoption. In 2018 we recruited Planning and Public Health professionals from 16 local government areas in England and completed 26 telephone interviews. We analysed data with a thematic analysis approach. Participants felt that planning policy adoption was appropriate and can successfully regulate takeaway food outlets with the intention to improve health. They identified several facilitators and barriers towards adoption. Facilitators included internal co-operation between Planning and Public Health departments, and precedent for planning policy adoption set elsewhere. Barriers included "nanny-state" criticism, and difficulty demonstrating planning policy effectiveness. These could be considered in future guidelines to support widespread planning policy adoption.