Medway Council is to stop new takeaways opening near secondary schools at lunchtime and near secondaries and primaries after school.
The council said there were currently 179 takeaways within 400m of a school.
The British Retail Consortium (BRC) said it was simplistic to treat all fast food restaurants in the same way.
The restrictions will be used as guidance when the planning committee considers new planning applications.
Councillor Jane Chitty said Medway's public health and children's services were extremely concerned about obesity.
"Allowing the planning committee to take this guidance into account is a positive step," she said.
Local authority health profile figures show 30% of adults in Medway are obese, while the average for England is 24.2% and the wider South East 23.7%.
Among children in Medway, 20% of 10-year-olds are obese.
"To do nothing is not an option," said Councillor David Brake.
"We are already seeing the effect obesity has on our National Health Service and anything we can do to prevent this at an early age is welcome."
A secondary and grammar school that responded to a six-week consultation on the restrictions supported the restrictions.
But the Kent Small Business Federation has called them draconian and said obesity needed to be tackled by changing behaviour.
The BRC said local authorities should encourage companies that wanted to play a positive role in public health and target those that were less responsible.
"There are those that are working positively to cut obesity by removing fats and sugars from food and giving clear calorie labelling on their menu boards to help customers make healthier choices," said director of food and sustainability Andrew Opie.
A Kent council has voted to restrict the opening hours of fast food outlets near schools in a bid to tackle rising obesity.