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.

It was taken to the castle in a procession led by a giant King John figure.
The city holds one of four remaining original copies of the charter, which was signed by King John at Runnymede in 1215.
Schoolchildren who helped make the facsimile also joined the procession.
A trail of 25 decorative sculptures have also been installed in Lincoln - each representing one of the barons who were present at Magna Carta's sealing.
Organiser David Hill said: "We've got a 20m-long parchment - which is a facsimile of the original - and on top of it are words and designs from schoolchildren in the city."
Emma Tatlow, from Visit Lincoln, said the anniversary was helping attract tourists to the city, with more than 70,000 visiting the charter at the Lincoln Castle since April.
Magna Carta outlined basic rights with the principle that no one was above the law, including the king.
It charted the right to a fair trial, and limits on taxation without representation.
It inspired a number of other documents, including the US Constitution and the Universal Declaration of Human Rights.
Only three clauses are still valid: the one guaranteeing the liberties of the English Church; the clause confirming the privileges of the City of London and other towns; and the clause that states that no free man shall be imprisoned without the lawful judgement of his equals.
The British Library has two copies of the 1215 Magna Carta.
Source: The British Library

Brian Farrell admitted conspiring to distribute heroin, cocaine and methamphetamine, in March this year.
Silk Road 2.0 was shut down in 2015, following Operation Onymous, raids that targeted almost 400 suspected illicit marketplaces around the world.
At the time, it was generating sales of about $8m (Â£5.5m) a month and had about 150,000 users.
Ross Ulbricht, who set up the original Silk Road, was sentenced in May 2015 to life in prison on several charges including distributing drugs.
Silk Road 2.0 was a copy of the original site and allowed people to use bitcoins to anonymously buy and sell drugs and other illegal goods and services via the Tor dark web network.
Farrell, who operated online using the alias "DoctorClu", had admitted his involvement with the site when prosecutors had been searching his Washington home in 2015, court papers revealed.
Blake Benthall, arrested in 2014, denies creating the Silk Road 2.0 site.
A Kent council has voted to restrict the opening hours of fast food outlets near schools in a bid to tackle rising obesity.
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The 800th anniversary of the Magna Carta has been celebrated in Lincoln with a delivery of a facsimile of the parchment to Lincoln Castle.
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An American who helped run a successor to the Silk Road drug marketplace has been sentenced to eight years in jail.