Poor children in England are already at a disadvantage economically and due to this, are less socially mobile. But while they have to battle for their place in higher education and their careers, they also face the depressing prospect that they’re likely to become overweight or obese.

A Fabian Commission on Food and Poverty report (pdf) in 2015 showed that poor children are more likely to become obese than a decade ago because of the lack of access to healthy food. They’re also one and a half times more likely to get type II diabetes, which is related to weight, than those on higher incomes. It pointed out that while, on average, UK households spent less on food than ever as part of their budgets, low-income families spent over a third of their budget on food.

Fast food takeaways are usually a go-to for the cash strapped. You can get a bag of chips (fries) for just £1 ($1.34), a tray of fish and chips, brimming with all the trimmings like peas and gravy, for under £5, and even a box of fried chicken that can be as cheap as £3. But considering just the bag of chips alone comes in at 1,000 calories (pdf), which is half the daily allowance for 7 to 10-year old girls and boys, and is pumped full of fat and nutritionally poor ingredients, you can see how easily it is to pile on the pounds.

But it’s not as easy to say that poor children have the real choice not to eat fast food, especially when their parents are poor. Those outlets feed off poverty and expand, the poorer communities get. A UK government report (pdf) showed that over the recession in 2008/2009, there was an 8.2% growth in fast food premises in the UK’s top 10 cities and “this may influence peoples’ ability to make healthy choices.”

Now match this up with new data from Cambridge University’s Centre for Diet and Activity Research (Cedar), provided to The Guardian, and it shows that not only are fast food takeaways continuing to expand at a rapid rate, they are mostly popping up around schools. Currently, there are 400 schools in England that have 20 or more takeaways within just a 400-meter radius. If you look at the bracket of 10 to 19 takeaways, 1,400 schools are exposed to that many takeaways within the same distance. London has it the worst—17 out of the 20 English local authorities with the highest average number of takeaways near schools, are from the capital.

This is a big problem. A third of children aged two to 15 are already obese or overweight, according to Public Health England (PHE), and in the capital, 40% of children are already considered overweight or obese by the time they finish primary school.

The Mayor of London, Sadiq Khan, is already planning to ban fast food takeaways within a 400-meter radius of schools, but perhaps the government should follow his lead and roll that plan out across the country.

Read more: The benefits of tackling obesity in kids extend into adulthood