The South Australian government has turned to the French to help curb childhood obesity.

The government will introduce a program already considered a success in French schools to help children maintain a healthy weight and get fit.

It will be introduced in as many as 200 local schools over the next four years.

Called EPODE or Ensemble, prevenons l'obesite des enfants (Together, let's prevent obesity in children), it involves measuring and weighing every year to calculate their body mass index.

Parents are then advised about their child's weight and provided with guidelines for diet and physical activity.

Local doctors also support the program while dieticians visit schools and organise lectures on healthy eating for parents.

Health Minister John Hill said EPODE had proved successful in France and had since been introduced in Spain and Belgium.

"According to SA data, one in five four-year-olds is overweight or obese, while obesity levels in adults are 21.3 per cent compared to just 9.8 per cent in 1992," Mr Hill said.

"As a community the cost is enormous, the cost of obesity alone has been estimated at around $21 billion for Australia or around $1.6 billion for SA each year.

"We are already doing much about it, but we need to do more and this program will be a big part of our efforts."

However, the South Australian opposition criticised the plan, saying more than 500 public schools would miss out.

"Childhood obesity is worsening and the government's response is to roll out a campaign in which hundreds of schools will miss out," said opposition education spokesman David Pisoni.

"Obesity does not discriminate between schools but the government's program does."

AAP