Traffic-light labelling is having such an impact on its customers' purchasing behaviour that Sainsbury's has changed its new product development strategy to reflect this, the retailer told The Grocer this week.

The multiple has decided that, in future, all own-label product development will be undertaken with its colour-coded Wheel of Health labelling at front of mind - in a bid to avoid as many red lights as possible.

The chain has also begun to roll out the Wheel to its Basics range, and is midway through labelling the 8,000 own-label products that qualify for the label.

It is currently on all ready meals, sandwiches and the Taste the Difference range.

In the two years since the supermarket chain introduced the Wheel of Health, understanding of the signposting scheme has grown and shopping habits have changed, said Sainsbury's nutrition and health manager Beth Hart.

Sainsbury's research had shown that 94% of its customers found the Wheel of Health easy to understand and 74% said that traffic lights affected their buying habits. "The colour coding is the most important part of the Wheel for us," said Hart.

"It's a speedy ready reckoner for customers. We have invested a lot in this and our customers keep telling us that they like it.

"Although we have found that the red label does not stop our customers buying these products, we are finding shoppers are gradually making healthier choices. It's affecting our product development strategy as product developers are encouraged by the success of our healthier products."

Now any product in development was subjected to Wheel of Health calculations, and the recipe adjusted to avoid red labels, she said.

In a revelation that will surprise some health campaigners - particularly the National Consumer Council, which last year issued a report claiming budget ranges were less healthy - Sainsbury's Basics was proving to be a healthy range, with few red labels, said Hart.

Sainsbury's is planning a big promotional push on the Wheel of Health during the summer, with a raft of new healthier products and activity designed to educate customers.