PepsiCo is reducing the saturated fat content of its Walkers bagged snack brands by 80% and cutting their salt content by a quarter, as part of its strategy to boost the health credentials of the Walkers portfolio.

From next month its Quavers, Wotsits, Monster Munch, Squares and French Fries products will be made with Sunseed oil, which is higher in healthier monosaturated fat and lower in saturated fat.

Smarter pack designs are being introduced to coincide with the move.

Packs will also carry GDA labelling for the first time alongside the Sunseed logo, as well as a flash highlighting the reduction in saturated fat and salt.

PepsiCo switched its main Walkers crisp brand to Sunseed oil at the start of last year, cutting the saturated fat content by 70% - a move that was instrumental in reversing a 7.3% value decline in 2005 to a 3.7% growth in sales last year.

It hopes the switch to Sunseed oil in its snacks brands will also bring the category, which is down in value by 0.9%, back into growth.

"We had a fantastic response to the changes we made to Walkers crisps last year and saw the category grow," said Jon Goldstone, vice president of marketing at Walkers.

"Snacks has been in decline, but we anticipate these developments in our range are set to put it back in growth and therefore boost the overall category performance. We are well positioned to turn around the category."

The relaunch is being supported by a £5m TV, press and direct mail advertising campaign from March that will follow a similar informative theme to the adverts for the crisps relaunch.

"They will be simple ads," said Goldstone. "Mothers want to be told the facts but we have got five brands with a lot of heritage and the challenge will be to get the health message across all these brands."

In a separate campaign, the Walkers crisps brand will be back on television in support of Comic Relief, which takes place on 16 March.