General Mills Inc. (GSI) is converting all of its breakfast cereals to whole grain, making it the latest food company to undergo a nutritional makeover amid growing pressure from the government and consumer groups.

The move announced Thursday by the nation's second-largest cereal maker affects 29 cereals, including such popular brands as Trix, Golden Grahams (search), Lucky Charms and Rice Chex (search). The new recipes and packaging will be launched in October, he said.

General Mills officials said the whole-grain switch is designed to make it even easier for consumers to eat healthy food. Several of the company's brands, including Cheerios, Wheaties, Total and Wheat Chex (search), are already whole grain.

Company spokesman Tom Johnson said just over 40 percent of the company's cereal line is being changed, "so it's a huge undertaking." He declined to specify the cost of the changeover.

The decision follows a recent recommendation by a federal advisory panel. The panel, looking at ways to update the Agriculture Department's (search) familiar food pyramid, recommended eating whole grain products rather than refined grains to reduce risks of heart disease and other conditions.

At the same time, there has been growing questions about whether food companies could be held legally responsible for America's obesity epidemic and other health problems.

The scrutiny has prompted a handful of companies to offer, or at least consider, healthier versions of existing products.

Fast food restaurant chains McDonald's Corp. (MCD) and Wendy's International Inc. (WEN) have also revamped their children's menus to promote milk and fruit consumption.

Last year, Kraft Foods Inc. (KFT) began reducing the fat content in 200 products in North America and capping portions for single-serve packaged snacks. It also quit marketing snacks at school.

General Mills officials said it had done extensive taste tests with consumer panels on the revamped cereals.

"Consumers are looking for food products that can be part of a healthy, balanced lifestyle," Steve Sanger, the company's chairman and CEO, said in a statement announcing the change. "This innovation brings important health news to the cereal aisle. Delivering whole grain across our entire Big G cereal portfolio will benefit the people who love our cereals and should be good for the entire cereal category."