Over the past six months, Elizabeth O’Herron has banished nearly all brand names from her household.

So long Pampers, Hefty, and Birds Eye. Instead, the pantry is stocked with cheaper imitations of the same goods: Wal-Mart’s diapers, BJ’s garbage bags, and Stop & Shop’s frozen veggies.

“I am not loyal to any grocery store or any brand,’’ said O’Herron, who estimates she saves at least $50 a month by buying generic brands. “I am loyal to savings.’’

A growing number of consumers like O’Herron are ditching their beloved Kellogg’s Raisin Bran and Wonder Bread for less expensive versions without the familiar packaging. Unit sales of private label goods have jumped 8 percent since 2007, while brand names have declined roughly 4 percent, according to Nielsen Co.

Many shoppers are finding that sugar, shredded cheddar, and milk peddled under store labels cost up to 40 percent less and often taste just as good as nationally known brands. Some items are even made by the same manufacturers.

Shoppers’ switch to store brands suits merchants just fine because they make a bigger profit from selling their own labels. This month, Supervalu , which runs several supermarket chains, including Shaw’s, unveiled plans to slash the number of items in various categories by as much as 25 percent so it can display store brands more prominently.

Europeans long ago began embracing private labels, realizing it involved little sacrifice and considerable savings. The recession has nudged Americans to the same realization. More than 40 percent of shoppers reported buying store labels instead of name brands, and 63 percent said they plan to purchase private labels after the economy rebounds, according to a survey of 50,000 grocery shoppers released last week by BrandSpark and Better Homes and Gardens.

“Store brands used to be nothing you wanted to buy. It was a compromise you’d make in quality in order to get something cheaper,’’ said Alan Klein, of the Marketing Agency Paris New York, a consultancy. “But the recession has been an awakening for some consumers. They are realizing that they can get equal or superior quality.’’

Retail analysts say the trend has made it harder and more expensive for national brands to get their products on the shelves at a time when many of these companies have reduced advertising budgets. This month, Procter & Gamble said it is launching an online shop this spring that will sell P&G products like Oil of Olay, Pampers, and Tide. A P&G spokesman declined to comment on the rise in store brands, but the company last fall responded to consumers’ trading down by lowering prices, including cutting the price of Cheer detergent by 13 percent.