When historians look back at the year 1970, they might focus on events such as antiwar protests and the breakup of the Beatles.
When food historians look back, many may recall a very different event: the debut of Hamburger Helper. The inexpensive pasta-and-powdered-mix product - coming half a decade before microwave ovens went mainstream - quickly became popular among working mothers with less time to cook.
The dish, to which beef could be added, now represents the grandmother of a burgeoning food category: all-in-one meal kits. Like Hamburger Helper, the new kits are based on the concept of bringing together different elements of a meal - usually dinner - into one package.
Think of them as the civilian versions of the military's "meals ready to eat" (MRE), although marketers would prefer that they conjure up family dining - not chow time spent sitting on your ammo box.
In the early 1990s, Green Giant debuted its "Create A Meal," which added an assortment of vegetables to the powdered-sauce-and-pasta formula. Now, food manufacturers are broadening the meal-kit category to include an array of food combinations. In most cases even meat is included.
Meal-kit offerings currently in supermarkets include Campbell's Supper Bakes, Hormel's Dinty Moore Classic Bakes, General Mills' Betty Crocker Complete Meals, and ConAgra's Banquet Homestyle Bakes. The kits typically include about five servings and cost about $5.
But consumers can't just stick the kits in the oven - and that's part of the allure. Most of the kits require some work, like mixing the dried sauce with the meat and pouring it all into a baking dish.
"The opportunity to touch the ingredients, to be involved with cooking it, but not do it all, is very important to many people," says Marlene Johnson, a spokeswoman for Betty Crocker.
Convenience, mixed with a dash of labor, is the perfect recipe for American parents - often moms - seeking to spend less time in the kitchen without totally abandoning their roles as family mealmakers.
"These meals give the aura of home cooking that many mothers are looking for," says Barbara Haber, food historian and author of "From Hardtack to Homefries: An Uncommon History of American Cooks and Meals."
Home cooking has lost some ground over the past decade. In 1991, Americans bought an average of 91 takeout meals. By 2002, that number had jumped to 118, according to the NPD Group, a Port-Washington, N.Y., market-research firm.
And takeout took on new forms. By the mid-1990s, supermarkets began installing prepared-meal centers, where consumers picked up items such as fully cooked rotisserie chickens.
Food manufacturers soon followed suit, say experts, offering a wider range of prepared meals. "They realized that the long-term trend was away from tending [to] and cleaning up [after] three or four different items," says Harry Balzer, NPD Group vice president, who has been tracking Americans' eating habits for 23 years.
The economic slump has recently driven more people to eat in, and the number of meals Americans make at home has increased, say experts.
Meal kits are not only simple to put together, but they are less expensive than restaurant takeout. Sales in the US have risen steadily over the past few years. More than 64 million all-in-one meal kits were sold for the one-year period ending May 17, a 14.6 percent increase from the previous year, according to ACNielsen, which tracks supermarket sales data.
Betty Crocker's line of Complete Meals is representative of the category. The line includes chicken and buttermilk biscuits, lasagna and meat sauce, and ham and au gratin potatoes, among other meals.
The kits, which are "shelf stable" and are enclosed in a paperboard box, contain two cans of Progresso meat and vegetables in sauce; a pouch of biscuits, pasta, or potatoes; and seasoning packets.
Preparation requires mixing the meat, vegetables, and sauce with the seasoning, and spreading the separate biscuits on top. Skillet-ready pasta-and-meat meals, sold frozen in bags, offer even easier preparation - but may reduce the process a little too much.
Superfluous labor may seem out of place in a culture that prizes convenience. But food manufacturers have been designing their products similarly for more than 50 years.
"Every era has had its version of this sort of story," says Ms. Haber.
In the 1950s, for example, the first cake mixes available in supermarkets just required women to add water, mix, and pop the cake in the oven. Manufacturers soon realized that women felt the recipe did not allow them to participate enough in the baking, so they left eggs out of the mix.
In the 1980s, microwave manufacturers published several series of cookbooks intended to promote the device as a quick way to cook quality food.
But Americans never adopted it as a primary tool for cooking, says Haber, partly because of their impression that it wasn't as legitimate as oven-based cooking.
"Women's responsibility has continually been an issue, and some solutions are more successful than others in answering this dilemma," says Haber.
But meal manufacturers are finding new ways to make low-maintenance cooking more palatable.
New flexible cans and pouches better absorb heat, cooking the food inside more evenly.
Packaging experts have also found ways to make cans and plastic packages that do not alter the taste of subtly seasoned foods. (Credit such advances, in large part, to the trickle-down of military technology.)
"Five years ago, it was less possible to get such extremely sensitive food products into these packages," says Ben Miyares, a spokesman for the Packaging Machinery Manufacturers Institute.
Despite the leaps in technology, experts say Americans will probably never abandon traditional forms of cooking altogether. But buying fresh ingredients and cooking several dishes in one meal might become more of a leisure exercise - perhaps something to save for the weekend.
"The desire to have 'involvement' will especially occur when cooking becomes recreational," says Mr. Balzer.