A recent ACNielsen global study on sleep habits suggests that one of the most profound lifestyle changes affecting many Americans has to do with when and how much they sleep - a shift that, while it may result in red eyes and cranky psyches, also can mean some real marketing opportunities for food retailers.

More than one-third of U.S. adults go to bed after midnight during the week, while nearly the same number (29 percent) are out of bed by six in the morning. And it isn't just Americans who are burning the midnight oil; in fact, the survey indicates that when comparing the percentage of adults who go to bed after midnight, the U.S. ranked 11th out of 28 markets.

Because we are living in a 24/7 world, it also means we aren't adhering to traditional mealtimes as in past generations. While it used to be that breakfast was served between seven and eight in the morning, lunch around noon, and dinner between six and eight pm, that's hardly the case these days.

People on the go may be eating breakfast as early as five in the morning, which means they are ready for lunch a lot earlier; it also means that they may be "grazing" during the day, eating small meals or snacks whenever they get hungry. In addition, foods that used to be reserved for certain times of day - cereal, for example - now may be eaten virtually any time as either a snack or a meal.

This means that food retailers and even food-service providers are creating new marketing programs that cater to these changing habits, much in the same way that diners used to make a big deal out of "serving breakfast all day." It means that there may be new ways to market healthy food for people who are hungry at odd hours because of chaotic schedules, but are looking for nutritious alternatives to fast food or convenience-oriented food.