As if they didn’t have enough on their plate trying to find a partner, single people are also being blamed for America’s snacking frenzy.

The growth in snack foods being consumed at meal time is largely driven by people who are eating alone, according to an online survey of over 350,000 snack times a year by market research firm NPD Group. Last year, the average American eating alone consumed a snack food as a meal 191 times, up from 167 times in 2011, equating to billions more snacks (and calories) every year. (This includes potato chips that are eaten alongside a main meal or just the potato chips as a meal replacement; the study didn’t distinguish the kinds of snacks.)

Smaller households and people eating alone are two of the key contributing factors, says Darren Seifer, NPD food and beverage industry analyst. The proportion of one-person households increased to 27% in 2012 from 17% in 1970, U.S. Census Bureau data found. In 2011, there were 32 million one-person households versus 23 million in 1990. In 2012, one-in-five adults ages 25 and older had never been married, a separate analysis of census data by the Pew Research Center found. In 1960, only about one-in-10 adults in that age range had never been married.

People living alone often don’t want to cook and buy too many groceries that go bad before they’re used, says Jill Weisenberger, a Yorktown, Va.-based registered dietitian nutritionist (RDN) and author of “The Overworked Person’s Guide to Better Nutrition.” Her clients tell her: “It’s hard to shop and cook for one.” That’s one reason why people are buying more snack foods, she says. “They are individually packaged and often have a very long shelf life. That, and an awful lot of people do not have cooking skills.”

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Why Americans are the world's biggest snackers

Around one-quarter of the average American’s daily calorie intake is due to snacks and effectively constitute a fourth meal, according to researchers at the 2011 expo of the Institute of Food Technologists, a nonprofit scientific society of those working in food science. “That doesn’t just mean one bag of snack chips at dinner,” Weisenberger says. “We really ought to be concerned about the nutritional value. That’s a large quantity of calories and should meet nearly 25% of our nutritional needs. That often isn’t the case.”

Americans have some of the worst snacking habits in the world. Fresh fruit is the No. 1 snack in Europe, the Middle East and Africa, according to a 2014 survey of 60 countries by research group Nielsen. Latin Americans prefer yogurt. But the No. 1 snack in the U.S. is potato chips. (Obesity rates in the U.S. currently stand at around 35% of the U.S. population, or nearly 79 million people, according to the Centers for Disease Control and Prevention. Here’s a calculator to estimate how many calories you need.)

People should strive to eat more fruits and vegetables for snacks, plus snacks that are low in sodium, says Heather Eicher-Miller, an assistant professor of nutrition science at Purdue University in West Lafayette, Ind. And they should avoid sugar-sweetened beverages and yogurts that are high in sugar. This is especially true for children, she adds. Weisenberger has a simple question people should ask themselves before putting quarters in the vending machine: “What haven’t I eaten enough of today? That’s what I should be eating.”

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