Are millennials frivolous with their money? Not by this measure

Millennials have been caricatured as the "avocado toast" generation, financially irresponsible dreamers who fritter away their money rather than save it for more important things. Yet new research suggests that young Americans are spending more not just on eating out, but also on other items normally associated with, well, growing up. 

On average, millennials are outspending older generations by about $2,300 a year, according to a new survey from Bankrate.com. While some of the money is, in fact, spent at restaurants, much of their budgets are devoted to paying for groceries, gas and cell phone service, the survey found. 

Those categories highlight a trend that has been largely overlooked in the tendency to pigeon-hole millennials as pleasure-seeking spendthrifts: Many people in their late 20s and early 30s are starting families and settling down. 

"Restaurants and travel may be not that surprising, because it's all about experiences and brunching,"said Bankrate.com credit card analyst Robin Saks Frankel. "It's a little bit of a spending lifestyle, but not a lavish one."

Saks Frankel said much of the higher spending by millennials reflects where they are in their lives -- settling down, starting families and moving to more distant suburbs in order to afford housing. Higher gas spending could reflect the difficulty young adults are having finding affordable housing close to their workplaces or a city center, given rising real estate prices across much of the country, she said. 

Millennials spend an average of $254 per month on filling up their cars, compared with $211 per month for older Americans. When it comes to groceries, millennials spend $797 per month, compared with $724 per month for older generations. Young adults shell out an average of $233 for dine-in and take-out meals, while their elders typically spend $182 per month. 

"The older millennial group, that's the population that is settling down and starting families," she said. "If you have a young family, you tend to spend more on groceries."