Almost half of adults say they are ordering kids' meals. Here's why.

Almost half of U.S. adults say they're ordering from restaurant kid menus in order to save money when they go out to eat and to opt for smaller portions, new research shows.

About 44% of adults surveyed by Lightspeed Commerce, a provider of point-of-sale technology for hospitality businesses, said they're ordering from the kids' menus at restaurants. Kids' meals are traditionally less expensive than those on adult menus because portion sizes are usually smaller.

The trend comes as some consumers are cutting back on eating out, with McDonald's and Wendy's earlier this month reported sluggish breakfast sales. The companies attributed the trend to heightened economic uncertainty and pressures facing low-income consumers.

Adult diners said smaller portions, simpler menus and lower prices are compelling them to turn to kids' menus, Lightspeed said.

"Whether it's a mini burger or mac and cheese, the kids' menu is becoming a smart option — not just a nostalgic one," Lightspeed researchers said.

At McDonald's, a six-piece chicken McNugget Happy Meal, which comes with fries, milk and apple juice, costs $5.99. By comparison, an order of six McNugget's from the burger chain's McValue menu costs $5.59, but doesn't include fries or drinks.

Eating at restaurants has become more costly, with the most recent consumer price index data, which measures changes in the price of everyday goods, showing that the cost of dining out has risen 3.9% over the past 12 months.