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A typical U.S. restaurant meal provides enough calories for two or more healthy meals — and that's not just true in fast-food and large chain restaurants, according to a new study.

Independent restaurants and chains with fewer than 20 outlets won't be required to post calorie counts under a nationwide law that goes into effect at the end of this year, but that doesn't mean their meals are any better for the waistline, researchers say.

On average, meals from the non-chain restaurants contained about 1,200 calories each, which is more than half the daily requirement for most women and about 44 percent of the daily requirement for men, the study found.

"Fast food restaurants get blamed all the time, but as this study shows the small chains and individual restaurants that don't post nutrition information are just as bad when it comes to excessive portion sizes," said senior study author Susan Roberts, a researcher at Tufts University in Boston.

Between 2011 and 2014, Roberts and colleagues collected and analyzed a total of 420 meals from randomly selected non-chain restaurants in three U.S. cities: Boston, San Francisco and Little Rock, Arkansas. For comparison, they also collected 56 meals from large-chain restaurants in the same cities.

Overall, they found that 92 percent of the meals contained more than 570 calories, which they call the benchmark calorie count in a single meal for a woman who needs about 2000 calories a day to maintain the same weight.

Some cuisines were consistently heavier in calories than others, the researchers found. American, Chinese and Italian meals all averaged about 1,500 calories, while Greek, Japanese and Thai meals averaged 900 to 1,100 calories.

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When the study team compared the large-chain meals with similar non-chain meals, the big chains' meals averaged 68 calories less than their non-chain counterparts, according to the results in the Journal of the Academy of Nutrition and Dietetics.

Humans have "a whole biological system designed to get us to eat the food in front of us so large portions encourage overeating, not just because we are weak willed but because our biology is pushing us to finish our plate," Roberts said.

"That is so important - it means people can stop blaming themselves for overeating when they eat out and start blaming the restaurants for setting us up," she said.

Roberts would like to see legislation push restaurants to price their meals by portion.

"So, say you want the lasagna on the menu but only want a one-third portion, you could order that amount and pay one third of the price," Roberts said. "It would completely take away the current incentive that restaurants have to overfeed people."

Without such a proportional pricing concept, calorie counts should be required on the menus of all restaurants, not just large-chain and fast food places, Roberts added.

"We may think we are automatically eating healthier by choosing to dine at a location other than a fast food or large chain restaurant, but it seems like we are only fooling ourselves," Allie Matarasso said in an email.

It's unlikely that new legislation targeting smaller restaurants will be put into effect anytime soon, so it is important to know how to avoid excessive energy intake while dining out, said Matarasso, a clinical dietitian with Montefiore Health System in New York City, who wasn't involved in the study.

Sharing a meal with a friend or asking the waiter to serve half the meal and pack up the other half to take home are ways to decrease the portion size and reduce the temptation to overeat, she said.

It's also important to know what healthy portion sizes look like, Matarasso added. "A serving of protein should be approximately the size of the palm of your hand and starch should be about the size of your clenched fist," she said.

It's also beneficial to practice basic principles of healthy eating regardless of where you're dining, she said. These include ordering items that are baked, broiled, steamed rather than fried, asking for sauce or dressing on the side, loading up on vegetables, choosing whole grains, and avoiding calorie-containing beverages.