Despite public health progress in cutting calories, as well as salt and fat from fast foods and supermarket products, neighborhood restaurants are still packing big helpings of each into their meals, a trio of studies suggests.

Small independent eateries are not required to display nutritional information for consumers - if they did, the researchers report, patrons would routinely see single meals containing nearly a full day's worth of calories and fat plus one and half times the daily recommended intake for salt.

"It's really a disgrace. Every day the newspapers say things about the obesity epidemic… To a large extent, you can trace that to too many calories," said Susan Roberts, director of the U.S. Department of Agriculture Energy Metabolism Lab and professor of nutrition at Tufts University, in Boston.

About two thirds of Americans are considered overweight or obese, according to the U.S. National Institutes of Health. And as American waistlines continue to expand, public health policy has focused on the quality of food available in supermarkets and restaurants.

For their analysis, Roberts and her colleagues measured the calories in 157 meals at small Mexican, American, Chinese, Italian, Japanese and Thai restaurants in and near Boston between June and August 2011.

Overall, the researchers found the average meal at those restaurants contained 1,327 calories. That's about 66 percent of the 2,000 daily calories recommended by the U.S. Food and Drug Administration.

About 8 percent of the meals exceeded 2,000 calories.

The meals from small restaurants also contained up to 18 percent more calories than comparable dishes from larger chains - suggesting the requirement to display nutritional information is keeping the large-chain restaurant meals healthier, according to the researchers.

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