New Yorkers will soon know when they eat a day's worth of salt in one sitting.

On Wednesday, the New York City Board of Health voted unanimously to adopt a new rule requiring chain restaurants to label menu items with more than 2,300 mg of sodium.

That's a full day's worth of salt, according to a memo from the board, and an estimated 80% of New Yorkers consume more than that recommended maximum each day. That's still better than the nationwide number: an estimated 95% of Americans consume too much salt.

Studies show high sodium intake leads to cardiovascular disease -- the leading cause of death in New York City -- along with hypertension, high blood pressure and increased risk of stroke.

"New York City was the first jurisdiction in the nation to adopt high sodium label warnings, and the health department expects this rule will further improve the overall health of New Yorkers," the city's health department said in a statement Wednesday.

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The salt industry and restaurant owners pushed back against the new rule. The president of the Salt Institute, a trade association of salt producers, called it "unnecessary."

"This is another example of the government creating policy based on outdated, incorrect sodium guidelines that have been refuted by ten years of research," President Lori Roman said in a statement. She pointed to some studies that found a low-sodium diet can have adverse affects in some people.

The New York State Restaurant Association said adding the labels would require "costly new menu boards."

"This is just the latest in a long litany of superfluous hoops that restaurants here in New York must jump through," a statement from NYSRA CEO Melissa Fleischut says. "Every one of these cumbersome new laws makes it tougher and tougher for restaurants to find success."

New York City was also the first jurisdiction to require calorie labeling on menus. As with that rule, salt labeling will apply only to restaurants in New York City that have at least 14 other locations nationwide -- which are mostly fast food chains like Wendy's, Subway and McDonald's (MCD).

A health department spokesperson said the new rule will affect about 12.5% of the city's 24,000 restaurants. It will go into effect December 1, though the health department said it will offer a grace period.