A survey of nearly 700 popular meals served in celebrity chef and High Street restaurants found half were high in salt - equivalent to a red traffic light label on a supermarket product.
From their research, Consensus Action on Salt and Health (Cash) discovered that the 13 saltiest main meals contained more than the maximum recommended daily intake of 6g of salt.
Fast food outlets were also analysed.
Charities are urging chefs to use less salt in their food.
The survey measured the salt content of 664 main meals from 29 popular High Street and celebrity restaurants, fast food and cafes chains.
Analysis showed that 347 meals had more than 2.4g of salt per portion, which would earn them a red traffic light label for salt content.
A selection of main meals from six celebrity chef restaurants were analysed for their salt content including Brasserie Blanc (Raymond Blanc), Dinner (Heston Blumenthal), Frankies (Marco Pierre White), Jamie's Italian (Jamie Oliver), Fifteen (Jamie Oliver) and Savoy Grill (Gordon Ramsay).
From the celebrity chef restaurants tested, on average Jamie's Italian had the highest level of salt in their three dishes while Heston's Dinner was shown to have the lowest values of salt, all below 1.5g of salt per dish.
Celebrity chef restaurants and High Street chain restaurants both came out higher for salt content than cafes and fast food chains, partly due to the larger portion sizes.
In the fast food category, meals from McDonald's, Burger King, KFC, Subway, Pizza Hut and Dominos were all analysed as part of the survey.
Pizza Hut fared worst with 93% of their dishes analysed containing more than 2.4g of salt. Subway fared best with less than one in five meals getting a red traffic light label for salt, although their portions were smaller.
In the 20 saltiest meals from fast food outlets, a regular BBQ meat feast pizza from Pizza Hut was found to contain 6.36g of salt while Domino's pepperoni passion pizza contained 4.8g.
The survey found an average of 3.1g salt per meal - half a person's daily recommended amount of salt.
Alongside the analysis of dishes, Cash undertook a survey of public opinion on salt which found that 54% of 1,100 people surveyed found restaurant meals too salty, and nine out of 10 people believed that restaurants and cafes should let them choose if they want to add salt to their meal or not.
The Department of Health has previously said that reducing salt intake by just 1g per day - a pinch of salt - would save 4,147 preventable deaths and £288m to the NHS every year.
A high salt diet has been linked to a number of other serious health conditions such as stomach cancer, osteoporosis and kidney disease.
Tracy Parker, dietitian at the British Heart Foundation, said: "We're all eating too much salt and with one in six meals being eaten out of the home, it's important to keep an eye on our salt intake all the time.
"It's vital restaurants provide clear menu labelling showing us how much salt is our dinner, but chefs should ideally be cutting back on the salt they use and giving the diner the choice.
"Until then, using information on restaurants' websites before you go out can help you eat more healthily when eating out."
Graham MacGregor, professor of cardiovascular medicine at The Wolfson Institute of Preventive Medicine, Queen Mary University and chairman of Cash, said that too much salt is harmful.
"Salt puts up our blood pressure, and as a result, thousands of people die unnecessarily each year from strokes, heart attacks and heart failure.
"Whilst efforts have been made by foods in supermarkets to use less salt, chefs' preference for saltier foods is preventing further progress. It's clear from our survey that some chefs are not listening to their customers."
Eddie Gershon, spokesman for restaurant JD Wetherspoon, said they were open and honest with their customers about the salt content of their meals.
"Most of our dishes on Cash's list contain bacon, gammon or pork which are all meats which are high in salt.
"We give customers what they want and tell them which meals are high in salt on our website and the company's nutritional leaflet.
"We do reduce salt where possible in line with government guidelines."
A Pizza Hut spokesperson said they had reduced salt in their meals.
"We have invested heavily in salt reduction, cutting salt by 15% across our menu since 2006 and we'll continue to make reductions in line with consumers' attitudes and palates."
A spokeswoman for Jamie's Italian said the group's own testing showed salt levels were lower than Cash's figures, suggesting the dishes they tested must have been anomalies.
She also pointed out that extra nutritional training was being provided for chefs to help make the food served healthier.