Menu labels are meant to help people make informed food choices. But when it comes to salt, new research suggests those numbers often come with a wide margin of error.
A study led by researchers at the University of Reading found that nearly half of analyzed takeout (often called “takeaway” in the UK) meals contained more salt than their menus declared. The findings, published in PLOS One, point to substantial variability in salt content across similar dishes and restaurants.
Researchers analyzed 39 takeout meals purchased from 23 outlets across Reading in the United Kingdom, including both national chains and independent restaurants. Among meals that provided salt information, 47% exceeded the amount listed on the menu. In some cases, a single portion contained more than the UK’s recommended daily salt intake of 6 grams.
Pasta dishes were particularly salt-heavy. On average, they contained 7.2 grams of salt per serving, exceeding daily guidelines in one meal. One pasta dish contained as much as 11.2 grams. Meat pizzas had the highest salt concentration by weight, at 1.6 grams per 100 grams, while curry dishes showed the greatest variation, ranging from 2.3 to 9.4 grams per portion.
By contrast, traditional fish and chip shop meals tended to contain less salt than expected. Chips from fish and chip shops averaged just 0.2 grams of salt per serving, compared with about 1 gram per serving from other outlets. Researchers attributed this difference to preparation practices, noting that salt in fish and chip shops is typically added after cooking and only if requested.
Professor Gunter Kuhnle, who led the study, said variability in how meals are prepared makes precise labeling difficult.
“We conducted this research because we suspected that many menu labels were inaccurate on salt,” Kuhnle said. “Variations in preparation methods, ingredients used and portion sizes mean food labels are often guess work. It's virtually impossible to know exactly how much salt is being added to your dinner.”
While packaged foods sold in shops have seen gradual reductions in salt levels over recent years, eating out presents a different challenge.
“Food companies have been reducing salt levels in shop-bought foods in recent years, but our research shows that eating out is often a salty affair,” Kuhnle said. “Menu labels are supposed to help people make better food choices, but almost half the foods we tested with salt labels contained more salt than declared. The public needs to be aware that menu labels are rough guides at best, not accurate measures."
The researchers emphasize that the findings should not be interpreted as evidence of deliberate mislabeling. Instead, they reflect the practical challenges of standardizing recipes and portion sizes in restaurant settings, particularly in independent outlets.
Excess salt intake is a major public health concern. The World Health Organization estimates that high sodium consumption contributes to 1.8 million deaths worldwide each year, largely through its effects on blood pressure and cardiovascular disease.
The study adds to growing evidence that while menu labeling can offer useful context, it cannot always capture the true nutritional variability of meals prepared outside the home.
The authors reported receiving no specific funding for this work.