Obesity could be linked to a high salt intake – regardless of overall calorific consumption, a new study has found.

The claims were published in the scientific journal Hypertension and used data for more than 450 children and 780 adults from the UK National Diet and Nutrition Survey 2008/2009 to 2011/2012. Experts analysed urine samples over 24 hours and calculated calorie intake from a four-day diary.

The results showed that salt intake in urine was higher in people who were overweight or obese, with an extra gram of salt a day leading to a more than 20% increase in the chance of being heavy.

Disease

Graham MacGregor, professor of cardiovascular medicine at Queen Mary University of London and chairman of Consensus Action on Salt and Health, said: “The food we eat is now the biggest cause of ill health through its high salt, fat and sugar content added by the food industry.

“High blood pressure and obesity both lead to the development of cardiovascular disease, stroke, heart attacks and heart failure, which are the commonest causes of death and disability in the UK.”

However, Barbara Gallani, director of regulation, science and health at the Food and Drink Federation, said: “The suggestion of a direct link between salt intakes and obesity that CASH has reported is interesting, although more research is needed to identify any potential mechanisms involved.”

And Professor Susan Jebb, a government advisor and diet expert at the University of Oxford, urged caution. She said:  “Since energy intake was self-reported, there is no way to be confident in this assertion. Salt reduction is important to reduce cardiovascular risk but the combination of a weak study design and lack of any strong mechanistic basis for the association between salt and fatness means that this study should not detract from the main cause of weight gain which is consuming too many calories.”