For many people, a full English breakfast is one of the highlights of the weekend. But polishing off a plate of eggs, bacon and sausages may be doing even more harm than previously thought.
Scientists have discovered that eating just two fatty breakfasts in a row can trigger changes in the body which could increase the risk of heart disease.
Volunteers who had their blood tested after eating a full English on two consecutive days saw a steep rise in cardiac biomarkers - the cells and chemicals known to be linked to heart trouble.
Doctors have known for years that a diet high in saturated fats can trigger a build-up of fatty deposits in the arteries around the heart. But it had been thought that any damage occurred months or even years later.
However, the latest study suggests the heart disease process starts within hours.
Despite this, surveys show the full English remains the favourite way for many Britons to start the day.
Researchers at the University of North Texas recruited seven healthy women and fed them a breakfast sandwich containing bacon, sausage, egg and cheese, and some hash browns.
The meal contained more than 70 per cent fat and accounted for over two-thirds of their recommended daily calorie intake. Doctors took blood samples every hour for six hours to measure changes in levels of fats and biomarkers linked with heart damage.
The experiment was repeated the next day and the results revealed an increase in eight of the 19 different biomarkers which indicate future cardiac problems.
These included monocytes, the white blood cells thought to trigger inflammation in blood vessels which could lead to blocked arteries. In a report, the researchers said: "The magnitude of change in such a short time was not expected." The British Heart Foundation said the findings highlighted the dangers of fatty diets. Dietician Tracy Parker said: "Most people eat too much saturated fat. Eating fried bacon and sausages will increase your risk of heart disease."
Professor Stephen Westaby, a heart surgeon based at Oxford's John Radcliffe Hospital, said it may be that heart disease biomarkers initially soar if someone is not used to eating fatty foods but settle down as the body adapts. He added: "It wouldn't put me off enjoying full breakfasts for a few days."