Swapping saturated fat for healthier sources of energy does cut the risk of heart disease, a large study suggests.
New research shows that replacing just 1 per cent of daily calorie intake from saturated fat with other sources of energy - such as whole grain carbohydrates or polyunsaturated fats - cuts the risk of heart disease by 6 to 8 per cent.
The study, published in the British Medical Journal, is the latest to throw its weight behind official NHS recommendations which say saturated fat should be limited in order to protect against heart disease.
Saturated fatty acids are found in hard cheese, whole milk, butter, beef, and chocolate
Other studies have questioned this health message, with some claiming there is no evidence that saturated fat causes a problem.
The new research, from experts at the Harvard school of public health and Harvard medical school in Boston, found that a higher intake of major saturated fatty acids, such as those found in hard cheese, whole milk, butter, beef, and chocolate, was linked to an increased risk of heart disease.
They analysed data from two large US studies involving 73,147 women followed between 1984 and 2012, and 42,635 men followed from 1986 to 2010, none of whom had heart disease at the start of the study.
Diets were tracked every four years and experts looked for incidents of heart disease or deaths linked to heart disease.
Between 9 per cent and 11 per cent of daily calorie intake was made up of saturated fat among those taking part in the study.
But those people who consumed the lowest amount of saturated fat compared to those who consumed the most could enjoy a lower risk of heart disease.
The experts said saturated fat should be replaced with equivalent energy from polyunsaturated fats and monounsaturated fats - found in some spreads, oils and nuts and seeds - and whole grain carbohydrates, such as breads and cereals, or plant proteins, such as beans and lentils.
The researchers concluded, "Dietary recommendations should remain on replacing total saturated fat with unsaturated fats or whole grain carbohydrate, as an effective approach towards preventing coronary heart disease."
TV doctor Dr Sarah Jarvis said, "This study is exactly what we need to ease consumer confusion on fats. The saturated fat content of so many of our favourite foods can have very serious consequences and it's crucial that we acknowledge the role of our diet in increasing or decreasing our risk of heart disease.
"There are many conflicting opinions, but this research backs up official health guidelines that have remained the same for decades; replace saturated fat with unsaturated fat for good heart health."
But Dr Aseem Malhotra, cardiologist and advisor to the National Obesity Forum, said, "This observational study cannot prove cause and effect whereas more robust randomised controlled trials have shown that reducing saturated fat in the diet does not reduce heart attack or risk of death.
"Nevertheless, we need to move to dietary guidelines that focus on whole foods which include lots of vegetables, olive oil as base fat, nuts and oily fish and one that's low in refined carbohydrates and sugar.
"If you stick to that, as I advise my patients, having full fat dairy and non processed red meat on occasion will not do you any harm."
In March, a study found that cooking oils and spreads rich in a type of polyunsaturated fat help lower cholesterol but do nothing to cut the risk of heart disease or death compared with eating butter.
Experts from the prestigious National Institutes of Health in Maryland said that while people may experience lowered cholesterol levels, this does not translate to improved survival or lower risk of heart disease.