For years they have been blamed for increasing our risk of heart disease, but now it appears that they may not be quite as bad for us as we once thought
Can you remember when it was OK to eat saturated fats? To gobble a bacon butty, dripping with butter, without worrying that your arteries were furring up with every bite? For 20 years medical research has presented saturated fats (found in animal and full-fat dairy products) as major contributors to the development of heart disease. National guidelines on diet encourage that our fat intake is mostly unsaturated (from fish and plants), with only small amounts from saturated sources (cream and butter). But last week a paper in the Annals of Internal Medicine found the existing evidence does "not clearly support" such guidelines. The research - a meta-analysis pooling data from 72 existing studies on fat intake - looked at the effects of different fats on the risk of heart disease, defined in various studies as coronary artery disease, angina, a heart attack or sudden cardiac death.
It compared the risk for people in the top third of fat eaters with those in the bottom third and found only trans fatty acids - mostly found in processed oil-based products - were associated with an increased risk of heart disease. Earlier this month an editorial in the BMJ journal, Open Heart, also argued that the fat question was still controversial. Reducing saturated fats in the diet means that people tend to increase their calories by eating more carbohydrates or switching to polyunsaturated fats. Increasing carbohydrates, argues the editorial, increases the risk of diabetes and obesity, while eating the wrong polyunsaturated fat (omega-3, from industrialised vegetable oils, as opposed to omega-3 from salmon, olive oil, seeds) can lower the protective form of cholesterol and cause an inflammatory reaction in the walls of arteries, effectively increasing the risk of heart disease. So, does this mean there is no link between saturated fats and heart disease?
This latest study does not prove you can eat more saturated fats than currently recommended (30g a day for men and 20g for women). It merely suggests that saturated fats may not be as responsible for heart disease as once thought. There are now known to be other villains, such as sugar and refined starch, which cause heart damage through obesity. There is, however, no evidence that a low-fat diet is good for you. In fact, there is increasing evidence that we need to think about our whole diet and not concentrate on the effect of individual nutrients.
A Mediterranean diet without too much pasta is likely to fit the bill. Dr David Katz, in an overview of diets in The Annual Review of Public Health concludes that we should eat "food, not too much, mainly plants". The healthiest diet is likely to consist mostly of vegetables, fruits, nuts, beans and seeds (including oil such as olive oil), with some fish, meat, eggs and diary. And the occasional slice of chocolate cake to keep things real.
Photo: National guidelines on diet encourage that our fat intake is mostly unsaturated. Photograph: Getty Images