Margarine is an ultra-processed spread originally invented in the 19th century as a replacement for butter which didn’t become rancid. The first recipe used beef tallow, so it definitely wasn’t a healthier choice. Over the years, margarine has evolved, and these days it’s mostly made with polyunsaturated fats or fortified with plant sterols.

Butter is made by churning large amounts of whole fat milk and contains about 80% saturated fat. Saturated fat has been consistently associated with blocked arteries, and increased risk of coronary heart disease, and stroke.  By contrast, polyunsaturated fats and the plant sterols in margarines have been shown to lower LDL cholesterol levels and therefore reduce the risk of heart disease. 

But it’s a bit more complicated than that. While there’s no doubt that saturated fat in meat contributes to arterial disease, there’s little evidence that it’s harmful in butter. Researchers believe this may be due to the bioactive compounds in butter, which counteract the effects of the saturated fat.

Both margarine and butter are very calorie dense – both spreads have approximately 700 calories per 100g, so overconsumption is not good for weight management and will likely lead to increased visceral fat around the belly.

But to answer the question, which is better for you? the polyunsaturated or plant sterol margarine wins. But if you prefer a smear of butter on your toast, it isn’t going to kill you.