Margarine has been the chameleon of manufactured food products, able to transform its nutritional appearance, adapt to changing nutritional fads, and charm unwitting nutrition experts and nutrition-conscious consumers.

While research published by nutrition scientists in the early 1990s on the harmfulness of the trans fats in margarine temporarily unveiled its highly processed and degraded character, it has subsequently been reinvented as a trans-fat-free, cholesterol-lowering “functional food”.

From its invention in the late 19th century until the 1960s, margarine was considered by most people to be just a cheap imitation of butter, and was mainly consumed by those who couldn’t afford the real thing.

Margarine producers aimed to do little more than simulate the taste, texture, and nutritional profile of butter – by adding vitamins A and D, for instance.

When fats became good and bad

The promotion of margarine as a heart-healthy spread by nutrition experts began with the emergence of the distinction between so-called “good” polyunsaturated fats and the “bad” saturated fats.

This distinction was based on an association scientists had detected between saturated fats and heart disease risk, and on an indirect causal link to cardiovascular disease via blood cholesterol levels.

This vilification of saturated fats introduced the really novel idea that some naturally occurring nutrients are “bad”. But to describe nutrients as good or bad was really a simplification and exaggeration of the scientific evidence of their roles in the human body.

Nonetheless, such was the conviction of most nutrition experts in their new theories of good and bad fats that they were willing to override concerns about the highly processed character of margarine.

This included ignoring the fact that some of the polyunsaturated fats in margarine had been chemically transformed into trans fats during the hydrogenation process used to solidify vegetable oils.

And some early evidence that trans fats and partially hydrogenated vegetable oils have much the same effects as saturated fats on blood cholesterol levels was largely ignored.

Through the nutritionism prism

Nutrition experts’ promotion of margarine as a more healthy spread than butter was an important landmark in the triumph of what I call the ideology of nutritionism.

Nutritionism refers to the reductive focus on nutrients as a way of evaluating and comparing the healthiness of foods, which has dominated nutrition research and dietary advice for much of the past century. It’s characterised by simplified, exaggerated, and decontextualised explanations of the health effects of particular nutrients.

At the same time, other ways of evaluating food quality, such as on the basis of the level and type of processing a food has been subjected to, have been systematically undermined.

Based on this reductive nutritional ideology, the hierarchy of butter and margarine was turned on its head as the imitation came to be considered better than – and more real than – the original.

In this sense, margarine was one of the first hyper-real food products of the modern age.

Trans fats as ‘bad fats’

By the 1980s, food manufacturers and fast-food chains, such as McDonald’s, were being pressured by public health groups to change from using animal fats and tropical oils (such as palm oil) to vegetable oils high in polyunsaturated fats.

But these polyunsaturated-rich oils had also typically been hydrogenated in order to give them the required baking or frying characteristics.

Margarine’s nutritional façade was briefly undermined when a study published in the early 1990s demonstrated that trans fats, in fact, have more harmful effects on blood cholesterol levels than saturated fats.

Other studies have found a number of other associations and more direct harmful properties of trans fats.

Nutrition experts could have paused to question their reductive interpretation of margarine and butter in terms of their fat composition at this juncture, and perhaps reflected more deeply on other characteristics of the dominant nutritional paradigm, such as the good-and-bad fats discourse.

But instead most experts reacted by reasserting and even extending this discourse, by re-categorising trans fats as one of the bad fats and, in fact, as the worst fats of all.

They placed this novel, chemically modified fat in the same “bad fats” basket as saturated fats, thus blurring the distinction between a naturally-occurring and a chemically reconstituted fat.

From trans fats to i-fats

Margarine producers responded by finding new ways of chemically modifying the oils and fats so as to harden them without producing large quantities of trans fats.

They have typically done so by using a combination of the techniques of hydrogenation, fractionation and interesterification — all of which separate and chemically rearrange or transform the fatty acids in vegetable oils.

The end product is no less highly processed and reconstituted. And nutrition scientists don’t really know if these new types of modified fats, which I refer to as i-fats (short for interesterified fats), are any safer than trans fats, since they have not been extensively studied.

Still, these chemical modifications were enough to satisfy most nutrition experts, who seemed content to be told that these reformulated spreads are virtually trans-fat-free.

Many experts have also continued to ignore the underlying processing techniques and additives used in the production of these spreads, maintaining focus on their nutrient composition instead.

While the trans fats fiasco was unfolding in the 1990s, some producers continued to refashion the nutrient profile of their spreads by adding plant sterols (components extracted from plants, such as wood pulp), to produce cholesterol-lowering spreads.

The health claims on these products suggest they actively reduce the risk of heart disease by lowering blood cholesterol levels. But there’s no evidence that consuming the spreads actually reduces the incidence of heart disease.

The resurrection of real butter

Margarines and spreads have also had other fetishised nutrients added to the mix, such as omega-3 fats, in order to claim to nutritional benefits.

In these ways margarine has been taken to the next level of hyper-reality, or what French social theorist Jean Baudrillard referred to as “pure simulation”. Margarine now simulates the nutritional profile of a range of foods.

Its primary reference point is no longer foods, such as butter, because it now almost entirely inhabits of world of nutrients and nutritional concepts.

In some cases butter producers have also chosen to play this nutritional game, by manufacturing reduced-fat varieties, or mixing butter with vegetable oils, such as canola or olive oil, to mimic both the nutritional profile and the spreadability of margarine.

Margarine and spread sales continue to outstrip butter sales. But, despite the continued promotion of margarine by many nutrition experts as a healthy spread, the long-term decline in butter sales has been reversed in recent years in Australia and other countries, while margarine sales are falling.

It may be that many consumers are deciding they prefer the taste and “naturalness” of butter, either because they have discovered the highly processed character of margarine, or because they’re no longer deterred by the vilification of saturated fats.

But this may also be evidence that the ideology of nutritionism itself is beginning to lose its hold, at least on the lay public, as people turn to other ways of understanding and appreciating food quality.

Gyorgy Scrinis is a lecturer in Food and Nutrition Politics and Policy at University of Melbourne. This article was first published on The Conversation.