The Big Question: What are the properties of trans fats, and should they be banned?

Why are we asking this question now?

The fast-food chain Kentucky Fried Chicken scored a publicity coup in the US on Monday by announcing that it was removing trans fats from the cooking of all but a handful of items on sale in its 5,500 restaurants in the US. Monday, hardly by coincidence, was also the day that public hearings began in New York on a proposed city-wide ban on the fats. The KFC decision is the biggest concession yet by the fast food industry to the growing campaign against trans fats on both sides of the Atlantic that has accelerated since the summer.

New York City announced in September that it would ban all but tiny quantities of trans fats in the food served in its 24,000 restaurants. Under the plans, which are out to consultation until December, all restaurants, cafés and street stalls will be required to limit the trans fats in any item served from their menus to no more than half a gram. Currently one serving of chips can contain up to eight grams.

What are trans fats?

They are produced when liquid oil is turned into solid fat during a high-temperature process called hydrogenation. The method was used a century ago by Procter and Gamble to make a vegetable fat, Crisco, from cottonseed oil, which was cheaper than the lard it replaced and lasted for up to two years at room temperature. It was an immediate hit in US households.

Since then the use of hydrogenated fats has penetrated all sectors of the food industry. It grew in popularity during the two world wars when butter was in short supply and hydrogenated fats were used to make margarine. Hydrogenated fats also mimicked the properties of pork and beef fats so they went into halal, kosher and vegetarian foods. They are found in baked goods, biscuits, snack foods and anything made with or fried in partially hydrogenated oils. Their main selling point is that they are cheap.

What is wrong with them?

Put that another way: what is right with them? According to food experts they have no nutritional value and are an artificial toxic fat that we don't need. The UK Food Standards Agency says they are "harmful and have no known nutritional benefits... They raise the type of cholesterol in the blood that increases the risk of coronary heart disease. Some evidence suggests that the effects of these trans fats may be worse than saturated fats."

Anti trans-fat campaigners put it more colourfully. "Would you melt tupperware and put it on your toast," they ask.

The New England Journal of Medicine, which published a scientific review of trans fats earlier this year, said that "from a nutritional standpoint, the consumption of trans-fatty acids results in considerable potential harm but no apparent benefit." trans fats, like saturated fats, increase levels of LDL cholesterol (so called "bad" cholesterol) but unlike saturated fats also lower levels of HDL cholesterol (good cholesterol).

The British Medical Journal said in a review in July that a 2 per cent rise in our consumption of trans fats - five grams a day - was associated with a 23 per cent increase in the incidence of coronary heart disease. Consumption of trans fats has also been linked with prostate cancer, diabetes, obesity and liver problems, but there is no consensus on these effects.

Which British food products contain trans fats?

trans fats are the hidden fats in Britain, often not listed on food labels. The only way of calculating them is to subtract the sum of the saturated, polyunsaturated and mono-unsaturated fats from the total fats. What is left is the trans fats. So unless you shop with a calculator it is difficult to know how much you are eating.

In the US, since January, food labels have had to state trans-fat quantities. The campaign against them is more advanced there and many products carry banners saying "Now with no trans-fat!" This has fooled some consumers into thinking that products such as ice creams and cakes are fat free when they may contain large amounts of saturated fat. The result has been rising sales. Fast food, pub food and fish and chips don't have to signal the presence of trans fats. Campaigners in the UK argue that there is no pressure to get rid of trans fats because consumers do not know they are there.

What is being done in Britain?

Four British supermarkets - Tesco, Sainsbury's, the Co-op and Asda - have pledged to phase out trans fats from their own-label products. Marks and Spencer and Waitrose have already done so. Kellogs, United Biscuits, Nestlé, Cadbury Schweppes have also promised to reduce or remove trans fats from their products. But Britain has yet to follow Denmark's example which banned trans fats in 2003.

In the US, the burger chain Wendy's has removed trans fats from its french fries and chicken. McDonalds is still using them, though it says it is gradually reducing them. A total ban on trans fats is impractical because they occur naturally in some foods.

A survey by Danish researchers, published in the New England Journal of Medicine in August, found levels of trans fats vary widely, even in identical products. One large serving of chicken nuggets and french fries contained 10 grams of trans fats in New York, 6 grams in the UK, 5 grams in France and 1 gram in Denmark.

Is there any alternative to trans fats?

There is. Under pressure of law suits and legislation, manufacturers have been developing substitute oils and fats. It is this that has persuaded KFC and others to abandon opposition to removing them and concede gracefully. Only in June KFC was still protesting that it had no intention of changing Col Sanders' 50-year-old "finger-lickin' good" recipe. But a new refining process called interesterification has meant that trans fats-containing oils can be replaced at no extra cost.

Unfortuantely, however, some manufacturers are returning to the saturated fats used 20 years ago and abandoned when concern about their link with heart disease was at its height. If that were to occur generally, we would be exchanging one unhealthy food for another.

Should trans fats be banned from all foods in Britain?


* Although they occur naturally in small quantities in a few foods, they are mostly artificially produced and have no nutritional benefits

* They are harmful, increasing the risk of coronary heart disease, and suspected of contributing to other illnesses

* There are safer alternatives available, some of which have been researched and put into use by KFC


* Replacing trans fats with saturated fat would be almost as bad for our health

* Unlike smoking, eating products containing trans fats does not threaten the health of others

* Provided products are properly labelled it should be up to consumers to decide what they eat

Life and Style
A teenager boy wakes up.
Arts and Entertainment
Critics say Kipling showed loathing for India's primitive villagers in The Jungle Book
filmChristopher Walken, Bill Murray, Scarlett Johanssen Idris Elba, Andy Serkis, Benedict Cumberbatch, Cate Blanchett and Christian Bale
Life and Style
food + drink
Life and Style
Playing to win: for Tanith Carey, pictured with Lily, right, and Clio, even simple games had to have an educational purpose
lifeTanith Carey explains what made her take her foot off the gas
Life and Style
Arts and Entertainment
A still from Duncan Campbell's hour-long film 'It for Others'
Turner Prize 2014
Arts and Entertainment
Tony Hadley in a scene from ‘Soul Boys Of The Western World’
musicSpandau Ballet are back together - on stage and screen
Arts and Entertainment
From left to right: Ed Stoppard as Brian Epstein, Sheridan Smith as Cilla Black and Elliott Cowan as George Martin in 'Cilla'
tvCilla review: A poignant ending to mini-series
Life and Style
Bearing up: Sebastian Flyte with his teddy Aloysius in Brideshead Revisited
lifePhilippa Perry explains why a third of students take a bear to uni
Arts and Entertainment
Sir Alan Sugar appearing in a shot from Apprentice which was used in a Cassette Boy mashup
artsA judge will rule if pieces are funny enough to be classed as parodies
ebooksAn unforgettable anthology of contemporary reportage
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Trust Accountant - Kent

NEGOTIABLE: Austen Lloyd: TRUST ACCOUNTANT - KENTIf you are a Chartered Accou...

Geography Teacher

£85 - £120 per day: Randstad Education Cheshire: randstad education are curre...

Teaching Assistant

Negotiable: Randstad Education Group: You must:- Speak English as a first lang...

SEN Teaching Assistant

£17000 - £18000 per annum: Randstad Education Group: If you are a committed Te...

Day In a Page

Isis is an hour from Baghdad, the Iraq army has little chance against it, and air strikes won't help

Isis an hour away from Baghdad -

and with no sign of Iraq army being able to make a successful counter-attack
Turner Prize 2014 is frustratingly timid

Turner Prize 2014 is frustratingly timid

The exhibition nods to rich and potentially brilliant ideas, but steps back
Last chance to see: Half the world’s animals have disappeared over the last 40 years

Last chance to see...

The Earth’s animal wildlife population has halved in 40 years
So here's why teenagers are always grumpy - and it's not what you think

Truth behind teens' grumpiness

Early school hours mess with their biological clocks
Why can no one stop hackers putting celebrities' private photos online?

Hacked photos: the third wave

Why can no one stop hackers putting celebrities' private photos online?
Royal Ballet star dubbed 'Charlize Theron in pointe shoes' takes on Manon

Homegrown ballerina is on the rise

Royal Ballet star Melissa Hamilton is about to tackle the role of Manon
Education, eduction, education? Our growing fascination with what really goes on in school

Education, education, education

TV documentaries filmed in classrooms are now a genre in their own right
It’s reasonable to negotiate with the likes of Isis, so why don’t we do it and save lives?

It’s perfectly reasonable to negotiate with villains like Isis

So why don’t we do it and save some lives?
This man just ran a marathon in under 2 hours 3 minutes. Is a 2-hour race in sight?

Is a sub-2-hour race now within sight?

Dennis Kimetto breaks marathon record
We shall not be moved, say Stratford's single parents fighting eviction

Inside the E15 'occupation'

We shall not be moved, say Stratford single parents
Air strikes alone will fail to stop Isis

Air strikes alone will fail to stop Isis

Talks between all touched by the crisis in Syria and Iraq can achieve as much as the Tornadoes, says Patrick Cockburn
Nadhim Zahawi: From a refugee on welfare to the heart of No 10

Nadhim Zahawi: From a refugee on welfare to the heart of No 10

The Tory MP speaks for the first time about the devastating effect of his father's bankruptcy
Witches: A history of misogyny

Witches: A history of misogyny

The sexist abuse that haunts modern life is nothing new: women have been 'trolled' in art for 500 years
Shona Rhimes interview: Meet the most powerful woman in US television

Meet the most powerful woman in US television

Writer and producer of shows like Grey's Anatomy, Shonda Rhimes now has her own evening of primetime TV – but she’s taking it in her stride
'Before They Pass Away': Endangered communities photographed 'like Kate Moss'

Endangered communities photographed 'like Kate Moss'

Jimmy Nelson travelled the world to photograph 35 threatened tribes in an unashamedly glamorous style