Trans fat
Trans fat is the common name for a type of unsaturated fat with trans isomer fatty acid(s). Trans fats may be monounsaturated or polyunsaturated.
Most trans fats consumed today are industrially created by partially hydrogenating plant oils  a process developed in the early 1900s and first commercialized as Crisco in 1911. The goal of partial hydrogenation is to add hydrogen atoms to unsaturated fats, making them more saturated. These more saturated fats have a higher melting point making them attractive for baking, and extending their shelf-life.  Another particular class of trans fats, vaccenic acid occurs in trace amounts in meat and dairy products from ruminants.
Unlike other dietary fats, trans fats are neither required nor beneficial for health. Eating trans fats increases the risk of coronary heart disease. 
Trans fat raises your ("bad") LDL cholesterol and lowers your ("good") HDL cholesterol. 
Health authorities worldwide recommend that consumption of trans fat be reduced to trace amounts. Trans fats from partially hydrogenated oils are generally considered to be more of a health risk than naturally occurring oils.
Chemically, trans fats are made of the same building blocks as non-trans fats, but have a different arrangement. In trans fatty acid molecules, the hydrogen atoms bonded to pair(s) of doubly bonded carbon atoms (characteristic of all unsaturated fats) are in the trans rather than the cis arrangement. This results in a straight, rather than kinked, shape for the carbon chain, more like the straight chain of a fully saturated fat.

# History
Nobel laureate Paul Sabatier worked in the 1890s to develop the chemistry of hydrogenation which enabled the margarine, oil hydrogenation, and synthetic methanol industries. While Sabatier only considered hydrogenation of vapours, the German chemist Wilhelm Normann showed in 1901 that liquid oils could be hydrogenated, and patented the process in 1902. 
During the years 1905 - 1910 Normann built a fat hardening facility in the Herford company. At the same time the invention was extended to a large scale plant in Warrington, England at Joseph Crosfield & Sons, Limited. It took only two years until the hardened fat could be successfully produced  in the plant in Warrington, commencing production in the autumn of 1909.  The initial year's production was nearly 3000 tonnes. 
In 1909, Procter & Gamble acquired the US rights to the Normann patent; 
in 1911, they began marketing the first hydrogenated shortening, Crisco (composed largely of partially hydrogenated cottonseed oil).  Further success came from the marketing technique of giving away free cookbooks in which every recipe called for Crisco.
Normann's hydrogenation process made it possible to stabilize inexpensive whale oil or fish oil for human consumption, a practice kept secret to avoid consumer distaste.
Production of hydrogenated fats increased steadily until the 1960s as processed vegetable fats replaced animal fats in the US and other western countries.  At first, the argument was a financial one due to lower costs; however, advocates also said that the unsaturated trans fats of margarine were healthier than the saturated fats of butter. The Center for Science in the Public Interest (CSPI) campaigned against the use of saturated fats for fast food cooking starting in 1984.  When fast food companies replaced the saturated fat with partially hydrogenated unsaturated fats, CSPI's campaign against them ended.  While CSPI defended trans fats in their 1987 Nutrition Action newsletter, by 1992 CSPI began to speak against trans fats and is currently strongly against their use.
There were suggestions in the scientific literature as early as 1988 that trans fats could be a cause of the large increase in coronary artery disease. In 1994, it was estimated that trans fats caused 30,000 deaths annually in the US from heart disease.
In January 2007, faced with the prospect of an outright ban on the sale of their product, Crisco was reformulated to meet the US FDA definition of "zero grams trans fats per serving" (that is less than one gram per tablespoon) by boosting the saturation and then cutting the resulting solid with oils. Meanwhile, at the University of Guelph,
Alejandro Marangoni's research group found a way to mix oil, water, monoglycerides and fatty acids to form a "cooking fat" that acts the same way as trans and saturated fats  the stuff that makes baked goods taste so good. The big difference here is Marangoni's process works with "healthier" oils like olive, soybean and canola. He's hoping to get food manufacturers interested in the process this year, as the pressure mounts on the makers of commercial foods to dump trans fats.

# Chemistry
Chemically, fats are large molecules consisting of three fatty acid groups connected to a single glycerol derivative.  The term trans fat generally refers to a fat that contains one or more trans fatty acid groups. Fatty acid molecules are essentially long-chain hydrocarbons with a terminal carboxyl group.  Fatty acids are characterized as saturated or unsaturated based on the number of hydrogen atoms in the acid. If the molecule contains the maximum possible number of hydrogen atoms, it is said to be saturated; otherwise, it is unsaturated to some degree.
Carbon atoms are tetravalent, forming four covalent bonds with other atoms, while hydrogen atoms bond with only one other atom. In saturated fatty acids, each carbon atom is connected to its two neighbour carbon atoms as well as two hydrogen atoms (see structure diagram, below). In unsaturated fatty acids the carbon atoms that are missing a hydrogen atom are joined by double bonds rather than single bonds (see structure graphic below) so that each carbon atom participates in four bonds.
Hydrogenation of an unsaturated fatty acid refers to the addition of hydrogen atoms to the acid, causing double bonds to become single ones as carbon atoms acquire new hydrogen partners (to maintain four bonds per carbon atom). Full hydrogenation results in a molecule containing the maximum amount of hydrogen (in other words the conversion of an unsaturated fatty acid into a saturated one). Partial hydrogenation results in the addition of hydrogen atoms at some of the empty positions, with a corresponding reduction in the number of double bonds. Commercial hydrogenation is typically partial in order to obtain a malleable fat that is solid at room temperature, but melts upon baking (or consumption).
In most naturally occurring unsaturated fatty acids, the hydrogen atoms are on the same side of the double bonds of the carbon chain (cis' configuration  meaning "on the same side" in Latin). However, partial hydrogenation reconfigures most of the double bonds that do not become chemically saturated, twisting them so that the hydrogen atoms end up on different sides of the chain. This type of configuration is called trans, which means "across" in Latin. The trans conformation is the lower energy form, and is favored in the hydrogenation process.
The same molecule, containing the same number of atoms, with a double bond in the same location, can be either a 'trans or a cis fatty acid depending on the conformation of the double bond. For example, oleic acid and elaidic acid are both unsaturated fatty acids with the chemical formula C9H17C9H17O2. They both have a double bond located midway along the carbon chain. It is the conformation of this bond that sets them apart. The conformation has implications for the physical-chemical properties of the molecule. The trans configuration is straighter, while the cis configuration is noticeably kinked as can be seen from the following three-dimensional representation.
The trans fatty acid elaidic acid has different chemical and physical properties owing to the slightly different bond configuration. Notably, it has a much higher melting point, 45 C rather than oleic acid's 13.4 C, due to the ability of the trans molecules to pack more tightly, forming a solid that is more difficult to break apart.  It is notably a solid at human body temperatures.
In food production, the goal is not to simply change the configuration of double bonds while maintaining the same ratios of hydrogen to carbon. Instead, the goal is to decrease the number of double bonds and increase the amount of hydrogen in the fatty acid. This changes the consistency of the fatty acid and makes it less prone to rancidity (in which free radicals attack double bonds). Production of trans fatty acids is therefore a side-effect of partial hydrogenation.
Researchers at the United States Department of Agriculture have investigated whether hydrogenation can be achieved without the side effect of trans fat production. They varied the pressure under which the chemical reaction was conducted  applying 1400 kPa (200 psi) of pressure to soybean oil in a 2 litre vessel while heating it to between 140 C and 170 C.  The standard 140 kPa (20 psi) process of hydrogenation produces a product of about 40% trans fatty acid by weight, compared to about 17% using the high pressure method. Blended with unhydrogenated liquid soybean oil, the high pressure processed oil produced margarine containing 5 to 6% trans fat. Based on current U.S. labelling requirements (see below) the  manufacturer could claim the product was free of trans fat. The level of trans fat may also be altered by modification of the temperature and the length of time during hydrogenation.
Trans fat levels may be measured. Measurement techniques include chromatography (by silver ion chromatography on thin layer chromatography plates, or small high performance liquid chromatography columns of silica gel with bonded phenylsulfonic acid groups whose hydrogen atoms have been exchanged for silver ions). The role of silver lies in its ability to form complexes with unsaturated compounds. Gas chromatography and mid-infrared spectroscopy are other methods in use.

# Presence in food
A type of trans fat occurs naturally in the milk and body fat of ruminants (such as cows and sheep) at a level of 25% of total fat. Natural trans fats, which include conjugated linoleic acid and vaccenic acid, originate in the rumen of these animals.
Animal-based fats were once the only trans fats consumed, but by far the largest amount of trans fat consumed today is created by the processed food industry as a side-effect of partially hydrogenating unsaturated plant fats (generally vegetable oils). These partially hydrogenated fats have displaced natural solid fats and liquid oils in many areas, notably in the fast food, snack food, fried food and baked good industries.
Partially hydrogenated oils have been used in food for many reasons. Partial hydrogenation increases product shelf life and decreases refrigeration requirements. Because baking requires semi-solid fats to suspend solids at room temperature, partially hydrogenated oils can replace the animal fats traditionally used by bakers (such as butter and lard).  They are also an inexpensive alternative to other semi-solid oils such as palm oil. Because partially hydrogenated plant oils can replace animal fats, the resulting products can be consumed (barring other ingredient and preparation violations) by adherents to Kashrut (kosher) and Halal, as well as by adherents to vegetarianism in Buddhism, ahimsa in Jainism and Hinduism, veganism, and other forms of vegetarianism.
Foods containing artificial trans fats formed by partially hydrogenating plant fats may contain up to 45% trans fat compared to their total fat. Baking shortenings generally contain 30% trans fats compared to their total fats, while animal fats from ruminants such as butter contain up to 4%. Those margarines not reformulated to reduce trans fats may contain up to 15% trans fat by weight.
It has been established that trans fats in human milk fluctuate with maternal consumption of trans fat, and that the amount of trans fats in the bloodstream of breastfed infants fluctuates with the amounts found in their milk. Reported percentages of trans fats (compared to total fats) in human milk range from 1% in Spain, 2% in France, 4% in Germany, and 7% in Canada.
Trans fats are also found in shortenings commonly used for deep frying in restaurants. In the past, the decreased rancidity of partially hydrogenated oils meant that they could be reused for a longer time than conventional oils. Recently, however, non-hydrogenated vegetable oils have become available that have lifespans exceeding that of the frying shortenings. As fast food chains routinely use different fats in different locations, trans fat levels in products can have large variation. For example, an analysis of samples of McDonald's french fries collected in 2004 and 2005 found that fries served in New York City contained twice as much trans fat as in Hungary, and 28 times as much trans fat as in Denmark (where trans fats are restricted). At KFC, the pattern was reversed with Hungary's product containing twice the trans fat of the New York product. Even within the US there was variation, with fries in New York containing 30% more trans fat than those from Atlanta.

# Nutritional guidelines
The National Academy of Sciences (NAS) advises the United States and Canadian governments on nutritional science for use in Public policy and product labeling programs. Their 2002 Dietary reference intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids contains their findings and recommendations regarding consumption of trans fat (summary).
Their recommendations are based on two key facts. First, "trans fatty acids are not essential and provide no known benefit to human health", whether of animal or plant origin. Second, while both saturated and trans fats increase levels of LDL cholesterol (so-called bad cholesterol), trans fats also lower levels of HDL cholesterol (good cholesterol); this increases the risk of coronary heart disease (CHD). The NAS is concerned "that dietary trans fatty acids are more deleterious with respect to CHD than saturated fatty acids". This analysis is supported by a 2006 New England Journal of Medicine (NEJM) scientific review that states "from a nutritional standpoint, the consumption of trans fatty acids results in considerable potential harm but no apparent benefit."
Because of these facts and concerns, the NAS has concluded there is no safe level of trans fat consumption. There is no adequate level, recommended daily amount or tolerable upper limit for trans fats. This is because any incremental increase in trans fat intake increases the risk of coronary heart disease.
Despite this concern, the NAS dietary recommendations have not recommended the elimination of trans fat from the diet. This is because trans fat is naturally present in many animal foods in trace quantities, and therefore its removal from ordinary diets might introduce undesirable side effects and nutritional imbalances if proper nutritional planning is not undertaken. The NAS has therefore "recommended that trans fatty acid consumption be as low as possible while consuming a nutritionally adequate diet". Like the NAS, the World Health Organization has tried to balance public health goals with a practical level of trans fat consumption, recommending in 2003 that trans fats be limited to less than 1% of overall energy intake.
The US National Dairy Council has asserted that the trans fats present in animal foods are of a different type than those in partially hydrogenated oils, and do not appear to exhibit the same negative effects. While a recent scientific review agrees with the conclusion (stating that "the sum of the current evidence suggests that the Public health implications of consuming trans fats from ruminant products are relatively limited") it cautions that this may be due to the relatively low consumption of trans fats from animal sources compared to artificial ones. 

# Health risks
Partially hydrogenated vegetable oils have been an increasingly significant part of the human diet for about 100 years (particularly so in the latter half of the 20th century), and some deleterious effects of trans fat consumption are scientifically accepted, forming the basis of the health guidelines discussed above.
The exact biochemical methods by which trans fats produce specific health problems are a topic of continuing research.  The most prevalent theory is that the human lipase enzyme is specific to the cis configuration.  This enzyme can hydrolize the cis double bond, resulting in two lower molecular weight fatty acids that can be further metabolized.  The human lipase enzyme is ineffective with the trans configuration, so trans fat remains in the blood stream for a much longer period of time and is more prone to arterial deposition and subsequent plaque formation.  While the mechanisms through which trans fats contribute to coronary heart disease are fairly well understood, the mechanism for trans fat's effect on diabetes is still under investigation.

## Coronary heart disease
The primary health risk identified for trans fat consumption is an elevated risk of coronary heart disease (CHD). A comprehensive review of studies of trans fats was published in 2006 in the New England Journal of Medicine that concludes that there is a strong and reliable connection between trans fat consumption and CHD.
The major evidence for the effect of trans fat on CHD comes from the Nurses' Health Study (NHS)  a cohort study that has been following 120,000 female nurses since its inception in 1976. In this study, Hu and colleagues analyzed data from 900 coronary events from the NHS population during 14 years of followup. He determined that a nurse's CHD risk roughly doubled (relative risk of 1.94, CI: 1.43 to 2.61) for each 2% increase in trans fat calories consumed (instead of carbohydrate calories). By contrast, it takes more than a 15% increase in saturated fat calories (instead of carbohydrate calories) to produce a similar increase in risk. Eating non-trans unsaturated fats instead of carbohydrates reduces the risk of CHD rather than increasing it. Hu also reports on the benefits of reducing trans fat consumption. Replacing 2% of food energy from trans fat with non-trans unsaturated fats more than halves the risk of CHD (53%). By comparison, replacing a larger 5% of food energy from saturated fat with non-trans unsaturated fats reduces the risk of CHD by 43%.
Another study considered deaths due to CHD, with consumption of trans fats being linked to an increase in mortality, and consumption of polyunsaturated fats being linked to a decrease in mortality.
There are two accepted tests that measure an individual's risk for coronary heart disease, both blood tests. The first considers ratios of two types of cholesterol, the other the amount of a cell-signalling cytokine called C-reactive protein. The ratio test is more accepted, while the cytokine test may be more powerful but is still being studied. The effect of trans fat consumption has been documented on each as follows:
- Cholesterol ratio: This ratio compares the levels of LDL (so-called "bad" cholesterol) to HDL (so-called "good" cholesterol). Trans fat behaves like saturated fat by raising the level of LDL, but unlike saturated fat it has the additional effect of decreasing levels of HDL. The net increase in LDL/HDL ratio with trans fat is approximately double that due to saturated fat. (Higher ratios are worse.) One randomized crossover study published in 2003 comparing the postprandial effect on blood lipids of (relatively) cis and trans fat rich meals showed that cholesteryl ester transfer (CET) was 28% higher after the trans meal than after the cis meal and that lipoprotein concentrations were enriched in apolipoprotein(a) after the trans meals.
- C-reactive protein (CRP): A study of over 700 nurses showed that those in the highest quartile of trans fat consumption had blood levels of CRP that were 73% higher than those in the lowest quartile.

## Other effects
There are suggestions that the negative consequences of trans fat consumption go beyond the cardiovascular risk. In general, there is much less scientific consensus that eating trans fat specifically increases the risk of other chronic health problems:
- Cancer: There is no scientific consensus that consumption of trans fats significantly increases cancer risks across the board. The American Cancer Society states that a relationship between trans fats and cancer "has not been determined." However, one recent study has found connections between trans fat and prostate cancer.
- Diabetes: There is a growing concern that the risk of type 2 diabetes increases with trans fat consumption. However, consensus has not been reached. For example, one study found that risk is higher for those in the highest quartile of trans fat consumption. Another study has found no diabetes risk once other factors such as total fat intake and BMI were accounted for.
- Obesity: Research indicates that trans fat may increase weight gain and abdominal fat, despite a similar caloric intake.  A 6-year experiment revealed that monkeys fed a trans-fat diet gained 7.2% of their body weight, as compared to 1.8% for monkeys on a mono-unsaturated fat diet. Although obesity is frequently linked to trans fat in the popular media, this is generally in the context of eating too many calories; there is no scientific consensus connecting trans fat and obesity.
- Liver Dysfunction: Trans fats are metabolized differently by the liver than other fats and interfere with delta 6 desaturase. Delta 6 desaturase is an enzyme involved in converting essential fatty acids to arachidonic acid and prostaglandins, both of which are important to the functioning of cells.
- Infertility: One 2007 study found, "Each 2% increase in the intake of energy from trans unsaturated fats, as opposed to that from carbohydrates, was associated with a 73% greater risk of ovulatory infertility...".

# Public response and regulation

## International
The international trade in food is standardized in the Codex Alimentarius.  Hydrogenated oils and fats come under the scope of Codex Stan 19.  Non-dairy fat spreads are covered by Codex Stan 256-2007..

## Australia
The Australian federal government has indicated that it wants to actively pursue a policy of reducing trans fats from fast foods. The former federal assistant health minister, Christopher Pyne, asked fast food outlets to reduce their trans fat usage. A draft plan was proposed, with a September 2007 timetable, in order to reduce reliance on trans fats and saturated fats.
Currently, Australia's food labeling laws do not require trans fats to be shown separately from the total fat content.

## Canada
Canada is one of the largest consumers of trans fats in the world. In November 2004, an opposition day motion seeking a ban similar to Denmark's was introduced by Jack Layton of the New Democratic Party, and passed through the House of Commons by an overwhelming 193-73 vote.
Since December 2005, Health Canada has required that food labels list the amount of trans fat in the nutrition facts section for most foods. Products with less than 0.2 grams of trans fat per serving may be labeled as free of trans fats.  These labelling allowances are not widely known, but as an awareness of them develops, controversy over  truthful labelling is growing.  In Canada, trans fat quantities on labels include naturally occurring trans fats from animal sources.
In June 2006, a task force co-chaired by Health Canada and the Heart and Stroke Foundation of Canada recommended a limit of 5% trans fat (of total fat) in all products sold to consumers in Canada (2% for tub margarines and spreads). The amount was selected such that "most of the industrially produced trans fats would be removed from the Canadian diet, and about half of the remaining trans fat intake would be of naturally occurring trans fats". This recommendation has been endorsed by the Canadian Restaurant and Foodservices Association and Food & Consumer Products of Canada has congratulated the task force on the report, although it did not recommend delaying implementation to 2010 as they had previously advocated.
Ten months after submitting their report the Heart and Stroke Foundation of Canada and Toronto Public Health issued a plea to the government of Canada: "to act immediately on the task force's recommendations and to eliminate harmful trans fat from Canada's food supply."
On June 20, 2007, the federal government announced its intention to regulate trans fats to the June 2006 standard unless the food industry voluntarily complied with these limits within two years.

## Denmark
Denmark became the first country to introduce laws strictly regulating the sale of many foods containing trans fats in March 2003, a move which effectively bans partially hydrogenated oils. The limit is 2% of fats and oils destined for human consumption. It should be noted that this restriction is on the ingredients rather than the final products. This regulatory approach has made Denmark the only country in which it is possible to eat "far less" than 1 g of industrially produced trans fats on a daily basis, even with a diet including prepared foods.

## European Union
The European Food Safety Authority was asked to produce a scientific opinion on trans fats.

## United Kingdom
In October 2005, the Food Standards Agency (FSA) asked for better labelling in the UK. In the July 29, 2006 edition of the British Medical Journal, an editorial also called for better labelling. In January 2007, the British Retail Consortium announced that major UK retailers, including ASDA, Boots, Co-op, Iceland, Marks and Spencer, Sainsbury's, Tesco and Waitrose intend to cease adding trans fatty acids to their own products by the end of 2007.
Sainsbury's became the first UK major retailer to ban all trans fat from all their own brand foods.
On 13 December 2007, the Food Standards Agency issued news releases stating that voluntary measures to reduce trans fats in food had already resulted in safe levels of consumer intake.

## United States
Before 2006, consumers in the United States could not directly determine the presence (or quantity) of trans fats in food products.  This information could only be inferred from the ingredient list, notably from the partially hydrogenated ingredients.
On July 11, 2003, the Food and Drug Administration (FDA) issued a regulation requiring manufacturers to list trans fat on the Nutrition Facts panel of foods and some dietary supplements. The new labeling rule allowed for immediate voluntary compliance with mandatory compliance by January 1, 2006 (although companies may petition for an extension to January 1, 2008). The regulation allows trans fat levels of less than 0.5 grams per serving to be labeled as 0 grams per serving. The FDA did not approve nutrient content claims such as "trans fat free" or "low trans fat", as they could not determine a "recommended daily value", however the agency is planning a consumer study to evaluate the consumer understanding of such claims and perhaps consider a regulation allowing their use on packaged foods. The FDA defines trans fats as containing one or more trans linkage that are not in a conjugated system.  This is an important distinction, as it distinguishes non-conjugated synthetic trans fats from naturally occurring fatty acids with conjugated trans double bonds, such as conjugated linoleic acid.
Critics of the plan, including FDA advisor Dr. Carlos Camargo, have expressed concern that the 0.5 gram per serving threshold is too high to refer to a food as free of trans fat. This is because a person eating many servings of a product, or eating multiple products over the course of the day may still consume a significant amount of trans fat. Despite this, the FDA estimates that by 2009, trans fat labeling will have prevented from 600 to 1,200 cases of coronary heart disease and 250 to 500 deaths each year.  This benefit is expected to result from consumers choosing alternative foods lower in trans fats as well as manufacturers reducing the amount of trans fats in their products.
Some US cities are acting to reduce consumption of trans fats. In May 2005, Tiburon, California, became the first American city where all restaurants voluntarily cook with trans fat-free oils. Montgomery County, MD approved a ban on partially hydrogenated oils, becoming the first county in the nation to restrict trans fats.
New York City has embarked on a campaign to reduce consumption of trans fats, noting that heart disease is the primary cause of resident deaths. This has included a Public education campaign (see trans fat pamphlet) and a request to restaurant owners to voluntarily eliminate trans fat from their offerings. Finding that the voluntary program was not successful, New York City's Board of Health has solicited public comments on a proposal to ban artificial trans fats in restaurants. The board voted to ban trans fat in restaurant food on December 5, 2006.  New York is the first large US city to strictly limit trans fats in restaurants.  Restaurants were barred from using most frying and spreading fats containing artificial trans fats above 0.5 g per serving on July 1, 2007, and will have to meet the same target in all of their foods by July 1, 2008.
Philadelphia also recently passed a ban on trans fats. Philadelphia's City Council voted unanimously to pass a ban on February 8, 2007, which was signed into law on February 15, 2007, by Mayor John F. Street. By September 1, 2007, eateries must cease frying food in trans fats. A year later, trans fat must not be used as an ingredient in commercial kitchens. The law does not apply to prepackaged foods sold in the city. On October 10, 2007, the Philadelphia City Council approved the use of trans-fats by small bakeries throughout the city. 
Albany County of New York passed a ban on trans fats. The ban was adopted after a unanimous vote by the county legislature on May 14, 2007. The decision was made after New York City's decision, but no plan has been put into place. Legislators received a letter from Rick J. Sampson, president and CEO of the New York State Restaurant Association, calling on them to "delay any action on this issue until the full impact of the New York City ban is known."
Chicago is also considering a ban on oils containing trans fats for large chain restaurants.
On December 19, 2006, Massachusetts state representative Peter Koutoujian filed the first state level legislation that would ban restaurants from preparing foods with trans fats.  Similarly, Maryland, California, and Vermont are also considering statewide bans of trans fats.
King County of Washington passed a ban on artificial trans fats effective February 1, 2009.
The 2007 Indiana State Fair went to a complete ban on Trans Fats in cooking oils used.

# Food industry response

## Manufacturer response
The J.M. Smucker Company, American manufacturer of Crisco (the original partially hydrogenated vegetable shortening), in 2004 released a new formulation made from solid saturated palm oil cut with soybean oil and sunflower oil. This blend yielded an equivalent shortening much like the previous partially hydrogenated Crisco, and was labelled zero grams of trans fat per 1 tablespoon serving (as compared with 1.5 grams per tablespoon of original Crisco). As of January 24, 2007, Smucker claims that all Crisco shortening products in the US have been reformulated to contain less than one gram of trans fat per serving while keeping saturated fat content less than butter. The separately marketed trans-fat free version introduced in 2004 was discontinued.
On May 22, 2004, Unilever, the corporate descendant of Joseph Crosfield & Sons (the original producer of Wilhelm Normann's hydrogenation hardened oils) announced that they have eliminated transfats from all their margarine products in Canada, including their flagship Becel brand.
Agribusiness giant Bunge Limited, through their Bunge Oils division are now producing and marketing an NH product line of non-hydrogenated oils, margarines and shortenings, made from corn, canola, and soya oils.

## Major users' response
Some major food chains have chosen to remove or reduce trans fats in their products. In some cases these changes have been voluntary. In other cases, however, food vendors have been targeted by legal action that has generated a lot of media attention. In May 2003, BanTransFats.com Inc., a U.S. non-profit corporation, filed a lawsuit against the food manufacturer Kraft Foods in an attempt to force Kraft to remove trans fats from the Oreo cookie.  The lawsuit was withdrawn when Kraft agreed to work on ways to find a substitute for the trans fat in the Oreo.  In November 2006, Arby's announced that by May 2007, it would be eliminating trans fat from its french fries and reducing it in other products.
Similarly, in 2006, the Center for Science in the Public Interest sued KFC over its use of trans fats in fried foods. concerning their class action complaint. KFC reviewed alternative oil options, saying "there are a number of factors to consider including maintaining KFC's unique taste and flavor of Colonel Sanders' Original Recipe". On October 30, 2006, KFC announced that it will replace the partially hydrogenated soybean oil it currently uses with a zero-trans-fat low linolenic soybean oil in all restaurants in the US by April 2007, although its biscuits will still contain trans-fats. Despite the US-specific nature of the lawsuit, KFC is making changes outside of the US as well; in Canada, KFC's brand owner is switching to trans-fat free Canadian canola oil by early 2007. Wendy's announced in June 2006 plans to eliminate trans-fats from 6,300 restaurants in the United States and Canada, starting in August 2006. In November 2006, Taco Bell made a similar announcement, pledging to remove Trans Fat from many of their menu items by switching to canola oil. By April 2007, 15 Taco Bell menu items were completely free of Trans Fat. In January 2007, McDonald's announced they will start phasing out the trans fat in their fries after years of testing and several delays. This can be partially attributed to New York's recent ban, with the company stating they would not be selling a unique oil just for New York customers but would implement a nationwide change.
In response to a May 2007 law suit from the Center for Science in the Public Interest, Burger King announced that its 7,100 US restaurants will begin the switch to zero trans-fat oil by the end of 2007.
The Walt Disney Company announced that they will begin getting rid of trans fats in meals at US theme parks by the end of 2007, and will stop the inclusion of trans fats in licensed or promotional products by 2008.
Health Canada's monitoring program, which tracks the changing amounts of TFA and SFA in fast and prepared foods shows considerable progress in TFA reduction by some industrial users while others lag behind.  In many cases, SFAs are being substituted for the TFAs.