Diet and nutritionTrans fats—the hidden enemy in cookies and fast food?
- Grażyna Cichosz — Kwasy tłuszczowe izomerii trans w diecie człowieka (Bromatologia i Chemia Toksykologiczna 2012)
- Andrzej Frydrychowski — Czy tłuszcze są nam niezbędne?
- Consumption of industrial and ruminant trans fatty acids and risk of coronary heart disease: a systematic review and meta-analysis of cohort studies. · Eur J Clin Nutr 2011
- Industrially produced trans fat and saturated fat content of food products in Jamaica. · Rev Panam Salud Publica 2023
- Saturated and trans-fatty acids in UK takeaway food. · Int J Food Sci Nutr 2016
- Fast food: unfriendly and unhealthy. · Int J Obes (Lond) 2007
- Assessing trans fat levels in street foods of Tbilisi: a public health concern (2021). · BMC Nutr 2025
- Trans-Fatty Acids in Fast-Food and Intake Assessment for Yerevan's Population, Armenia. · Foods 2022
- Regulation of trans fats: the gap, the Polder, and McDonald's French fries. · Atheroscler Suppl 2006
- Assessing the influence of preconception diet on female fertility: a systematic scoping review of observational studies. · Hum Reprod Update 2023
- Tailoring monoglyceride oleogel crystallization by eutectic and crystal nucleation disturbance: functional frozen specialty fat for use in croissants. · Food Res Int 2026
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Grażyna Cichosz points out that the greatest danger is an excess of artificial trans fats from frying fats and products made with industrially hydrogenated oils.
- They may be found in cakes, cookies, and fast food, and their content varies from product to product.
- Excess industrial trans fats are associated with a higher risk of cardiovascular diseases and some cancers; consumption has also been linked to type 2 diabetes and obesity.
- Grażyna Cichosz distinguishes artificial trans fats from the natural isomers found in the milk and meat of ruminants.
What the authors write
The main dietary sources of trans fats are products made with hydrogenated oils, including confectionery and fast food.
In fast food, cakes, and cookies, TFA make up between 1 and 30% of all fatty acids, and levels vary from product to product.
Artificial trans fats are formed, among other ways, during the hydrogenation of vegetable oils, and products containing them stay fresh longer and are suitable for repeated frying.
The greatest danger is an excess of artificial trans isomers from frying fats and products containing industrially hydrogenated oils.
Excess industrial TFA is associated with changes in blood fat profiles and a higher risk of cardiovascular diseases and some cancers.
Artificial TFA can disrupt the function of cell membranes, and their presence has been linked to the development of some cancers.
Trans fats raise LDL cholesterol and lower HDL cholesterol, worsening the balance between them.
A diet high in artificial TFA may raise LDL and lower HDL, and the study described found these changes after just three weeks.
Consumption of trans isomers has been linked to an increased risk of type 2 diabetes, and excess artificial TFA also contributes to obesity.
Grażyna Cichosz says that harmful effects apply to artificial trans isomers from margarines and convenience foods, and that their amounts in industrial fats should be reduced.
Natural trans isomers occur in the milk and meat of ruminants; Grażyna Cichosz does not identify a health risk when these products are consumed in moderation.
Artificial TFA from hardened oils should not be confused with natural trans isomers from the milk and meat of ruminants.
Andrzej Frydrychowski lists margarines, cookies, sweets, and ready meals as places where the fat in question can be found, and calls it toxic.
Grażyna Cichosz warns that labeling saturated fats and TFA together, without distinguishing between natural and artificial isomers, may mislead consumers.
Research from PubMed · Europe PMC
We selected 9 studies with the best, positive results. This is a selection, not a full review of all research.
Total number of studies on this topic in PubMed: 141.
A meta-analysis found that higher total trans fat consumption was associated with a higher risk of coronary heart disease, while industrial trans fats showed a similar but uncertain trend.
Aim of the study: The aim of this systematic review and meta-analysis was to summarize the evidence from observational studies assessing the association between intake of trans fatty acids (TFA) and the risk of coronary heart disease (CHD), with a specific emphasis on distinguishing between TFA of industrial and ruminant origin.
Results: The pooled relative risk estimates for comparison of extreme quintiles of total-TFA intake (corresponding to intake increments ranging from 2.8 to ∼10 g/day) were 1.22 (95% confidence interval: 1.08-1.38; P=0.002) for CHD events and 1.24 (1.07-1.43; P=0.003) for fatal CHD. Ruminant-TFA intake (increments ranging from 0.5 to 1.9 g/day) was not significantly associated with risk of CHD (risk ratio (RR)=0.92 (0.76-1.11); P=0.36), and neither was industrial-TFA intake, although there was a trend towards a positive association (RR=1.21 (0.97-1.50); P=0.09). In conclusion, our analysis suggests that industrial-TFA may be positively related to CHD, whereas ruminant-TFA is not, but the limited number of available studies prohibits any firm conclusions concerning whether the source of TFA is important. The null association of ruminant-TFA with CHD risk may be due to lower intake levels.
“Not stated” does not mean nobody paid — the database does not always record it.
An analysis of foods in Jamaica found that about one-third of the products tested contained industrial trans fats, including baked goods and burgers.
Aim of the study: To estimate industrially produced trans and saturated fatty acid levels in foods within the Jamaican food system.
Results: Total fat was found to exceed United Kingdom National Health Service (NHS) limits in 27.3% (n = 84/308) of food samples. About one-third (33.8%; n = 104/308) of commonly consumed foods in Jamaica contained varying levels of industrially produced trans fatty acids, while 7.8% exceeded the Pan American Health Organization limit of 2% of total fat. Industrially produced trans fatty acids were found in food categories such as canned meats, baked goods, cooking oils, condiments, breakfast cereals, desserts, dairy, spreads, snacks, and confectionery. The subcategories coconut oils and burgers had the highest mean content. Canned food, infant food, and pasta categories had no trans fat present. Saturated fats were found in almost all foods. Importantly, 32.5% (n = 100/308) of the foods had saturated fat concentrations higher than the NHS limit of 5 g per 100 g of food.
“Not stated” does not mean nobody paid — the database does not always record it.
A study of UK takeaway meals found that some meals exceeded trans fat recommendations in just one serving.
Aim of the study: The aim of the study was to analyze the saturated fatty acid (SFA) and trans-fatty acid (TFA) contents of popular takeaway foods in the UK (including English, pizza, Chinese, Indian and kebab cuisine). Samples of meals were analyzed by an accredited public analyst laboratory for SFA and TFA.
Results: English and Pizza meals had the highest median amount of SFA with 35.7 g/meal; Kebab meals were high in TFA with up to 5.2 g/meal. When compared to UK dietary reference values, some meals exceeded SFA and TFA recommendations from just one meal. Takeaway food would be an obvious target to reduce SFA and TFA contents and increase the potential of meeting UK recommendations. Strategies such as reformulation and smaller takeaway portion sizes warrant investigation.
“Not stated” does not mean nobody paid — the database does not always record it.
Analyses of fast food from many countries found that high levels of industrial trans fats were still present in most of it.
Aim of the study: Although nutrition experts might be able to navigate the menus of fast-food restaurant chains, and based on the nutritional information, compose apparently 'healthy' meals, there are still many reasons why frequent fast-food consumption at most chains is unhealthy and contributes to weight gain, obesity, type 2 diabetes and coronary artery disease.
Results: Chemical analyses of 74 samples of fast-food menus consisting of French fries and fried chicken (nuggets/hot wings) bought in McDonalds and KFC outlets in 35 countries in 2005-2006 showed that the total fat content of the same menu varies from 41 to 65 g at McDonalds and from 42 to 74 g at KFC. In addition, fast food from major chains in most countries still contains unacceptably high levels of industrially produced trans-fatty acids (IP-TFA). IP-TFA have powerful biological effects and may contribute to increased weight gain, abdominal obesity, type 2 diabetes and coronary artery disease. The food quality and portion size need to be improved before it is safe to eat frequently at most fast-food chains.
“Not stated” does not mean nobody paid — the database does not always record it.
Trans fats were found in the street foods tested in Tbilisi, and their amount was higher in servings with more fat and larger portion sizes.
Aim of the study: Industrially produced trans fats (TFA) are associated with significant public health risks, contributing to non-communicable diseases. The World Health Organization (WHO) recommends limiting TFA intake to less than 1% of total energy intake. However, street foods often contain high levels of TFA. Street food is widely consumed in Tbilisi, Georgia, but data on its TFA content is limited.
Results: The mean TFA content was 0.13 g per 100 g of food and 0.31 g per typical serving size provided by the street vendor. Khachapuri (Georgian traditional cheese bread) varieties had the highest TFA levels per portion, significantly differed from other food categories (p < 0.001). Total fat content per portion and portion size were positively associated with TFA levels (r = 0.66, p < 0.01 and r = 0.38, p < 0.01, respectively). Regression analysis showed total fat per portion as a significant predictor of TFA (p < 0.001), explaining 43% of the variance in TFA levels. Although Georgia's regulations set a limit of 2 g of TFA per 100 g of fat, our findings show that some traditional street foods, particularly Khachapuri, may still contribute significantly to TFA intake. While TFA levels were below the regulatory limit, larger portion sizes and frequent consumption could exceed the WHO's daily recommended intake.
“Not stated” does not mean nobody paid — the database does not always record it.
Fast food studied in Yerevan provided trans fats that could increase total intake and exceed the recommended limit when combined with other foods.
Aim of the study: There are stringent regulations applicable for trans-fatty acid (TFA) limitations from food supply across the world. However, in Armenia, there is a scarcity of data on TFA content in food products and their consumption levels.
Results: Mean daily fast-food consumption values ranged from 14.68 g/day to 76.09 g/day, with popcorn as the lowest and pastry as the highest consumed food. The study results indicate that the aggregate average daily intake (DI) of TFA is 0.303 g/day. Even though TFA DI values do not exceed the WHO limit of 1%, they substantially contribute to daily TFA intake and may exceed the limit when combined with other foods. Hence, it is recommended to carry out continuous monitoring of TFA content in the food supply to ensure consumer health protection.
“Not stated” does not mean nobody paid — the database does not always record it.
The described reduction of trans fats in McDonald’s French fries in the Netherlands shows that their content in fast food can be lowered.
Aim of the study: Lowering the intake of trans fatty acids (TFA) probably reduces the incidence of coronary heart disease. Estimates of the reduction vary from 4% based on changes in plasma LDL and HDL concentrations alone, to > 20% based on epidemiological associations when TFA intake is lowered by 2% of energy (5 g/day).
Results: McDonald's French fries in The Netherlands now have less than 4% trans and 24% saturates, as opposed to 21% trans and 21% saturates in the USA. This illustrates the feasibility of reducing TFA in fast foods without increasing saturates. As a result of these developments, dairy and meat have become the major remaining source of TFA in Europe. The question whether these ruminant TFA have the same effect on coronary heart disease risk as industrial TFA has not been settled.
“Not stated” does not mean nobody paid — the database does not always record it.
A review indicated that reducing trans fats may be associated with improved fertility, although the abstract does not give details of this relationship.
Aim of the study: Preconception diet is a proposed modifiable risk factor for infertility. However, there is no official guidance for women in the preconception period as to which dietary approaches may improve fertility.
“Not stated” does not mean nobody paid — the database does not always record it.
The study found that specialty fats without trans fats can be used in croissants to produce a softer product with greater specific volume when butter is partially replaced.
Aim of the study: Oleogels formulated with glycerol monostearate (GMS) emerge as a promising trans-fat-free alternative to conventional plastic fats, yet their practical application in bakery products is impeded by coarse crystalline networks and an undesirable waxy mouthfeel. This study systematically investigated the regulatory impacts of two food-grade crystal modifiers -lecithin (LE) and sucrose ester (SE)- on the crystallization behavior of GMS oleogels.
Results: Notably, SE also enhanced the solid fat content of GMS oleogels but compromised their mechanical strength-a trade-off critical for tailoring oleogel functionality in laminated dough systems. When incorporated into oleogel-based fast-frozen specialty fats (OGSFs), all resultant formulations exhibited refined microstructures, elevated β'-crystal content, and a complete absence of trans fats. In croissant trials, partial substitution (50 %) of butter with OGSFs reduced product hardness, increased specific volume, and improved overall sensory attributes (e.g., texture, mouth-melting property). These findings confirm that LE and SE can effectively modulate GMS oleogel crystallization, thereby providing a viable strategy for developing trans-fat-free specialty fats tailored to the requirements of laminated bakery products.
“Not stated” does not mean nobody paid — the database does not always record it.
Perspectives and opinion materials
The content below presents the authors’ opinions, interpretations and hypotheses. It is not treated as equal to scientific studies and systematic reviews.
Pisaczek does not judge who is right. It shows what was written and where to read it. Every sentence above has its source.