Westernized foods have become an important source of diet among a significant portion of urban residents in China at present. Cookies, ice cream and hamburgers have even become the main source of calories for some children and teenagers, unknowingly consuming large amounts of health-hazardous trans fatty acids. Trans fatty acids are unsaturated fatty acids containing trans double bonds, especially in hydrogenated vegetable oils, which are extremely high in content, accounting for 10%-60%. Trans fatty acids are not good for health. It increases “bad cholesterol” and lowers “good cholesterol. Because of the advantages of high melting point, good flavor, good taste, easy preservation and low cost, hydrogenated fats are widely used in the production of cakes, creams, cookies, French fries and other foods. As a result, TFA are hidden in margarine, shortening and frying oil flowing to food processing plants and restaurants, being made into cookies, bread, candy, cakes, all kinds of moon cakes, coffee mates, fried chicken, etc., and entering our bodies and blood in large quantities, seriously damaging our health. Trans fatty acids can destroy the integrity of vascular endothelial cells, increase the risk of morbidity and mortality of coronary heart disease, diabetes, prostate cancer, gallstones, and more seriously, also affect the growth and development of infants through breast milk, and also affect the appetite of children. China’s food hygiene academic circles, including government departments, are now quite behind in their understanding of TFA, and most people, including catering personnel, lack awareness. We hope that the relevant departments will urgently develop standards and routine testing methods for TFA content in food and make it mandatory to calibrate the content in key foods. Parents should not allow their children to eat this kind of “junk food”, and they had better stay away from this kind of substandard food.