What chemicals are found in fast food?

December 10, 2025 •

4 min read

According to a 2021 study by researchers at George Washington University, over 80% of fast food items tested contained phthalates, a type of chemical used to make plastics more flexible. This discovery highlights a reality that many consumers are unaware of: fast food contains a complex array of chemicals, both intentional additives and unintentional contaminants, that affect flavor, texture, and shelf life.

Quick Summary

Fast food contains numerous intentional and unintentional chemicals, including flavor enhancers like MSG, preservatives such as TBHQ, and plasticizers like phthalates from packaging. These additives impact taste, consistency, and stability, with some linked to potential health concerns.

Key Points

Phthalates and Bisphenols: Fast food often contains plasticizing chemicals like phthalates and bisphenols, which can leach into food from packaging and processing equipment and are linked to hormone disruption.
Preservatives: Synthetic antioxidants like TBHQ, BHA, and BHT are used to prevent fats from spoiling and extend shelf life.
Flavor Enhancers: Chemicals such as MSG, high-fructose corn syrup, and high levels of salt are intentionally added to boost taste and create cravings.
Cooking Byproducts: Harmful compounds like acrylamide (from frying starchy foods) and trans fats can form during the high-temperature cooking process.
Packaging Chemicals: Per- and Polyfluoroalkyl Substances (PFAS) are used in grease-resistant packaging and can contaminate food, potentially leading to health problems.
Health Impacts: Chronic consumption of these chemicals, even in small amounts, is associated with an increased risk of obesity, diabetes, cardiovascular disease, and hormonal issues.
Informed Choices: Consumers can reduce exposure by choosing grilled over fried options, transferring food out of its packaging, and researching nutritional information provided by restaurants.

Common Intentional Additives

To achieve their signature taste, texture, and long shelf life, fast food manufacturers rely on a range of intentional chemical additives. These ingredients are approved for use by regulatory bodies like the FDA but are often a cause for concern among health-conscious consumers. Understanding what these compounds do can help explain the specific characteristics of fast food.

Flavor Enhancers and Sweeteners

Monosodium Glutamate (MSG): A well-known flavor enhancer used to boost the savory, or umami, taste in foods like chicken nuggets, soups, and burgers. It is a form of the amino acid glutamic acid.
High-Fructose Corn Syrup: A common artificial sweetener found in sodas, buns, and sauces. Its overuse has been linked to an increased risk of obesity and type 2 diabetes.
Salt: Used extensively to enhance flavor and create cravings. High sodium content is a defining feature of most fast food items and is a major contributor to high blood pressure and other cardiovascular issues.

Preservatives and Antioxidants

Tertiary Butylhydroquinone (TBHQ): This synthetic antioxidant prevents fats and oils from going rancid, significantly extending the shelf life of items like crackers, chips, and oils used for frying. High doses have been linked to potential health concerns in laboratory animals.
Butylated Hydroxyanisole (BHA) and Butylated Hydroxytoluene (BHT): Closely related to TBHQ, these synthetic antioxidants are used in cereals, processed meats, and snack foods to prevent spoilage.
Sodium Nitrite and Sodium Nitrate: Used in processed meats like hot dogs and bacon to prevent bacterial growth and cure the meat. These chemicals have been linked to an increased risk of stomach cancer.

Other Additives

Caramel Coloring: A widely used food dye that provides the dark brown color to sodas, buns, and sauces. Some forms of caramel coloring contain 4-methylimidazole (4-MEI), which has raised some health concerns.
Emulsifiers and Stabilizers: Ingredients like xanthan gum and propylene glycol are used to improve the texture and consistency of sauces, dressings, and drinks.

Unintentional Chemical Contaminants

Beyond the ingredients listed on the label, fast food items can contain chemicals introduced during processing, cooking, or packaging. These contaminants are not meant to be in the food but can migrate from external sources.

Plasticizing Chemicals: Phthalates and Bisphenols

Phthalates: These chemicals are used to make plastics more flexible and are found in food processing equipment, gloves, and packaging. Studies have shown that phthalates can leach into food, especially those with high-fat content. Phthalate exposure has been linked to hormone disruption and reproductive health issues.
Bisphenols (including BPA): Chemicals like BPA are also present in some food packaging and can migrate into food products. Research has connected BPA to high blood pressure, type 2 diabetes, and cardiovascular disease.

“Forever Chemicals”: PFAS

Per- and Polyfluoroalkyl Substances (PFAS): Often referred to as "forever chemicals," these compounds are used in food packaging, like paper bags and bowls, to resist grease and water. PFAS can move from packaging into the food and have been linked to serious health problems, including some cancers and liver damage.

Cooking-Related Chemicals

Certain compounds form when fast food is prepared, especially at high temperatures.

Acrylamide: A chemical created during high-temperature cooking, such as frying or baking, in starchy foods like French fries. Animal studies have linked high levels of acrylamide to an increased risk of cancer.
Heterocyclic Amines (HCAs): These chemicals form when meat, especially chicken, is cooked at high temperatures. They are known carcinogens and have been detected in grilled fast food products.
Trans Fats: While many companies have reduced or eliminated artificially produced trans fats, they can still be generated when oils are heated to very high temperatures during the frying process. These fats are detrimental to cardiovascular health.

A Comparison of Fast Food Chemical Sources


Chemical Group	Source	Primary Purpose	Potential Health Impact
Intentional Additives	Added directly to food during manufacturing	Enhance flavor, preserve, and alter texture	High sodium linked to high blood pressure; MSG linked to sensitivity reactions; TBHQ linked to tumors in animal studies
Packaging Contaminants	Leaching from plastic packaging and gloves	Not intentional; part of processing and storage	Phthalates and BPA disrupt hormones; PFAS linked to cancer and liver damage
Cooking Byproducts	Formed during high-temperature cooking	N/A (unintended consequence of cooking process)	Acrylamide linked to cancer risk; trans fats harmful to cardiovascular health; HCAs carcinogenic

Navigating Fast Food Choices

It's important to recognize that not all fast food contains the same chemicals or the same levels. Some chains have made commitments to reduce certain additives and replace specific packaging materials. Consumers can take a few steps to make more informed choices:

Read Labels (When Possible): Many fast food chains provide nutritional information on their websites, which can list ingredients and additives.
Choose Fresh Over Fried: Opting for grilled chicken over fried items can significantly reduce exposure to acrylamide and trans fats.
Be Mindful of Packaging: Transferring takeout food out of its packaging promptly can help reduce the migration of chemicals like PFAS and phthalates.

Conclusion

From flavor-enhancing additives to unintentional packaging contaminants, a variety of chemicals can be found in fast food. These substances serve functions like extending shelf life and boosting taste but can also pose potential health risks over time. While the occasional indulgence might be harmless, consistent consumption can lead to cumulative exposure to these chemicals. Understanding what chemicals are found in fast food empowers consumers to make more conscious decisions about their health and diet. The fast food industry continues to evolve, and with greater consumer awareness, there is a push toward more transparent and potentially healthier practices. For more information on health, consider consulting reliable sources like the National Institutes of Health (NIH): https://www.nih.gov/.

Frequently Asked Questions

Phthalates are used to make plastics softer and more pliable. They are found in the gloves used for handling food, as well as in other food processing equipment and packaging. These chemicals can then leach into the food, particularly fatty items.

TBHQ, or Tertiary Butylhydroquinone, is a synthetic antioxidant used to prevent fats and oils from oxidizing and becoming rancid. It is used to extend the shelf life of processed foods like chips, oils for frying, and frozen items.

Chemicals from packaging, such as PFAS and phthalates, can migrate into food, especially when the food is hot or greasy. This transfer can also occur during the manufacturing process from equipment and handling materials.

MSG is a flavor enhancer used to give food a savory taste. While it is generally recognized as safe by regulatory bodies, some individuals report sensitivities to it, experiencing symptoms like headaches or flushing. For most people, it does not pose a significant health risk in typical amounts.

While many chains have reduced artificial trans fats, they can still be formed naturally when oils are repeatedly heated to high temperatures during the deep-frying process. These cooking-induced trans fats are harmful to cardiovascular health.

Forever chemicals, or PFAS, are used in grease-resistant fast food packaging. They are called 'forever' because they do not break down in the environment or the body. They have been linked to serious health concerns, and limiting exposure is recommended.

Yes, acrylamide is a chemical that naturally forms in starchy foods like French fries when they are cooked at high temperatures. High levels have been linked to potential cancer risks in animal studies.