In my family, my passion for bacon is the stuff of legends. I recall a time when I was five years old, eagerly watching my Great Grandma Bess as she cooked breakfast. I would repeatedly exclaim, “I like bacon!” while standing on my tiptoes to get a glimpse of the sizzling bacon turning crispy in the pan. That’s how the family story goes.

My fondness for bacon persists, and I’m certainly not alone in this. Even some of my vegetarian friends carve out an exception for bacon. “Bacon hits all the right notes,” explains Dani Reed, the chief science officer at the Monell Chemical Senses Center in Philadelphia. It starts with the aroma, which captivates almost anyone nearby due to the volatile organic compounds that are released during the frying process. Then, the taste buds get a hit of both salt and sugar, flavors that humans find incredibly tempting. Lastly, the fat content gives bacon a delightful mouthfeel, according to Reed. These three elements combine to make bacon irresistible, even for those who typically avoid pork. Reed describes it as “a ­tsunami of deliciousness.”

However, this irresistible treat is composed of elements that are undeniably harmful to health. In 2015, the World Health Organization classified bacon as a carcinogen. About 40 percent of bacon is saturated fat, a big no-go according to nutrition experts. The nitrates and nitrites used in curing bacon have connections to both hypertension and cancer. During cooking, bacon emits heterocyclic amines and polycyclic aromatic hydrocarbons, which are also cancer-linked substances. Moreover, the salt content in bacon can lead to metabolic issues.

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Lately, nutritional research has pivoted from examining the nutritional content of various foods, like the benefits of whole grains versus the harmful saturated fats in bacon, to focusing more on the level of food processing, particularly foods categorized as “ultraprocessed.”

Using the most widely used classification system, known as NOVA, ultraprocessed foods and beverages contain many industrial additives such as oils, fats, color enhancers, flavor enhancers, artificial sweeteners, and texturizing agents. Examples include soda, potato chips, candy, flavored yogurt, and many commercially available breads. Processed foods are a step down in terms of added ingredients, which are mainly used for preservation or flavor enhancement. Unprocessed foods are simply edible plant and animal parts, perhaps frozen or dried but otherwise unaltered.

Bacon is typically considered a processed food due to added ingredients like salt, sugar, and nitrates. It crosses into the ultraprocessed category when additional flavorings and chemical agents are included. This distinction has raised concerns among nutrition researchers who worry that the public might think eating more bacon and other unhealthy foods is acceptable as long as they are not ultraprocessed. These experts stress that the additives in even simply processed bacon can also pose health risks.

Research comparing the health risks of ultraprocessed versus processed foods is sparse. A 2024 meta-analysis revealed that a higher intake of ultraprocessed foods is linked with increased risks of cardiometabolic diseases, mental health problems, and overall mortality. However, much is still unknown, including a clear consensus on what defines “ultraprocessed.” (The NOVA system is merely a guideline.) Consequently, the team drafting the 2025–2030 Dietary Guidelines for Americans announced in October 2024 that they would not address ultraprocessed foods specifically, opting instead to adhere to current guidelines that recommend nutrient-rich, low-sugar, low-sodium, and low-saturated fat diets.

Julie Hess, a nutrition scientist with the U.S. Department of Agriculture, illustrates how complex the issue of ultraprocessing can be. She and her team designed a seven-day meal plan that aligns with healthy U.S. dietary guidelines but consists largely of ultraprocessed foods. An example breakfast from their plan includes a burrito made with liquid egg whites, shredded cheese, and canned beans. Conversely, they also developed a diet mainly composed of less processed foods but which is overall low in nutrient quality, featuring breakfasts like high-fat, high-sugar pancakes with bacon.

Mingyang Song, a nutritionist and epidemiologist at the Harvard T.H. Chan School of Public Health, advocates for a balanced view on nutrient quality and food processing levels. In a 2024 study, his team categorized foods by their level of processing and then linked them to mortality risks based on consumption rates. They found that high consumption of sugar-sweetened beverages and processed meats correlated with increased mortality risks. However, other ultraprocessed food types like breakfast cereals and commercial breads did not show the same risk. Song notes that maintaining a generally healthy diet can mitigate some negative impacts of consuming ultraprocessed foods.

Kathryn Bradbury, a nutritional epidemiologist from the University of Auckland, warns against getting overly fixated on whether foods are ultraprocessed. She emphasizes that the fundamental guidelines remain relevant: eat more fruits, vegetables, and whole grains while avoiding foods high in calories, saturated fats, sodium, and added sugars. Essentially, it’s better to stick with the basics rather than indulging too often in treats like bacon, which should be enjoyed only occasionally. Unfortunately.

This article provides opinion and analysis, and the views expressed by the author or authors do not necessarily reflect those of Scientific American.