Does fake meat cause heart disease? Here's what the science actually says.

Recent headlines denounced plant-based fake meat — such as vegetarian sausages and textured vegetable protein — as unHealthy and claimed that their consumption is linked to an increased risk of cardiovascular disease and death. But a closer look at the study underpinning these claims suggests a more nuanced story.

The real culprits are in fact "plant-based" ultraprocessed foods as a whole, not meat substitutes in particular, according to the paper that kickstarted the headlines. But there's an important caveat: "plant-based" foods include ones you might not expect — such as chocolate-covered biscuits, frozen pizza and sodas. The study, published earlier this month in the Lancet Regional Health–Europe, linked plant-based ultraprocessed foods to an increased risk of cardiovascular-related illnesses and death.

Plant-based meat represented a very small slice of study participants' overall food consumption, however, and the study was not designed to pinpoint exactly which foods had the strongest links to poor health outcomes. Nevertheless, the muddled interpretations show just how complex nutrition research can be, critics say, because food definitions used by scientists don't always reflect what other people might interpret as a plant-based diet.

Foods are described as ultraprocessed when they undergo an industrial transformation that significantly alters the original ingredients. These foods have a long journey before reaching your plate. Pantry staples such as instant noodles and store-bought cookies typically undergo several stages of processing that unravel the internal architecture of their raw ingredients. They are then reassembled in a form that prioritizes convenience and taste — often with a mix of additives designed to enhance appearance and shelf life. A rule of thumb is to "think of a food you wouldn't be able to prepare in your own kitchen," either because of its chemical constituents or the industrial machinery needed to prepare it, says Evangeline Mantzioris, a researcher and dietician at the University of South Australia, who was not involved with the study.

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In nutrition research, including in this widely discussed paper, a framework known as the NOVA classification system is used as a benchmark to group foods along a spectrum from unprocessed to ultraprocessed based on the level of alteration from their natural state. Most foods can be categorized intuitively. Broccoli or beans are not considered ultraprocessed, whereas breakfast cereals and canned soups are. Others might not be obvious at first glance, however. For example, the new Lancet Regional Health–Europe study included beer and wine as examples of non-ultraprocessed beverages, but spirits such as vodka were considered ultraprocessed.

The idea behind using this framework in food research is that processing food might fundamentally change how it interacts with the body to iNFLuence Health, says Fernanda Rauber, lead author of the new study and a nutritional epidemiologist at the University of São Paulo in Brazil. The Health effects of food aren't "just from the sum of its nutrient functions," she says. "The way foods are combined, prepared and consumed as meals also plays a crucial role in their Health impacts."