Plant-based diets have long been promoted as a gold standard for heart health, praised for their high fibre content, abundance of vitamins, and lower levels of saturated fat compared with meat-heavy eating patterns. But striking new research suggests that not all plant-based foods are created equal and that relying heavily on ultra-processed vegan meals could actually increase the risk of heart disease rather than reduce it.
A major study published in The Lancet has found that people who consume large amounts of ultra-processed plant-based foods face a significantly higher risk of developing cardiovascular disease, including coronary heart disease and heart attacks. The findings raise concerns about the growing popularity of plant-based ready meals, meat substitutes, and packaged vegan products that are often marketed as healthy alternatives.
The research followed more than 63,800 middle-aged adults in France over nearly a decade, tracking their diets, lifestyle habits, and long-term health outcomes. While participants who ate diets rich in whole, minimally processed plant foods saw substantial heart-protective benefits, those whose plant-based diets were dominated by ultra-processed foods experienced sharply worse cardiovascular outcomes.
According to the study’s lead author, Clémentine Prioux, a nutrition researcher at Sorbonne University, the results challenge the idea that simply removing animal products from the diet is enough to protect heart health.
“Our findings reinforce the need to focus not only on reducing animal products,” she explained, “but also on encouraging the consumption of minimally processed plant-based foods. Processing appears to play a critical role in determining whether a diet is beneficial or harmful for cardiovascular health.”
A Stark Divide Between Whole Foods and Ultra-Processed Alternatives
Over an average follow-up period of just over nine years, the researchers found that participants who followed a nutritionally balanced, largely unprocessed plant-based diet were 44 per cent less likely to develop coronary heart disease. This includes conditions such as angina, heart attacks, and heart failure.
In sharp contrast, individuals who relied heavily on ultra-processed plant-based foods faced a 46 per cent higher risk of coronary heart disease and a 38 per cent increased risk of cardiovascular disease overall. Cardiovascular disease is an umbrella term that includes heart attacks, strokes, and other disorders affecting the heart and blood vessels.
These less healthy plant-based diets tended to include large amounts of supermarket bread, packaged soups, ready-made pasta dishes, processed meat substitutes, and pre-prepared salads loaded with creamy dressings. Many of these products contain industrial additives such as emulsifiers, stabilisers, flavour enhancers, and preservatives ingredients rarely found in home cooking.
While such foods may carry vegan or plant-based labels, they are often high in salt, unhealthy fats, and refined carbohydrates, while being low in fibre and essential micronutrients.
Processing Matters More Than Plant Versus Animal Foods
One of the study’s most striking findings was that people who consumed some animal products but avoided ultra-processed foods—were no more likely to develop heart disease than those following healthy, whole-food plant-based diets.
This suggests that food quality and the degree of processing may be more important for heart health than whether a diet is strictly plant-based or includes animal products.
The data were drawn from the French NutriNet-Santé study, one of the largest and most detailed nutrition studies in Europe. Participants regularly completed comprehensive health questionnaires and provided repeated 24-hour dietary records, which captured everything they ate and drank, including snacks.
Portion sizes were estimated using photographs and standardised containers, while nutrient intake was calculated using a validated food composition database and verified through blood and urine biomarkers. Researchers also adjusted for key lifestyle factors such as smoking, physical activity, body weight, and socioeconomic status.
How Foods Were Classified
To analyse the impact of food processing, researchers used the NOVA classification system, which groups foods according to how they are made rather than simply their nutrient content.
Under this system, unprocessed or minimally processed foods include fruits, vegetables, grains, legumes, nuts, pasta, and fresh or frozen meat and fish foods altered only through basic methods such as freezing, drying, or pasteurisation.
Processed foods are created by adding ingredients like salt, sugar, or oil to whole foods, such as cheese, freshly baked bread, or canned vegetables.
Ultra-processed foods, however, are industrial formulations produced through multiple processing steps. They often contain additives such as artificial sweeteners, flavourings, colourings, and preservatives, and are designed to be highly palatable, long-lasting, and convenient.
These products are typically energy-dense, high in added sugar and saturated fat, and low in fibre traits strongly linked to heart disease.
Implications for the UK and Beyond
The researchers warned that their findings may be especially relevant to countries like the UK, where the market for ultra-processed plant-based products is particularly large. Previous studies suggest that people in the UK consume roughly twice as many ultra-processed plant-based foods as those in some other European nations.
This comes at a time when NHS data shows a worrying rise in heart attacks among younger adults. Over the past decade, the largest percentage increase has been recorded among people aged 25 to 29, although experts note that small absolute numbers can exaggerate percentage changes.
Still, doctors and public health officials are increasingly concerned that poor diet quality, rising obesity rates, and heavy consumption of processed foods may be contributing to earlier onset cardiovascular disease.
Not a Green Light for Processed Meat
Importantly, the researchers stressed that ultra-processed animal-based foods were associated with an even higher risk of heart disease than their plant-based counterparts. In other words, swapping ultra-processed vegan burgers for ultra-processed meat products is unlikely to improve health outcomes.
Instead, the study highlights the importance of evaluating diets across three key dimensions: the balance between plant and animal foods, the nutritional quality of those foods, and the degree to which they are processed.
“Our results show that plant-based diets are not inherently protective,” the authors concluded. “The level of processing can significantly alter their association with cardiovascular disease.”
A Reminder That ‘Plant-Based’ Does Not Always Mean Healthy
Heart disease remains one of the leading causes of death and disability in the UK and worldwide. It is commonly caused by a build-up of fatty deposits in the arteries, which restrict blood flow and increase the risk of dangerous blood clots.
Experts agree that many cases could be prevented through healthier eating patterns, regular exercise, and avoiding smoking. But this study serves as a timely reminder that dietary labels can be misleading.
While plant-based eating can offer powerful health benefits, those advantages appear to vanish and may even reverse when whole foods are replaced with highly processed alternatives.
As ultra-processed foods continue to dominate supermarket shelves, researchers and health experts are increasingly calling for clearer guidance that prioritises food quality over marketing claims, encouraging people to base their diets on simple, minimally processed ingredients wherever possible.