With increasingly more people opting for plant-based diets – whether it’s for health, environmental, or ethical concerns –  a new study has highlighted that switching to vegetarianism may entail an undesirable side effect: eating more ultra-processed foods.

In a new study, scientists looked at the consumption of ultra-processed food, plus “minimally processed food” across nearly 200,000 people who have participated in the UK Biobank project.

They found vegetarians ate more ultra-processed food (by around 1.3 percentage points) compared to regular red meat eaters. Vegans also ate slightly more ultra-processed food compared to regular red meat eaters, although the disparity was not significantly different (1.2 percentage points).

The study concludes: “This UK-based study found higher UPF [ultra-processed food] consumption in vegetarian diets and lower in diets with a modest amount of meat or fish.”

“It is important that policies which encourage the urgently needed transition to more sustainable dietary patterns also promote rebalancing diets towards minimally processed foods,” it adds. 

Here lies the problem: many people eating plant-based diets in the industrialized world don’t solely eat a balanced variety of fresh vegetables and fruits. When trying to avoid meat, well-intentioned consumers can also opt for meat substitutes, prepared ready meals, and other “convenience foods” that are often loaded with more calories, saturated fat, salt, sugar, and all kinds of additives. 

It’s becoming evident that eating this kind of stuff has the potential to negatively impact your health. A previous study found that eating large amounts of plant-based ultra-processed foods may pose a higher risk of cardiovascular diseases compared to less-processed plant-based foods. 

Bear in mind, though, that this is a complex debate.

It’s fairly hard to define what constitutes “ultra-processed foods”. While there is a widely used classification system – NOVA, which categorizes foods based on how they are made – the boundaries of what counts as “ultra-processed” can still be subjective and debated among experts.

Under the NOVA classifications, ultra-processed foods are “industrial formulations made entirely or mostly from substances extracted from foods (oils, fats, sugar, starch, and proteins), derived from food constituents (hydrogenated fats and modified starch), or synthesized in laboratories from food substrates or other organic sources (flavor enhancers, colors, and several food additives used to make the product hyper-palatable).” 

In other words, it often includes food like frozen pizza, instant noodles, pre-packaged burgers, hot dogs, candy bars, sweetened breakfast cereals, sugary soda, and so on. These types of food go through numerous layers of processing and tend to gather other additives to keep them fresher, boost their flavor, or make them look more appealing. 

None of this is to say that plant-based diets are inherently unhealthy; on the contrary, studies have suggested that eating a well-planned vegan diet may reduce the risk of chronic diseases, such as type 2 diabetes, hypertension, and certain types of cancer.

Likewise, a broad range of studies have shown a clear link between a high intake of red meat and a higher risk for heart disease, cancer, diabetes, and even premature death. Then again, some research has suggested that the problem with consuming red meat is more strongly associated with eating highly processed stuff as opposed to high-quality, unprocessed meat.

The key message is that ultra-processed foods are generally unlikely to be beneficial for your health, even though the definitions can be somewhat ambiguous. This remains true whether the processed food is plant-based or meat-based. If you’re choosing a plant-based diet, it’s important to be mindful that it’s easy to overindulge in processed foods, rather than focusing on fresh, whole foods that are typically healthier.

The new study is published in the journal eClincalMedicine.

The content of this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions.