Ultra-processed foods - such as chicken nuggets, ice cream and breakfast cereals - have been linked to early death and poor health, scientists say.
Researchers in France and Spain say the amount of such food being eaten has soared.
What are ultra-processed foods?
The term comes from a way of classifying food by how much industrial processing it has been through.
The lowest category is “unprocessed or minimally processed foods”, which include: fruit, vegetables, milk, meat, legumes, grains such as rice, eggs.
“Processed foods” have been altered to make them last longer or taste better - generally using salt, oil, sugar or fermentation.
This category includes: cheese, bacon, home-made bread, tinned fruit and vegetables, smoked fish, beer.
Then come “ultra-processed foods”, which have been through more substantial industrial processing and often have long ingredient lists on the packet, including added preservatives, sweeteners or color enhancers.
Prof Maira Bes-Rastrollo, from the University of Navarra, told BBC News: “It is said that if a product contains more than five ingredients, it is probably ultra-processed.”
Examples include: processed meat such as sausages and hamburgers, breakfast cereals or cereal bars, instant soups, sugary fizzy drinks, chicken nuggets, cake, chocolate, ice cream, mass-produced bread, many “ready to heat” meals such as pies and pizza, meal-replacement shakes.
The first study, by the University of Navarra, in Spain, followed 19,899 people for a decade and assessed their diet every other year.
There were 335 deaths during the study.
But for every 10 deaths among those eating the least ultra-processed food, there were 16 deaths among those eating the most (more than four portions a day).
The second study, by the University of Paris, followed 105,159 people for five years and assessed their diet twice a year.
It showed those eating more ultra-processed food had worse heart health.
Rates of cardiovascular disease were 277 per 100,000 people per year among those eating the most ultra-processed food, compared with 242 per 100,000 among those eating the least.
Dr Mathilde Touvier, from the University of Paris, told BBC News: “[The] evidence is accumulating.”
“Increasing numbers of independent studies observe associations between ultra-processed foods and adverse health effects.”
Last year, a link was made with an increased risk of cancer.
Prof Bes-Rastrollo, from the University of Navarra, told BBC News she was “very certain” they were bad for health.
The first trial of ultra-processed foods showed they led people to eat more and put on weight.
Researchers at the US National Institutes of Health monitored every morsel of food that volunteers ate for a month.
And when given ultra-processed food, they ate 500 calories a day more than when they were given unprocessed meals.
The studies were published in the British Medical Journal.