According to a group of French scientists who've studied the diets of more than 100,000 people, eating highly-processed (or ultra-processed) food puts people at a higher risk of developing cancer.
Ultra-processed foods contain artificial ingredients designed to keep them fresh on shop shelves and to make them more appetising. These include ready meals, cakes, mass-produced bread and instant noodles.
Al Jazeera's Neave Barker reports from London.