It’s not exactly breaking news that eating whole foods is going to support your body better than relying on a ton of processed foods. But what is making waves in the wellness world is just how much processed foods can screw with your health goals—and how much of them we’re eating. The longest-ever trial of a diet high in ultra-processed foods was just published in the research journal Nature and revealed even more about how processed foods can negatively affect us. Participants who had a diet high in ultra-processed foods had a harder time losing weight than participants who ate minimally processed foods. On the other end of the spectrum, ultra-processed foods contain ingredients that have been manipulated in labs, such as artificial flavors, colors, and preservatives, Dr. Landry says.