Ultraprocessed foods comprise more than half the calories the average American adult eats. They’re also linked to a wide variety of health issues including heart disease, obesity and diabetes. CNN’s Meg Tirrell visits the NIH where researchers are trying to determine why ultraprocessed foods lead to such poor health outcomes and why it’s so hard to stop eating them. #cnn #cnnnews

This is not some kind of spacesuit. It's actually a device used to capture and study the air Sam, who you see here, is breathing out. He's participating in a study at the National Institutes of Health, measuring the effects of ultra-processed foods on the body. We have this huge category of ultra-processed foods. What we're trying to understand is what are the mechanisms? What is it about this category of foods that is driving people to over-consume calories, potentially leading to obesity and these downstream consequences? This is one of the only trials like this that's really ever been done. They are trying to understand the effects of different kinds of food on the human body. But it's really difficult to run these kinds of trials because you have to have such a controlled environment. Sam is living here for a month. He's been here for two weeks already. He's got two more weeks to go. While people are here, the main outcome that we're interested in is how many calories they choose to eat. And so we're measuring things like their glucose levels over the course of the day. We're measuring how hungry and full and satisfied people feel. We're measuring how quickly they're eating their meals. We're measuring how they're moving. Researchers also want to know how ultra-processed foods affect metabolism and weight gain. That's the reason for the breathing apparatus like this one. When we burn calories in the body, it's just like burning firewood or something like that. It's combusting energy, but it's happening very slowly. And so we can measure how many calories someone's burning by measuring how much air they're using up, how much oxygen they're using up, and how much carbon dioxide they're producing.