Alice Callahan

Well, this is like the eternal challenge of studying nutrition and health, right? You can observe a large number of people. You can look at how they eat and you can look at what health conditions they develop or whether, you know, they develop obesity. But proving that it's the food that causes those conditions is really challenging, right?

Well, this is like the eternal challenge of studying nutrition and health, right? You can observe a large number of people. You can look at how they eat and you can look at what health conditions they develop or whether, you know, they develop obesity. But proving that it's the food that causes those conditions is really challenging, right?

That's exactly right. Diet is really complicated. And then food is just like one of the things that can affect our health, right?

That's exactly right. Diet is really complicated. And then food is just like one of the things that can affect our health, right?

And you can imagine that people who rely more on ultra-processed foods might also be the same people that are getting less sleep and maybe exercising less or they're under more stress or they're experiencing more poverty or discrimination or less access to healthcare, all of these other factors, right? might contribute to someone's health over the long term.

And you can imagine that people who rely more on ultra-processed foods might also be the same people that are getting less sleep and maybe exercising less or they're under more stress or they're experiencing more poverty or discrimination or less access to healthcare, all of these other factors, right? might contribute to someone's health over the long term.

So, for that, you really need a different kind of study. You need a clinical trial. In a perfect world, you can imagine if you took a large group of people and you randomly divided them into two groups and had one group consuming a diet twice, full of ultra-processed foods and another group consuming a diet full of unprocessed foods.

So, for that, you really need a different kind of study. You need a clinical trial. In a perfect world, you can imagine if you took a large group of people and you randomly divided them into two groups and had one group consuming a diet twice, full of ultra-processed foods and another group consuming a diet full of unprocessed foods.

And you would keep them all living in the same conditions and track them for years and see who develops obesity, who develops type 2 diabetes. That kind of study is obviously really hard to do over the sort of decades that it takes to develop a chronic health condition.

And you would keep them all living in the same conditions and track them for years and see who develops obesity, who develops type 2 diabetes. That kind of study is obviously really hard to do over the sort of decades that it takes to develop a chronic health condition.

That's exactly right. What you can do, though, is a trial kind of like that, but for a much shorter amount of time. And so there was this small study conducted by a researcher named Kevin Hall. And what he did was recruit 20 adults to come and live at the National Institutes of Health for a month. Okay.

That's exactly right. What you can do, though, is a trial kind of like that, but for a much shorter amount of time. And so there was this small study conducted by a researcher named Kevin Hall. And what he did was recruit 20 adults to come and live at the National Institutes of Health for a month. Okay.

And each of those study subjects during their month-long stay at the NIH spent two weeks consuming a diet that was made up of unprocessed foods and two weeks consuming a diet made up of ultra-processed foods.

And each of those study subjects during their month-long stay at the NIH spent two weeks consuming a diet that was made up of unprocessed foods and two weeks consuming a diet made up of ultra-processed foods.

These diets, they were actually very carefully designed by research dietitians so that they were matched in the number of calories on the plate, the amount of carbohydrates, the amount of fat, the amount of sugar, the amount of sodium. So they really wanted to try to isolate this ultra processed factor from the actual nutrition provided in these meals.

These diets, they were actually very carefully designed by research dietitians so that they were matched in the number of calories on the plate, the amount of carbohydrates, the amount of fat, the amount of sugar, the amount of sodium. So they really wanted to try to isolate this ultra processed factor from the actual nutrition provided in these meals.

And they told the study participants that they could consume as much or as little as they wanted of these foods that were placed in front of them. So what happened? What did the study end up finding?

And they told the study participants that they could consume as much or as little as they wanted of these foods that were placed in front of them. So what happened? What did the study end up finding?

Well, I think I should say first, too, that Kevin Hall went into this study thinking that they would find no difference in how much people consumed or whether or not they gained weight during their time at the NIH. Because the diets were so carefully matched for nutrition, he thought that was the thing that really mattered.

Well, I think I should say first, too, that Kevin Hall went into this study thinking that they would find no difference in how much people consumed or whether or not they gained weight during their time at the NIH. Because the diets were so carefully matched for nutrition, he thought that was the thing that really mattered.