If ultra-processed foods really drive weight gain, then giving people a high-calorie,

mostly ultra-processed diet should make them gain weight, right?

And at a glance, this recent study seems to show exactly that,

except that's not really what happened.

Now, I may just be a stickler for details, but let me explain why I think

it's so important to get the details right.

Hello, this is Monica Reinagle, and you are listening to the Nutrition Diva Podcast, a show where we take a closer look at nutrition news, research, and trends to help you make more informed decisions about what you eat.

A recent study of ultra-processed foods seems to be yet another nail in the coffin for so-called UPFs. Media outlets generally presented it as more evidence

that UPFs drive weight gain and have other harmful effects on things like your cholesterol

and your blood pressure. And that, of course, fits perfectly into the prevailing wisdom about

UPFs as the root of all evils. The actual

findings, however, are a little less tidy and a whole lot more interesting. Now, the design of

this study is a little complicated, but in order to understand the larger point that I want to make

here, you really need to understand the setup. So here goes. First of all, the subjects were all

healthy males between the ages of 20 and 35. This is actually pretty typical for university-based

research labs, because universities tend to have a lot of healthy young men lying around.

But, obviously, this sample is hardly representative of the general population.

In any case, these subjects were divided into two main groups.

The young men in the first group were provided with meals that contained enough calories to maintain their current weight.

The fellows in the second group were given meals that provided about 500 extra calories per day.

So all other things being equal, we'd expect those guys to gain around a pound a

week. They then tested two different diets in each of those groups. One diet was very high in

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