Even if we think we have the driver of the UPF effects on energy intake more figured out in adults, we can't assume the same for every part of development.
That's what's important. In population studies, adolescents consume the most UPF. They are worth studying.

Yes, when you obsessively nutrient match as we did you don't see meaningful differences *in adults.*
The reason we highlight something might be different in younger people is developmental biology is often ignored or children/adolescents treated as small adults.

"As an exploratory analysis we propose to specify a mixed-effects ANOVA, a class of mixed models. Energy intake will be regressed on dummy-coded UPF and Non-UPF conditions as the reference category, and fixed effects for relevant biological variables (e.g., age, sex) and experimental variables such as diet order." From the trial registration

We say it's exploratory in the registration and say it's exploratory in the paper.
I agree, the group cut off is probably meaningless. Biology doesn't work like that.
The linear relationship reported, thpugh, makes me think something is different about younger people that we need to understand.

Knowing if different mechanisms are at work in different age groups, especially young people who have high UPF intake and are still developing, is worth exploring.

Age, sex, and BMI were the randomization factors for our RCT. So, it's reasonable to test an interaction term with them.
The study was powered for fMRI outcomes (which are being written up).
For the intake results (pictured above), we were powered at n=13. 11 is still less, yes, by two people.

Orange tabby being petted by hand with splinted pinkie finger.

1. Keep you fingers out of car doors.
2. Pet your cat.

Booo. You’ll get the next one.

Thank you!

This work was lead by Zach Hutelin and done at the @fbri-chbr.bsky.social @fralinbiomed.bsky.social at @virginiatech.bsky.social.
And NIH FUNDED.

I guess my point is that processing is changing foods in ways we aren't expecting.
If everything we know should remain unchanged, foods matched on every nutritional property shouldn't evoke distinct metabolic and neural profiles.
So, we need to update how we are thinking and catch up. /15

People change on evolutionary timescales, we are similarly complex now as we were 100 years ago.
But, food is MUCH more complex.
Food science and technology is way ahead of those of us trying to understand what happens when you put that food into the insane bioreactor that is a human body. /14

This is where the info on the nutrition facts label comes from.
We have always known the human body is not a bomb calorimeter but an extremely complex peice of biochemistry that is interacting with food substrates in amazingly complex ways. /13

What does it all MEAN!?! I'd love to know what other people think.
But, right now where I'm sitting is this: Atwater published his conversion factors in the 1890's. This is where we get 4kcal/g carb, 9kcal/g fat, etc. This was updated by Merrill and Watt in the 1950's and again in the 1970's. /12

But, if we look at how the brain is encoding that value, we see a pattern where brain response is positively correlated with value for nonUPF but negative for UPF in areas of visual cortex and the striatum. /11

In an auction task, we see people do not pay more for UPFs vs nonUPFs. We hypothesized they would. This was a surprise, but we looked into the brain anyway. /10

But can the brain pick up on this metabolic difference?
It seems like yes.
Using a measure of food cue reactivity, we see that RER and carbohydrate oxidation correlate with brain response in the ventral striatum and caudate. /9

Your ability to do that is known as metabolic flexibility and it's impaired in people with obesity and metabolic disease. Our participants are fasted until we feed them, so we expect a rapid shift to carbohydrate oxidation, which we see after the nonUPF meal, but it's blunted after the UPF meal. /8

Looking at those data every single measure was different.
Respitory exchange ratio let's us know if you are burning carbohydrates or fat.
After eating you should switch quickly to using the carbohydrates in your food (higher numbers) and when you are fasted, you switch to fat oxidation. /7

Now the chamber data.
A metabolic chamber is a super fancy sealed room hooked up to a gas analyzer that will make you question every life decision that lead you to the point of being in charge of one.
But when it works it's minute by minute data on metabolic rate and substrate oxidation. /6

The core told me not to tell your grandmother how to knit (nicely), but the results were what they were.
I was so surprised becuase more insulin for the same amount of glucose control is what you see in insulin resistance. /5

Blood glucose was similar (matched GI and GL) the curve is right shifted, but not crazy.
Then, we got insulin back from the core.
We plotted the data and then I called them to make sure they didn't mess something up. Insulin was hugely elevated after the UPF meal (in the same people!). /4

"This seems like a lot of work for a null result" is what my grad student said to me at the start of this project. I agreed, we matched on so many factors, but it was important to see if anything was different. It should be the same doesn't cut it.
But, then we started getting the data. /3

image of a timeline and two meals one UPF and one nonUPF

To examine the postingestive metabolic effects, we put participants in a metabolic chamber and fed them two meals counterbalanced across days. These meals differed on Nova score (1-3 vs 4), but were matched within 1% on nutrition (including glycemic index and load!).

One hypothesis is as to "HOW?" is that UPF have unexpected metabolic effects compared to nonUPF.

This is important since this could lead both to their metabolic health effects and, becuase your brain learns about food from your metabolic response, it could lead to over-valuation of these foods. /2

New preprint from the lab🧵🧪 Eating ultraprocessed foods leads to poor health outcomes, but HOW they do it isn't understood. "HOW?" is important, as "how" can allow targeted policy, reformulaiton, or recommendations to reduce harmful effects. We started to ask that question doi.org/10.64898/202...

I’ve seen an uptick in kids from northern VA schools and I’m way out in Roanoke.

Reminds me of my other favorite Ursula: “Freedom is a heavy load, a great and strange burden for the spirit to undertake. It is not easy. It is not a gift given, but a choice made, and the choice may be a hard one”
I always come back to it’s a choice made. As you said, it’s work.

I’d say it if someone were missing an event, even if they weren’t apologizing, as a polite way to respond. “You’ll be missed” sounds ominous, “next time” is acceptable, but “don’t worry about it” is a nice way to say your presence wasn’t required and it’ll be fine without you.

Just got this email from my SRO. That was my first thought. That they’re trying to make panels unfillable so it’s another excuse to not fund grants.