# Ultra-processed diets mean you eat more



## Eddy Edson (Jul 16, 2019)

https://www.sciencedirect.com/science/article/pii/S1550413119302487

Eating ultra-processed food means you eat more.

(No, it's not "obvious": this is the first rigorous RCT to study the comparison in a group eating ad libitum. And no, the study size isn't "too small".)







_Increased availability and consumption of ultra-processed foods have been associated with rising obesity prevalence, but scientists have not yet demonstrated that ultra-processed food causes obesity or adverse health outcomes. Researchers at the NIH investigated whether people ate more calories when exposed to a diet composed of ultra-processed foods compared with a diet composed of unprocessed foods. Despite the ultra-processed and unprocessed diets being matched for daily presented calories, sugar, fat, fiber, and macronutrients, people consumed more calories when exposed to the ultra-processed diet as compared to the unprocessed diet. Furthermore, people gained weight on the ultra-processed diet and lost weight on the unprocessed diet. Limiting consumption of ultra-processed food may be an effective strategy for obesity prevention and treatment.

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... metabolizable energy intake was 508 ± 106 kcal/day greater during the ultra-processed diet (p = 0.0001). Neither the order of the diet assignment (p = 0.75) nor sex (p = 0.28) had significant effects on the energy intake differences between the diets. Baseline BMI was not significantly correlated with the energy intake differences between the diets (r = 0.11; p = 0.66).

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The increased energy intake during the ultra-processed diet resulted from consuming greater quantities of carbohydrate (280 ± 54 kcal/day; p < 0.0001) and fat (230 ± 53 kcal/day; p = 0.0004), but not protein (−2 ± 12 kcal/day; p = 0.85) 

....

Whereas sodium intake was significantly increased during the ultra-processed versus the unprocessed diet (5.8 ± 0.2 g/day versus 4.6 ± 0.2 g/day; p < 0.0001), there were no significant differences in consumption of total fiber (48.5 ± 2.3 g/day versus 45.8 ± 2.3 g/day; p = 0.41) or total sugars (93.3 ± 4.0 g/day versus 96.6 ± 4.0 g/day; p = 0.57).
_
Lead investigator Kevin D. Hall heads up obesity etc research at the NIDDK. His group produced my favourite body weight planner https://www.niddk.nih.gov/bwp based on research described in this really excellent paper: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3880593/pdf/nihms539778.pdf

He has an interesting take on the causes of the "obesity epidemic": Nixon-era farm subsidies. Farmers were clamouring for relief; congress and the USDA responded with corn, soy etc subsidies leading to a flood of cheap ingredients available to be processed into tasty crap. As he says, USDA etc officials who grew up in the Depression were not likely to factor in the risk of an "obesity epidemic".

He quantifies the problem in rough terms: an average energy imbalance of about 25 cal/day, leading over the last 30 years to weight increase equivalent to about 200 extra cal/day for weight maintenance at the higher levels, compared to the 1970's.


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## Eddy Edson (Sep 10, 2019)

Kevin Halls' presentation this paper at a recent meeting: https://ondemand.nutrition.org/s/2019an/annual/ASN19-62

He makes it clear that he went into the study dubious about the hypothesis that ultraprocessed => weight gain. If the nutrients are the same, why any difference? So he was surprised & fascinated by the results.

In terms of "why", the most obvious factor coming out of the study was this:






People ate ultraprocessed food much more quickly. But the study didn't reveal any differences in palatability, satisfaction etc etc - so this just pushes the "why" question back a step.

Anyway, as with most good science, more questions are raised than answered:







He's very skeptical about simple-minded policy moves, including any form of ultra-processed food tax, which he thinks would be stupidly regressive:






And he thinks that just maybe the answer is *better* processing, once the mechanisms are understood better. But you would need to look beyond the normal suspects:






He's my favourite diet science bod at the moment. Every nutrition guru-wannabe seems to hate him, he asks more questions than he pretends to have answers to, and he doesn't sell anything.


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## Eddy Edson (Sep 13, 2019)

Hall's presentation the other day at an NIH session: https://videocast.nih.gov/summary.asp?Live=34719&bhcp=1 at around the 1.30 mark.

- Nicely presenting all of the rigorous study work his NIH lab has done over the last few years showing absolutely zero evidence in support of the "carbohydrate insulin obesity" hypothesis - ie the various modern descendants of Atkins woo including keto etc etc. Low carb diets and low fat diets have no meaningful difference in body weight outcomes under rigorously controlled conditions, at least in the shorter term (but with zero reason to expect anything different if you extended out further).  Low carb => lower insulin => more fat burning, as advertised; but this does no more than balance out the extra fat eaten.  Energy expenditure actually goes down a bit with low carb.

"It's carbs not calories" seems to be simply incorrect when it comes to weight loss.

- Presenting a quick overview of his lab's previous work on calorie reduction and weight loss. Short version: as you lose weight your hunger increases much more rapidly than your calorie reduction.  So the level of effort required to *maintain* a particular level of weight loss can be just as great as the effort required to lose the weight in the first place. Hence - plateauing & weight regain, without constantly increasing effort, which it isn't realistic to expect.

Gloomy! IMO this is the biggest challenge for eg the "Newcastle Diet" longer term. There's good evidence that losing enough weight can bring plenty of T2D's into normal BG territory, but how to maintain?


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## Eddy Edson (Sep 15, 2019)

Hall's original work on the carbohydrate-insulin hypothesis was funded by Gary Taubes' Nutrition Science Institute (NuSI). 

(Taubes of course being the journalist who has been a major proponent of the hypothesis and an important low-carb player.)

 NuSI got funding from philanthropic donors partly on the basis that it would engage top-ranked researchers like Hall who were not adherents of Taubesian views and give them scientific freedom to do the research.

When Hall's initial study found zero evidence for the hypothesis and in fact delivered a pretty strong falsification of the main idea, NuSI and Taubes started to interfere, reneging on its commitment. Taubes' fund raiser partner quit, Hall and others quit and NuSI lost its main donor, more-or-less killing it off.

IMO, it's a story which buttresses the notion that Taubes is pretty much a quack.

Taubes and Hall squabble from time to time on Twitter: https://twitter.com/KevinH_PhD/status/1172539797144928256

Some more background: https://www.stephanguyenet.com/nutrition-science-initiative-nusi-in-retrospect/


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## mikeyB (Sep 17, 2019)

I’ve been following this argument with yourself avidly. Just thought you’d like to know you’ve answered all the queries I had. Carry on like this and I’ll be out of business


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## Eddy Edson (Sep 17, 2019)

mikeyB said:


> I’ve been following this argument with yourself avidly. Just thought you’d like to know you’ve answered all the queries I had. Carry on like this and I’ll be out of business


Cool! Who's winning?


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## Docb (Sep 17, 2019)

Tried to get my old and cold laden brain around those papers but largely failed.  One thing that occurred to me with respect to the first study was that the subjects ate as much or as little as they wanted from the various diets.  The diets were balanced for just about everything but I could not see whether they were balanced for energy density.  Was the volume of food presented for a given calorie intake the same in both diets?


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## Bruce Stephens (Sep 17, 2019)

Docb said:


> The diets were balanced for just about everything but I could not see whether they were balanced for energy density.



According to the presentation I listened to, no. That was one of the factors they thought might well be significant (and presumably they couldn't think of a way to control for).


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## Docb (Sep 17, 2019)

Easy, you treat the subjects like mice and force-feed them controlled portions. Mmm, maybe not as easy as mice. Perhaps you could photograph meals and do some estimation.  My thought was that if you let people decide their own portion size and if they tended to go for the same volume, they would take more calories in with one diet or the other if the calorie density was different.


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## Eddy Edson (Sep 17, 2019)

Docb said:


> Easy, you treat the subjects like mice and force-feed them controlled portions. Mmm, maybe not as easy as mice. Perhaps you could photograph meals and do some estimation.  My thought was that if you let people decide their own portion size and if they tended to go for the same volume, they would take more calories in with one diet or the other if the calorie density was different.



I suppose the fact that there was no sig diff in subjective satiation between the diets gives some sort of control. 

But they do discuss the energy density diff as being a possible explanation.


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## Bruce Stephens (Sep 17, 2019)

Docb said:


> Easy, you treat the subjects like mice and force-feed them controlled portions.



But then you'd be missing what they were looking at, wouldn't you? The whole idea was to look at what people would want to eat, and whether that could be explained by salt, sugar, fat, etc., so force feeding people surely wouldn't be useful for that? (There are obvious experiments you could usefully do if you could lock people in cages and feed them controlled diets for long enough periods, but it doesn't look to me like this would be one of them.)


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## Eddy Edson (Sep 18, 2019)

Docb said:


> Tried to get my old and cold laden brain around those papers but largely failed.  One thing that occurred to me with respect to the first study was that the subjects ate as much or as little as they wanted from the various diets.  The diets were balanced for just about everything but I could not see whether they were balanced for energy density.  Was the volume of food presented for a given calorie intake the same in both diets?



From the paper:

_The foods and beverages consumed during the ultra-processed diet had greater energy density than the unprocessed diet (1.36 ± 0.05 kcal/g versus 1.09 ± 0.02 kcal/g; p = 0.0008). While the presented ultra-processed and unprocessed meals had similar energy densities (Table 1), this was due to inclusion of beverages as vehicles for the dissolved fiber supplements in the ultra-processed meals that were otherwise low in fiber. However, because beverages have limited ability to affect satiety (DellaValle et al., 2005), the ∼85% higher energy density of the non-beverage foods in the ultra-processed versus unprocessed diets (Table 1) likely contributed to the observed excess energy intake (Rolls, 2009).

...

Previous studies have demonstrated that higher eating rates can result in increased overall energy intake (de Graaf and Kok, 2010, Forde et al., 2013, McCrickerd et al., 2017, Robinson et al., 2014) such that a 20% change in eating rate can impact energy intake by between 10% and 13% (Forde, 2018). Perhaps the oro-sensory properties of the ultra-processed foods (e.g., softer food that was easier to chew and swallow) led to the observed increased eating rate and delayed satiety signaling, thereby resulting in greater overall intake (de Graaf and Kok, 2010). Future studies should examine whether the observed energy intake differences persist when ultra-processed and unprocessed diets are more closely matched for dietary protein and non-beverage energy density while at the same time including ultra-processed foods that are typically eaten slowly._


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## Docb (Sep 18, 2019)

Fair enough, Eddy, they are thinking about it.  

I was wondering about calories per unit volume rather than weight and the implications of subjects selecting portion sizes based on the size of a dollop rather than its weight.


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