Today I'm going to take a look at ultra-processed foods and their effect on energy balance, meaning risk for obesity.
It’s an important question when you consider that nearly 3 in 4 Americans are either overweight (31%) or obese (42%) and roughly 60% of calories are coming from ultra-processed foods. We Europeans are not that far from that.
I won’t be getting into their effects on the microbiome or risk of other diseases, just energy balance. But I think you’ll find this one highly compelling….
As you can see, the mainstream media covered this story pretty heavily when it came out in 2019, with some notably "clickbait-y" headlines:
But we’re going to dive deeper and emerge with a better understanding of this study.
Today we are reviewing...
"Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake" ✍️Hall KD, Ayuketah A, Brychta R, et al. Cell Metabolism. 2019
How do we define "ultra-processed?
The NOVA classification system was developed to help us separate foods into 4 main types:
Group 1 - unprocessed foods
Group 2 - processed culinary ingredients
Group 3 - processed foods
Group 4 - ultra-processed foods
As I always mention, my fight isn’t with processed foods. We ALL process foods… Even chewing your food is processing it. So let’s not get crazy here.
Are you most of the time consuming food from group 1?
Yes
No
But ultra-processed foods are another story.
Ultra-processed foods are industrial formulations that contain little or no whole foods and generally an unnatural amount of salt, oil, and sugar. Further, to keep foods intact, give them a desired texture, make them a nice bright colour, and prevent spoilage for years on end ultra-processed foods also contain food additives such as hydrogenated or interesterified oils, hydrolyzed proteins, concentrated food constituents (like casein, whey and gluten), variant forms of sweeteners (there are over 50 names used for sugar), preservatives, dyes, colour stabilizers, artificial flavours, artificial flavour enhancers, bulking and anti-bulking agents, anti-caking and glazing agents, emulsifiers, humectants, sequestrants.
There’s more, but I’m tired…
The bottom line is that if I give you an unlimited budget, unlimited culinary talent, and unlimited kitchen equipment you still wouldn’t be able to create ultra-processed foods using whole foods. Not possible unless you’re a food scientist and you seek out industrial food tools far beyond an Instant Pot.
This emphasizes the need for systemic changes in food production and distribution to make healthier, less processed foods more accessible and affordable.
Finally, one of the unanswered questions from this study is what specific components or properties of ultra-processed foods lead to the observed increase in calorie intake and weight gain. Here are a few of the possibilities that I’m thinking about: 1. Eating rate. We know that a slower rate of eating allows gut satiety hormones like GLP-1 and Peptide YY to be released. The eating rate could be measured in weight (grams per minute) or energy (kilocalories per minute). It doesn’t really matter how you measure it because either way you know they were eating faster on the ultra-processed diet.
2. Energy density. Food energy density is defined as the energy content (in kcal or kJ) per unit of weight (g or 100 g). Research indicates that in people who are obese, if they gravitate towards foods with low energy density they are likely to lose weight.
3. Poor satiation. Interestingly, the appetite-suppressing hormone PYY increased during the unprocessed diet and the hunger hormone ghrelin was decreased during the unprocessed diet compared to baseline. This suggests the unprocessed diet was more satiating.
4. The food matrix. In the past, we have focused on isolated nutrients, as if the context in which you find those nutrients makes no difference. But there’s a problem with this… When you take that nutrient away from its native state, it may behave completely differently. Research has shown that disruption of the food matrix can alter our metabolic responses and energy intake. In other words, don’t reduce the science to individual nutrients, look at the whole food which includes the food matrix and broader context.
5. Gut microbiome. Last but not least, how can we deny the possibility that the additives in ultra-processed foods might disrupt our gut microbiome? It’s impossible to comment on the 10,000 food additives already in our food supply because they were grandfathered in before microbiome testing and no one seems interested in the labour intensity necessary to reconsider the impact they have on the gut microbiome.
What you should do about it
First, focus on unprocessed foods whenever possible. Look, I get it… Life is busy, ultra-processed foods are easy, quick and cheap. None of us are perfect. But our current pattern where 60% of calories come from ultra-processed foods is destroying our health. We may not get it to 0%, but if you drop the ultra-processed and replace it with whole plant foods you are MOST DEFINITELY moving in a direction that is better for you and your microbes. Second, let’s circle back to the eating rate for a moment. You can eat the exact same food, but if you slow it down you will increase your satiety and make yourself less likely to overeat. So the point is we should be careful about aggressive or fast eating, taking meals on the go, or sneaking in a whole meal before you run out the door. Sometimes it’s necessary, but most of the time we need to slow our roll, sit down at a table, preferably with another human, and have some conversation between taking bites of our food. Perhaps this explains why the French are so thin, yet eat so much cheese! You’re not getting out of that French cafe in under 90 minutes.
And that's all, folks! Have a great week ahead,
Warm regards,
Adriano dos Santos, BSc, rNutr, AFMCP, MBOG, RSM, ESIM
Functional Nutritionist
MSc Student Sleep Medicine
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