In 2016 I wrote a post entitled “Ultra-Processed Foods Contribute Half Of The Calories And 90% Of The Added Sugar to US Diets.’
And in 2020 I wrote about two studies implicating ultra-processed foods in the obesity epidemic.
In the last year the topic of high UPF diets causing all manner of chronic diseases has become hot and a book entitled “Ultra-processed People: Why we can’t stop eating food that isn’t food” written by Chris Van Tulleken, an English infectious disease doctor was recently named the Sunday Times science book of the year.
I can’t say the science behind UPF has changed much since 2020. We still have lots of unanswered questions. Identifying what specific characteristics of UPF makes them bad and even the definition of what a UPF is has become controversial.
Observational studies from a Brazilian scientist kicked off the focus on added UPFs which I described in 2020.
BRAZIL LEADS IN RECOGNIZING THE DANGERS OF ULTRA-PROCESSED FOODS
The Guardian published a long article in 2020 which does a great job of providing an easily digested background to the concept of UPFs and their influence on obesity. A lot of that background comes from the work of a Brazilian MD, Carlos Monteiro:
The concept of UPFs was born in the early years of this millennium when a Brazilian scientist called Carlos Monteiro noticed a paradox. People appeared to be buying less sugar, yet obesity and type 2 diabetes were going up. A team of Brazilian nutrition researchers led by Monteiro, based at the university of Sao Paulo, had been tracking the nation’s diet since the 80s, asking households to record the foods they bought. One of the biggest trends to jump out of the data was that, while the amount of sugar and oil people were buying was going down, their sugar consumption was vastly increasing, because of all of the ready-to-eat sugary products that were now available, from packaged cakes to chocolate breakfast cereal, that were easy to eat in large quantities without thinking about it.
I highly recommend you read the full article in the Guardian on this important topic. It is extremely well-written and the author has interviewed both Monteiro and Kevin Hall for the piece.
Added Sugar versus Processed Food
Many of my early skeptical cardiologist posts ranted about the deleterious effects of added sugars from highly processed food in our diets (see here or here)
I pointed out evidence showing the major role that the sugar industry played in vilifying fat and obscuring the dangers of excess sugar in the diet.
For example, evidence that Big Sugar paid three Harvard scientists in the 1960s to play down the connection between sugar and heart disease and instead point the finger at saturated fat. Coca-Cola and candy makers made similar headlines for their forays into nutrition science, funding studies that discounted the link between sugar and obesity.
An observational study published from Monteiro, et al. in BMJ Open confirmed the presumed close association between highly processed foods and added sugar
Carlos Monteiro and his colleagues begin this paper by noting that dietary guidelines are increasingly recommending limiting added sugar to <10% of dietary calories because of evidence that:
“a high intake of added sugars increases the risk of weight gain, excess body weight and obesity ;type 2 diabetes mellitus, higher serum triglycerides and high blood cholesterol; higher blood pressure and hypertension; stroke; coronary heart disease; cancer; and dental caries. Moreover, foods higher in added sugars are often a source of empty calories with minimum essential nutrients or dietary fibre which displace more nutrient-dense foods and lead, in turn, to simultaneously overfed and undernourished individuals.”
The study analyzed the relationship between processed food consumption, total calories and calories from added sugar using data from the National Health and Nutrition Examination Survey 2009–2010.
They divided foods into four categories:
–unprocessed or minimally processed foods (such as fresh, dry or frozen fruits or vegetables, grains, legumes, meat, fish and milk)
–processed culinary ingredients’ (including table sugar, oils, fats, salt, and other substances extracted from foods or from nature, and used in kitchens to make culinary preparations)
–processed foods’ (foods manufactured with the addition of salt or sugar or other substances of culinary use to unprocessed or minimally processed foods, such as canned food and simple breads and cheese)
–ultra-processed foods (formulations of several ingredients which, besides salt, sugar, oils and fats, include food substances not used in culinary preparations, in particular, flavours, colours, sweeteners, emulsifiers and other additives used to imitate sensorial qualities of unprocessed or minimally processed foods and their culinary preparations or to disguise undesirable qualities of the final product.
The most common ultra-processed foods in terms of energy contribution were breads; soft drinks, fruit drinks and milk-based drinks; cakes, cookies and pies; salty snacks; frozen and shelf-stable plates; pizza and breakfast cereals.
The findings:
ultra-processed foods account for 58% of all calories in the US diet, and contribute nearly 90% of all added sugars.
What wasn’t clear from the observational studies was whether added sugar was the major culprit or the fact that the food was ultra-processed or some other factor. (That is always the problem with observational studies.)
Kevin Hall’s Stunning Study
In 2020 I listened to an episode of the (now defunct) podcast Best Known method which featured the NIH nutrition researcher Kevin Hall discussing ultra-processed foods with Ethan Weiss.
The early part of the podcast reviews Hall early training in physics and mathematics and transition into mathematical modeling of metabolism. Ultimately he ended up testing the hypothesis that a diet of UPF with similar macronutrient composition would result in greater weight gan than an unprocessed diet
The results were published in Cell Metabolism and are summarized in this neat graphic.
Yes. you read that correctly.
In 20 inpatient adults (10 men and 10 women) the ultra-processed diet caused increased ad libitum energy intake and weight gain despite being matched to the unprocessed diet for presented calories, sugar, fat, sodium, fiber, and macronutrients
Hall had expected negative results from this study but now believes something about UPFs beyond their macronutrient composition causes many individuals to overeat and gain weight.
Whereas in 2016 I thought the major culprit was the added sugar in UPFs, Hall’s study suggests it is not just added sugar or missing fiber in the diet that is leading to excess eating and weight gain.
I consider Kevin Hall the leader in this field and I strongly recommend following him on X. He is free of bias and is appropriately conservative in all his statements on UPFs.
As he indicates, the focus should be on unraveling mechanisms.
IDENTIFYING ULTRA-PROCESSED FOODS
I provided some light-hearted guidance on identifying UPFs in my unpublished 2016 post:
If you have difficulty in determining what foods should be considered ultra-processed I recommend getting a copy of Michael Pollan’s small and delightful booklet, “Food Rules: An Eater’s Manual.”
The first section entitled “Eat Food” provides 21 short, memorable phrases to help you identify and avoid ultra-processed foods: concoctions that he terms “edible food-like substances.”
Some of the key rules:
Don’t eat anything your grandmother wouldn’t recognize as food.
Avoid food products that contain ingredients that no ordinary human would keep in the pantry
Avoid food products that contain high fructose corn syrup
Avoid foods that have some form of sugar (or sweetener) listed among the top three ingredients
Avoid food products that contain more than five ingredients
And one that I particularly like as it emphasizes the misleading health claims of low fat diary:
Avoid food products with the wordoid “lite” or the terms “low-fat” or “nonfat” in their names.
I still think this is good advice but I’ll delve deeper into the controversies surrounding the UPF definition in a future post.
Ultraunprocessedly Yours
-ACP
I always find it striking how slim the actors look in 1970s - early 1980s television series. They don’t even look as though they achieved slimness through hard work at a gym. Many were eating so-called ‘balanced diets’ which included white bread and potatoes. There were ‘balanced’ meals available for lunch in many a canteen too, and at school. Children mostly ate these meals, cooked on the premises, rather than packed lunches. I don’t have much faith in the idea of re-formulating UPF as I don’t think that it will be improved unless we all expect better quality, and the trouble is that we don’t.
I would agree