Ultra-processed foods and calories: more evidence!
A diet of ultra-processed foods that are 'energy dense' and 'hyper-palatable' leads healthy adults to consume an extra 1000 kcal/day, compared with a nutritionally matched diet of minimally processed food, according to preliminary results from a new controlled trial
FAB RESEARCH COMMENT:
Preliminary findings from a new randomised controlled trial show that diets made up of ultra-processed foods (UPF) lead to significant overeating, compared with a nutritionally matched diet of minimally processed (real) foods.Importantly, the degree of that excess food intake varied according to both the 'energy density' (calories per gram) and the 'hyper-palatability' of the UPF included - and ranged from around 250 to a massive 1000 kcal/day for UPF high on both these dimensions.
They are also entirely consistent with those of previously published trials showing greater calorie intake from UPFs in comparison to less processed foods.
These results are very important - because a ever-increasing body of research linking overeating and obesity to the consumption of UPF has to date been downplayed as 'insufficient to show causality" without additional evidence from human RCTs - not only by the food industry (who have a rather obvious vested interest) but by many academics, professionals and policymakers.
As a result, official Dietary guidelines and Public health advice have continued to ignore or downplay the 'UPF issue', while rates of overweight, obesity and related health problems have continued to rise - especially in children and young adults, whose diets tend to be highest in UPF.
These top-line results from this new trial were revealed by the lead researcher Dr Kevin Hall in a conference presentation in London last month. His talk begins at minute 38 of this openly available Youtube video:
- Ultra-processed food: the scope for Government action - a Youtube recording of the conference jointly organised by the Centre for Health Economics & Policy Innovation at Imperial College `Business School, the NIHR School of Public Health Research and the Imperial Policy Forum.
For more information on Hall's previous groundbreaking clinical trial in 2019 - which these new data would clearly appear to support and extend - please see the associated news articles:
For details of the research (which is open-access - and includes an Appendix with in-depth information on how carefully the diets were nutritionally matched - including examples of the actual meals) see:
This 2019 study involved healthy young adults living in the US - for whom the UPF vs non-UPF diet led them to consume an extra 500 calories/day, and gain almost a kilogram of weight in 2 weeks (as well as worsening various meaures of metabolic health).
A more recent randomised controlled trial (RCT) from Japan - involving adults with obesity - reported that they consumed an additional 800 calories / day on a UPF vs minimally processed diet.
They also found that chewing of food per calorie was significantly lower for the UPF than in the 'real food' diet. This is consistent with the idea that one reason why UPF promote overeating is the sheer speed with which they can be consumed - allowing less time for satiety signals from the gut to reach the brain.
For details of this research see:
And for more information on the mental health links with UPF consumption please see:
And for more information on this important topic, please see the following article lists, which are frequently updated:
3rd December 2024 - Food Politics
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Two previous short-term studies demonstrated that if you eat a diet based largely on ultra-processed foods, you are likely to consume far more calories than you would eating less processed diets–and not notice that you are overeating.
The big question: why.
Study #1: Hall K, et al. Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake . Cell Metabolism 2019; 30:67–77.
When study subjects ate the ultra-processed diet, they consumed 500 calories a day more than when they were eating the unprocessed diet. This is a staggering difference. They seemed to eat the ultra-processed diet faster.
Study #2: Hamano S, Sawada M, Aihara M, Sakurai Y, Sekine R, Usami S, Kubota N, Yamauchi T. Ultra-processed foods cause weight gain and increased energy intake associated with reduced chewing frequency: A randomized, open-label, crossover study. Diabetes Obes Metab. 2024 Nov;26(11):5431-5443. doi: 10.1111/dom.15922.
These investigators reported a difference of 813 calories. They attributed it to less chewing.
Study #3 (as yet unpublished): Its results appeared as a Tweet (X) from Dr. Hall describing a presentation he gave at a meeting in London (Apparently, X is where science gets discussed these days). The recording of the entire meeting is now available. Dr Hall’s presentation begins at minute 38.
The latest result: a difference of 1000 calories a day!
Dr. Hall was kind enough to send me the slides from his presentation.
My translation:
- Blue bar: Minimally processed diet, low in energy density (calories per gram) and low in irresistably delicious (hyper-palatable) foods.
- Red bar: Ultra-processed diet high in energy density and high in hyper-palatable foods.
The big result: Difference between blue (unprocessed) and red (ultra-processed): 1000 calories a day.
- Purple bar: Ultra-processed high in energy density, low in hyper-palatable.
- Green bar: Ultra-processed low in energy density, low in hyper-palatable.
Difference between purple (high, low) and red: 200 calories a day.
Difference between green (low, low) and red: 630 calories a day.
Participants reported no differences in appetite or pleasantness of the meals on the various diets. There also were no observable differences in eating rate.
Obviously, participants who ate more calories gained more weight.
Comment
My summary: We love and cannot stop eating yummy high-calorie foods.
All of this reminds me of the work of Barbara Rolls, who for years has argued for diets low in energy density, and whose low-energy-dense Volumetrics diet is consistently ranked at the top of diet plans.
It’s great to see all this research coming together. Whatever the reasons—energy density, hyper-palatability, less chewing—the take-home-message seems utterly obvious: reduce intake of ultra-processed foods.
As Jerry Mande summarized the significance of this study, also in a Tweet (X) :
BREAKING..@KevinH_PhD presents preliminary data from long awaited (6yrs!) follow-up study. Confirm initial findings. Energy dense, hyper-palatable UPF foods result in 1000 kcal/day greater intake than minimally processed food. Time to regulate UPF #MAHA
Indeed, yes.
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