Cellophane-wrapped bread, strawberry-flavored yogurt, whole-grain breakfast cereals, steak paste, protein snack bars, gummy bears, hot dog sausages, supermarket cupcakes, and microwave lasagna represent just a small sample of ultra-processed foods (UPF) available today.
Ultra-processed foods are industrially made using ingredients and techniques not typically found in home kitchens, accounting for over half of the average person’s diet in England and the U.S.
This statistic is concerning; a higher intake of UPF is linked to a wide array of health issues, including obesity, type 2 diabetes, heart disease, and various cancers.
While reading the lengthy ingredient list of a prepared meal, you might attribute your concerns to the unfamiliar additives present.
That’s not entirely unfounded. Research shows that certain additives in UPF can contribute to adverse health effects.
For instance, specific food dyes have been linked to hyperactivity in children, and some preservatives in processed meats can increase cancer risk. Furthermore, particular emulsifiers may harm the gut microbiome.
While these issues are significant, scientists are increasingly highlighting a less obvious factor: texture.
“These additives and emulsifiers aren’t the only reasons ultra-processed foods are detrimental,” says Professor Sarah Berry, a nutritionist at King’s College London. “The texture of ultra-processed foods is typically modified to be softer, leading us to consume them more quickly and, in turn, more overall.”
It may seem simplistic, but the ease of consumption with softer foods substantially impacts our dietary habits.
The Impact of UPF Consumption
To understand how UPF affects daily calorie intake, refer to this groundbreaking UPF research led by American nutritionist Kevin Hall.
In this study, 20 participants consumed either a minimal or ultra-processed diet for two weeks, alternating diets every two weeks.
These meals were nutritionally balanced for calories, carbohydrates, protein, fat, sugar, salt, and fiber, allowing participants to eat freely.
Those consuming ultra-processed foods averaged an additional 500 calories per day, primarily from fats and carbohydrates, and gained nearly 1kg over the study’s duration.
What explains this phenomenon? An analysis of the Hall study confirmed that participants ate ultra-processed foods more rapidly.
Soften foods lead to quicker consumption. When manufacturers process food, they often compromise the natural structure, creating a texture that melts in your mouth and requires minimal chewing.
In the study, the ultra-processed diet was notably softer, encouraging participants to challenge themselves less while eating.
“We’ve demonstrated that faster eating rates correlate with increased energy expenditure,” says Professor Ciaran Forde of Wageningen University in the Netherlands.
Research indicates that a 20% increase in eating speed leads to more frequent snacking opportunities and increased calorie intake.
“Eating quickly generally increases your intake, irrespective of whether the food is pure, unrefined, or minimally processed. The quicker it’s consumed, the larger the quantity,” explains Forde.
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People who tend to eat swiftly are more likely to be overweight, have high blood pressure, and be at risk for type 2 diabetes.
“Digestion begins in the mouth, not the stomach,” Forde clarifies. “The way you chew influences how food is digested and how satiated you feel.”
As you eat, the muscles surrounding your stomach stretch gradually, signaling fullness, albeit with some delay.
“There’s a delay between the initial diet and the subsequent chemical changes in the brain,” Forde says. “Our studies show that chewing the same calories for longer fosters a stronger sense of satisfaction.”
This means that softer foods requiring little chewing (common in many UPFs) can lead to consuming a larger quantity before your body indicates fullness.
“Common traits among junk foods include being soft and energy-rich,” adds Forde. “This often leads to unintentional overeating.”
Diversity of UPF Textures
You might wonder if all UPFs are soft. Some, like protein bars or granola with nuts, are crunchy or chewy. Doesn’t that slow consumption?
This question prompted Forde to conduct another experiment, where his team created a trial that, like Hall’s, involved two diets over two weeks.
However, this time both meals were 95% ultra-processed, differing mainly in texture: one meal contained chewy, crunchy foods designed for slower consumption, while the other was characterized by softer, spongy options.
“What we discovered was surprising,” remarks Forde. “In the absence of instructions, participants ate 370 fewer calories on average when consuming harder foods.”
The 41 study participants substantially increased their intake on the softer diet, gaining around 500g of body fat.
“All the foods in our trial were ultra-processed,” Forde states. “So while you can argue that many ultra-processed items are soft and energy-dense, we identified a distinct subgroup of ultra-processed foods that can be eaten more slowly.”
These findings align with insights from a large-scale observational study, suggesting UPF categorization isn’t monolithic.
Interestingly, studies linking UPF to conditions such as type 2 diabetes often exclude whole grain bread, flavored yogurt, plant-based meat substitutes, and breakfast cereals as major offenders.
Combined with Forde’s research on texture, this reveals that not all ultra-processed foods are equally detrimental.
“Sometimes our results are misinterpreted to suggest that all UPFs are harmful and promote excessive calorie intake,” Forde explains. “This is a misapplication of our findings.”
“We can move past simple distinctions between good and bad processed foods,” he adds. “It’s crucial to be mindful of foods that are calorie-dense and consumed quickly (many, though not all, of which fall into the ultra-processed category) and to substitute them with more enjoyable fare that requires longer to eat.”
“This could be part of the solution moving forward,” Forde suggests. “By focusing on adding texture to your meals, you can make adjustments within your preferred food spectrum. Numerous processed options can contribute to this.”
“Embrace the joy of eating while feeling satisfied without guilt.”
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Source: www.sciencefocus.com