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…the list of ultra-processed foods (UPF) is virtually endless.

These foods are industrially produced using ingredients and methods not typically found in home kitchens, with more than half of the average person’s diet in England and the US consisting of UPF.

The implications of this are concerning. The more ultra-processed food you consume, the greater the risk of developing health issues like obesity, type 2 diabetes, heart disease, and various cancers.

If you’re scanning a long list of unfamiliar additives while enjoying a prepared meal, you may be right to worry.

Research suggests that certain chemicals in UPF are linked to negative health outcomes. For instance, some food dyes have been associated with hyperactivity in children, and preservatives in processed meats have been linked to an increased risk of cancer. Specific emulsifiers can also harm gut microbiomes.

While these factors are indeed problematic, they’re not the entire issue. Scientists have increasingly focused on another, less obvious contributor: texture.

“These additives and emulsifiers aren’t the sole reason ultra-processed foods are detrimental,” states Professor Sarah Berry, a nutritionist at King’s College London. “Ultra-processed foods typically have altered textures, making them much softer, which enables faster consumption and greater overall intake.”

It may seem trivial, but ease of consumption is shifting how scientists understand the health consequences of UPF.

Overconsumption of UPF

To understand how UPF impacts daily calorie intake, groundbreaking research led by American nutritionist Kevin Hall sheds light on the issue.

In the study, 20 participants alternated between a minimal diet and an ultra-processed diet over two weeks each, with meals calibrated for calories, carbohydrates, protein, fat, sugar, salt, and fiber, allowing for unrestricted consumption.

Participants consuming ultra-processed foods consumed an average of 500 extra calories daily—primarily from fats and carbohydrates—and gained nearly 1 kg in weight.

But why is this the case? Analysis revealed that participants consumed ultra-processed foods at a quicker pace.

The softer the food, the faster it’s typically eaten. Furthermore, manufacturers often alter the natural structure of ingredients to create a soft, melt-in-your-mouth texture that requires minimal chewing.

The UPF diet in Hall’s study was notably softer than that of its minimally processed counterpart, enabling quicker consumption.

“Our research has consistently demonstrated that faster eating rates correlate with higher energy expenditure,” claims Professor Ciaran Forde from Wageningen University in the Netherlands.

Research indicates that eating 20% faster can significantly increase calorie intake per sitting, with effects documented in several studies.

“Faster eating, regardless of food type, leads to greater intake,” adds Forde. “No matter how healthy the food, quicker consumption results in larger quantities consumed.”

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Individuals who eat quickly are significantly more likely to experience issues like overweight, hypertension, and type 2 diabetes risks.

“The initial stage of digestion occurs in the mouth, not the stomach,” explains Forde. “The way you chew influences digestion and how full you feel afterward, priming your body to absorb nutrients.”

As you eat, stretch receptors in your stomach signal fullness, although this process is not instantaneous.

“A time lag exists between eating and the resulting hormonal changes in the brain,” Forde notes. “We found that chewing the same calorie count for a longer period results in a stronger sense of satisfaction.”

Thus, when consuming soft foods that require little chewing, particularly in many UPFs, you can consume large quantities before feeling full.

“Soft texture and energy density are common traits in junk foods,” says Forde. “Consequently, you’re likely to ingest excess calories without realizing it.”

Not All UPFs Are Created Equal

You might wonder if all UPFs are soft. Some, like protein bars or granola with nuts, are crunchy or chewy. Do these textures not slow consumption?

This led Forde to conduct another experiment. His team designed a study similar to Hall’s, featuring two diets that prioritized nutrition and flavor, each for two weeks.

This time, both diets were 95% ultra-processed, with the main difference being texture: one meal consisted of chewy, crunchy, and harder foods designed for slower eating, while the other was soft, spongy, and moist.

“The results were astonishing,” states Forde. “Without any specific instructions, participants averaged a consumption reduction of about 370 calories.” They also gained nearly 500g of body fat on the faster diet.

“All foods in our trials were ultra-processed. However, while many UPFs are energy-dense and soft, we identified some that can be consumed more slowly,” adds Forde.

This aligns with insights from a large-scale observational study, revealing that not all UPF categories carry equal health risks.

Interestingly, studies noting a correlation between UPF and conditions like type 2 diabetes highlighted exceptions including whole grain bread, flavored yogurt, plant-based meat alternatives, and breakfast cereals.

Considering Forde’s texture findings, a variety of healthy elements exist within the ultra-processed category.

“Our findings are sometimes misinterpreted as proof that all UPFs promote excessive calorie consumption,” Forde notes. “Such simplifications do not reflect our complex results.”

Forde stresses the importance of discerning “red flags” associated with calorie-rich, easily consumed foods (many, though not all, of which are ultra-processed) and swapping them for equally satisfying options that require more time to eat.

“This could be part of future solutions,” Forde asserts. “By adding texture to your meals, you can make mindful choices within the foods you already enjoy.

“It’s possible to find joy in eating and feel satiated without guilt.”

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