Why are ultra-processed foods so easy to overeat? For years, the simplest answer was that they are highly palatable, convenient and often energy-dense. But newer research is beginning to reveal a more useful picture.

It may not be processing alone that matters. Food texture, eating speed, energy density and the rate at which energy arrives may all influence how much we eat before the body has time to register that enough food has been consumed.

This matters because modern snack foods are often designed to be soft, easy to chew, quick to swallow and extremely convenient. That combination can make it possible to consume a large amount of energy in a surprisingly short period of time.

Recent controlled trials are now testing those mechanisms directly.

The results do not support the idea that every ultra-processed food behaves identically. Instead, they suggest that how a food is structured, how quickly it is eaten and what nutrients it delivers may be central to understanding why some foods are so easy to overconsume.

What Do We Mean by Ultra-Processed Food?

Ultra-processed foods are commonly discussed using the NOVA classification system. In simple terms, these are industrially formulated foods that often contain ingredients or additives not normally used in a home kitchen.

Examples can include:

• biscuits and confectionery
• many breakfast cereals
• crisps and flavoured snack foods
• soft drinks
• some ready meals
• many protein bars
• sweetened yoghurts and desserts
• certain packaged breads and bakery products

But the category is broad.

That is important because two foods can both be classified as ultra-processed while having very different nutritional profiles, textures, protein contents and effects on eating behaviour.

So the most useful question may not be simply:

“Is this food ultra-processed?”

It may also be:

“What properties of this food make it easy or difficult to overeat?”

The Landmark Experiment: People Ate More on an Ultra-Processed Diet

One of the most important experiments in this area was published by researchers at the US National Institutes of Health in 2019.

Twenty adults stayed at the NIH Clinical Center and were given either an ultra-processed diet or an unprocessed diet for two weeks before switching to the other diet.

The meals were designed to be broadly matched for several nutritional variables, and participants were allowed to eat as much or as little as they wanted.

The result attracted enormous attention.

Participants consumed roughly 500 more calories per day while eating the ultra-processed diet and gained weight during that phase.

When they ate the unprocessed diet, they consumed less energy and lost weight.

The study was small, but because it was a tightly controlled feeding trial it provided much stronger evidence than an observational association alone.

What it did not fully answer was why.

That question has become the focus of newer research.

New Research: Eating Speed May Be Part of the Explanation

A major clue is eating rate.

In a 2026 randomised crossover trial, researchers compared two ultra-processed diets designed to differ in how quickly their foods could be eaten.

The diets were matched for factors including palatability, portion size, meal variety and non-beverage energy density. The major difference was the texture of the foods and the resulting eating speed.

The finding was striking.

Participants consumed about 369 fewer calories per day on the slower-eating ultra-processed diet than on the faster-eating version.

Both diets were ultra-processed.

Yet changing the physical properties of the foods changed how much people voluntarily ate.

This suggests that the label “ultra-processed” may not fully explain the effect by itself.

How quickly the food can be chewed, swallowed and consumed may be a major part of the mechanism.

Why Eating Quickly Can Matter

Eating is not just a matter of putting energy into the body.

It is also a sensory and physiological process.

Chewing, swallowing, stomach filling, gut signalling and hormonal responses all contribute to satiation — the process that helps bring a meal to an end.

If a food allows you to consume a large amount of energy very quickly, there may simply be less time for those signals to influence how much you eat before the meal is over.

A soft, energy-dense snack can sometimes disappear in a few bites.

A tougher piece of meat requires chewing. It stays in the mouth longer. Eating it involves more physical work and usually takes more time.

From a carnivore perspective, that contrast matters. Meat is protein-rich, physically substantial and generally slower to eat than the soft, refined foods that dominate the modern snack aisle.

Protein and Fat Can Both Help a Meal Feel Satisfying

Protein gets most of the attention in discussions about satiety, and for good reason. It is consistently one of the most filling macronutrients and is essential for maintaining and repairing tissue.

But fat also contributes to satisfaction. It adds richness, slows gastric emptying and provides a dense source of energy. In the context of a protein-rich meal, animal fat can make food feel more substantial and help that meal last longer.

That is very different from saying “more fat is always better”. Context matters. Fat consumed alongside substantial protein in a simple food such as beef is not the same eating experience as fat combined with refined starch, sugar and flavourings in a biscuit or pastry.

For us, the useful combination is protein plus naturally occurring animal fat — not refined carbohydrate plus added fat.

Energy Density Matters Too

Eating rate becomes even more important when combined with energy density.

Energy density simply means how much energy is contained in a given weight of food.

A food that is both:

• easy to eat quickly, and
• high in energy per gram

can deliver a very large amount of energy before much time has passed.

Researchers sometimes describe this as the energy intake rate: how much energy is being consumed per minute.

This is a useful way of thinking about modern snack foods.

The problem is rarely one ingredient in isolation. It is usually the combination:

• high energy density
• rapid eating
• soft texture
• easy swallowing
• high palatability
• refined carbohydrate
• added fat
• large portion availability

Put those features together and you have a food that is remarkably easy to keep eating long after a simple meal of meat or eggs would have felt sufficient.

The Refined Carb and Fat Combination Is a Major Problem

One of the most important features of modern processed food is the deliberate combination of refined carbohydrate and added fat.

Biscuits, doughnuts, pastries, chocolate, ice cream, crisps and many snack bars all use this basic formula. It is a very different nutritional package from most minimally processed foods.

Food manufacturers do not leave palatability to chance. Products are formulated and tested around combinations of fat, sugar or starch, salt, flavour and texture that make them highly rewarding and easy to continue eating.

That does not mean every person who eats these foods is “addicted” in a medical sense. But it is entirely reasonable to recognise that many of these products are designed to encourage repeat eating and can feel far harder to stop eating than simple whole foods.

Research on food reward also suggests that foods combining fat and carbohydrate can be especially attractive compared with foods dominated by either nutrient alone.

From a carnivore perspective, this is exactly why we prefer simpler animal foods. A steak, eggs, jerky or pemmican does not depend on a carefully tuned mix of refined starch, sugar and flavour engineering to make it appealing.

Metabolic State Matters Too

Food is not simply dropped into the body and automatically stored.

The body is constantly deciding how incoming energy is handled — whether it is used immediately, stored for later, released from storage or directed toward repair and other physiological processes.

Those decisions are influenced by hormones, nutrient availability, activity, recent meals and overall metabolic state.

Insulin is one important part of that system, particularly after carbohydrate-containing meals, but it is not the only hormone involved. Glucagon, gut hormones, stress hormones and signals from stored energy all contribute to how the body manages fuel.

Energy balance still matters, but the route to that balance is biological, not just mathematical. Appetite, satiety, fuel availability and hormonal signalling all influence how much we want to eat and how the body handles what we eat.

That is one reason we prefer foods that make appetite easier to manage rather than foods that require constant restraint.

What About Sugar, Blood Glucose and Hunger?

Refined carbohydrate can be consumed quickly and can produce a rapid rise and fall in blood glucose, particularly when eaten in a low-protein, highly processed form.

For some people, that post-meal drop is associated with greater hunger and an earlier desire to eat again.

We would not describe every rise in blood glucose as harmful, nor claim that healthy people are incapable of handling carbohydrate. The body has systems for doing exactly that.

But from an appetite perspective, a food that is rapidly digested, easy to overeat and leaves you wanting to eat again soon afterwards is not doing you many favours.

This is one of the practical reasons carnivore and very low-carbohydrate eaters often prefer meals built around protein and animal fat: the goal is to eat substantial food, feel satisfied and move on with the day.

Why Jerky Can Be So Satisfying

Jerky is a useful contrast to the modern soft snack.

Drying removes water and concentrates the beef into a compact food that is rich in protein. It also creates a dense, chewy texture that naturally slows eating.

A well-made jerky with a short ingredient list is minimally processed compared with most conventional snack foods. The processing is primarily preservation: slicing, seasoning and drying meat.

That matters because jerky gives you:

• concentrated protein
• high nutrient density
• a chewy texture that slows eating
• simple, recognisable ingredients when properly made
• a portable alternative to sweet or starch-based snacks

Protein, chewing and nutrient density can make a relatively small amount of jerky feel more substantial than a much larger volume of conventional snack food. That can make it easier to eat less overall without feeling as though you are deliberately restricting yourself.

Our own options include Ribeye Beef Steak Jerky and Chuck Beef Steak Jerky.

Why Pemmican Can Feel Even More Substantial

Pemmican takes the same basic idea further by combining dried meat with rendered animal fat.

That gives you both protein and fat in a compact, minimally processed form.

The dried meat provides protein and micronutrients. The animal fat provides concentrated energy and richness. Together, they make pemmican extremely dense, portable and satisfying.

Historically, that is exactly why pemmican made sense as travel food: a small amount could provide substantial nourishment without relying on sugar, flour or modern snack ingredients.

From a carnivore perspective, pemmican is close to the opposite of an ultra-processed snack. Instead of engineering refined carbohydrate and added fat into something easy to overeat, it combines animal protein and fat into something compact, rich and naturally self-limiting for many people.

Because it is so nutrient- and energy-dense, you do not need much of it to feel that you have actually eaten something.

You can try our Mixed Box of Pemmican Bars, or read more in our guide to What Is Pemmican?

Where Does Protein Fit Into the Picture?

Protein deserves special attention because it is generally regarded as the most satiating macronutrient.

Higher-protein foods can help support fullness and are also essential for maintaining and building lean tissue.

Interestingly, research on high-protein, lower-carbohydrate ultra-processed diets has found that people can consume less energy even when the foods still meet the definition of ultra-processed.

In one controlled study, a higher-protein, lower-carbohydrate ultra-processed diet led to lower voluntary energy intake than another ultra-processed diet.

The higher-protein diet was also eaten more slowly and required more chewing.

Again, that points towards an interaction between nutrient composition and physical food structure.

For us, that reinforces a simple principle: prioritise protein first, include enough natural animal fat to make the meal satisfying, and build meals around foods that do not leave you hunting for another snack an hour later.

We discuss protein and appetite in more detail in Protein: The Most Important Macronutrient for Fat Loss?

Why Modern Snacks Can Be So Easy to Overeat

It is easy to consume a packet of crisps, several biscuits, a sweet cereal bar, a chocolate bar or a soft dessert in a matter of minutes.

These foods often require relatively little chewing and can deliver substantial energy quickly.

By comparison, eating the same amount of energy from steak, eggs, jerky or pemmican can be a very different physical experience.

That is not an accident. Modern snack foods are built for convenience, palatability and repeat consumption. Whole animal foods are built by nature.

The emerging research helps explain why some foods make it easier to consume more energy without deliberately trying to do so.

Our related article The Real Problem With Most Modern Snacks: Why They Keep You Hungry explores this idea from a practical snacking perspective.

A Better Way to Judge a Snack

Instead of asking only whether a food is processed, ask:

• How much protein does it contain?
• Does it include enough natural fat to feel satisfying?
• How quickly can I eat it?
• Does it require meaningful chewing?
• How energy-dense is it?
• Does it combine refined carbohydrate with added fat?
• Does it contain added sugar?
• What does the ingredient list look like?
• Does it actually satisfy hunger?

Those questions can be more useful in real life than relying on a single front-of-pack label.

From a carnivore-friendly perspective, simpler usually wins: meat, eggs and other animal foods give you protein, fat and micronutrients without requiring a laboratory-style combination of sugar, starch, oils, flavourings and texture modifiers to make them desirable.

If you are looking for practical alternatives, see our guide to Best Keto, Carnivore and Low-Carb Snacks in the UK.

What the New Research Changes

The most interesting shift in the science is that researchers are moving from asking:

“Do ultra-processed foods make people eat more?”

to asking:

“Which characteristics of those foods make people eat more?”

That is a much more useful question.

The emerging answer appears to involve a combination of food structure, eating rate, energy density, nutritional composition and palatability.

For us, the practical takeaway is straightforward: prioritise substantial protein-rich foods, include natural animal fat where it suits you, and be sceptical of products built around refined carbohydrate, added fat and engineered palatability.

Frequently Asked Questions

Why do ultra-processed foods make you eat more?

Controlled research suggests that some ultra-processed diets can increase voluntary energy intake. Rapid eating, softer textures, high energy density and combinations of refined carbohydrate and added fat may all contribute. Processing classification alone does not explain every difference.

Is fat satiating?

Fat can contribute to satisfaction and fullness, particularly when eaten alongside substantial protein. It adds richness, slows digestion and provides dense energy. From our perspective, naturally occurring animal fat in meat is very different from added fat combined with refined starch and sugar in ultra-processed food.

Why can jerky be so filling?

Jerky is concentrated beef. It provides substantial protein, requires chewing and can be eaten relatively slowly. Those characteristics can make a small serving feel more substantial than a soft, rapidly eaten snack.

Why is pemmican so satisfying?

Pemmican combines dried meat with animal fat, giving you protein, fat and micronutrients in a compact food. It is highly nutrient- and energy-dense, so a relatively small amount can feel substantial.

Does metabolic state affect how food is used?

Yes. The body continually shifts between using, storing and releasing fuel. Hormones, activity, recent food intake, nutrient availability and overall metabolic state all influence those processes. Energy balance still matters, but it is regulated through biology rather than operating independently of it.

Why are fat and refined carbohydrate often combined in processed foods?

Because the combination can make foods highly palatable, energy-dense and easy to keep eating. Manufacturers can also optimise sweetness, saltiness, texture and flavour around that basic combination.

Is beef jerky ultra-processed?

Not necessarily. Jerky is processed because the meat is dried and seasoned, but a simple product made from beef, salt and straightforward seasonings is different from a heavily formulated product containing numerous industrial ingredients. Classification depends on the actual recipe.

Final Thoughts

Ultra-processed foods are often discussed as though they all behave in exactly the same way.

The latest research suggests the reality is more interesting.

Some ultra-processed diets clearly make it easier to consume more energy. Researchers are increasingly identifying the characteristics that may help explain why.

Eating speed matters.

Food texture matters.

Energy density matters.

Protein matters.

Natural fat can help a meal feel satisfying.

Metabolic and hormonal context influences how the body handles incoming fuel.

And the modern combination of refined carbohydrate, added fat and engineered palatability deserves particular scepticism.

Our preference is uncomplicated: start with meat, eggs and other recognisable animal foods, prioritise protein, include natural animal fat according to appetite, and choose foods that actually leave you satisfied.

Jerky and pemmican fit that philosophy extremely well: concentrated nutrition, simple ingredients, substantial protein, and food that feels like food rather than a formulation.

Research Referenced

• Hall KD 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.
• Forde CG et al. Eating rate has sustained effects on energy intake from ultraprocessed diets: a 2-week ad libitum dietary randomized controlled crossover trial. American Journal of Clinical Nutrition. 2026.
• Research published in 2025 examining the combined effects of eating rate and energy density on voluntary energy intake in healthy adults.
• Recent controlled research examining food texture, processing level, food reward, satiety and later energy intake.

This article is for general educational purposes only and is not medical advice. Nutrition, appetite and metabolism are influenced by many individual factors. If you have a medical condition, take medication or are considering a major dietary change, speak to an appropriately qualified healthcare professional.