Can a Healthy Diet Include Ultra-Processed Foods?

Almost nobody follows national nutrition guidelines.

In the United Kingdom, fewer than 0.1 percent of adults follow the government’s Eatwell Guide. In the United States, fewer than 5 percent of people meet recommendations for foods such as dark-green vegetables, orange vegetables, legumes, or whole grains.

Meanwhile, ultra-processed foods make up more than half of the average diet in many developed countries.

They are convenient, highly palatable, profitable, and unlikely to disappear unless society collectively decides it suddenly loves soaking beans overnight.

But ultra-processed foods are not nutritionally identical. The category includes soda, candy, and packaged pastries, but also high-fiber cereal, commercial whole-grain bread, flavored yogurt, protein products, and frozen meals engineered to meet nutrition guidelines.

So what happens when someone eats a diet made mostly from “healthy” ultra-processed foods?

Could low-fat frozen meals, fortified cereal, and nutritionally improved packaged snacks support health if the overall diet meets official recommendations? Or does processing still matter?

The UPDATE trial, a randomized crossover study conducted at University College London, was designed to find out.

The answer was surprisingly reasonable: Both diets helped, but the minimally processed diet helped more.

Research Reviewed

Researchers recruited 55 adults in the United Kingdom. Participants were 43 years old on average, 91 percent were women, and their average BMI was 32.7.

Their usual diets were already high in ultra-processed foods, providing approximately 67 percent of daily calories. Researchers were not dragging lifelong farmers away from their hand-ground oats and forcing them to eat frozen lasagna. The participants started fairly close to the typical British diet.

Each person completed two eight-week diets:

A minimally processed food, or MPF, diet

An ultra-processed food, or UPF, diet

The order was randomized, with a four-week washout period between them.

Both diets were designed to meet the United Kingdom’s Eatwell Guide recommendations for macronutrients, fiber, fruits, and vegetables.

The MPF diet emphasized whole or lightly processed ingredients. The UPF diet used nutritionally reformulated supermarket foods.

Meals were fully prepared, delivered to participants’ homes, and provided free. Participants could eat as much as they wanted, and researchers did not tell them that weight loss was the goal.

By the end, 50 people provided data for at least one diet and 43 provided data for both.

Both Diets Produced Weight Loss

Participants lost weight on both diets.

During the minimally processed phase, average weight fell by approximately 2 percent, compared with 1 percent during the ultra-processed phase.

That amounted to:

4.1 pounds lost on the MPF diet

1.9 pounds lost on the UPF diet

The MPF diet also produced more fat loss.

Participants lost approximately 3.5 pounds of fat during the MPF phase, accounting for about 85 percent of the total weight lost. During the UPF phase, they lost approximately 1.3 pounds of fat, or about 68 percent of the total loss.

Body-fat percentage dropped slightly more than one percentage point on MPF, compared with around 0.3 percentage points on UPF. Visceral fat fell about three times more during the MPF phase.

Lean body mass did not change significantly on either diet.

Participants Ate More Calories on the UPF Diet

Participants consumed approximately 327 more calories per day during the ultra-processed phase.

Nobody assigned those extra calories. They appeared naturally when participants ate according to appetite.

The UPF diet was more energy-dense, meaning it packed more calories into a smaller amount of food. Previous trials have also found that people tend to eat ultra-processed foods faster and chew them fewer times.

That combination can make it easier to consume more energy before the brain receives the memo that lunch has already happened.

Processing may not be the only explanation. Texture, flavor, convenience, eating speed, and food volume may all have contributed. But matching nutrients on paper did not eliminate the difference in how much people ate.

Health Markers Improved on Both Diets

Several cardiometabolic markers moved in a favorable direction.

Only triglycerides and LDL cholesterol differed significantly between diets.

Triglycerides improved more on the minimally processed diet. LDL cholesterol unexpectedly fell more on the ultra-processed diet.

The researchers did not offer a firm explanation for the LDL result. One possibility is that many nutritionally reformulated packaged foods contain less saturated fat and more added fiber, both of which can lower LDL cholesterol.

The UPF diet also appeared to win on heart rate, but the difference between diets was not statistically significant. That means it may have been noise rather than a genuine advantage—science’s polite way of saying, “Interesting, but don’t build a TED Talk around it.”

Overall, the results suggest that improving diet quality toward national recommendations can benefit health even when much of the food is ultra-processed.

The minimally processed version still produced greater weight loss, fat loss, blood-pressure reductions, and triglyceride improvements.

Appetite and Cravings Favored Minimally Processed Food

Participants also reported better control over eating during the MPF phase.

Compared with the UPF diet:

Savory-food cravings fell by about 11 additional points.

Difficulty resisting craved foods improved by about 14 points.

Craving control improved by approximately 12 points.

Scores measuring the psychological pull of food declined.

Participants showed trends toward greater fullness and less post-meal hunger.

That lines up with the calorie findings: People ate less while reporting better control over their appetite.

Nutritional labels can tell us how much fiber and protein a food contains. They cannot fully capture how quickly it disappears into someone’s face.

The MPF Diet Was Harder to Follow

The minimally processed diet produced better results, but adherence was lower:

85 percent adherence on MPF

91 percent adherence on UPF

Six participants dropped out during the MPF phase. None dropped out during the UPF phase.

Adherence also declined over time on both diets. It was approximately 92–93 percent during the first eight weeks and fell to roughly 79–87 percent during the final period.

That happened while researchers were delivering free, prepared food directly to participants.

In ordinary life, people also have to shop, cook, clean, work, travel, raise children, and occasionally stare into the refrigerator hoping dinner will reveal itself.

Convenience matters.

What This Means in Real Life

The UPF diet in this study was not built from soda, candy, chips, and pastries. Researchers intentionally selected foods that met national recommendations for nutrients, fiber, fruits, and vegetables.

That probably explains why participants still lost weight and improved several health markers.

This study therefore does not support treating every ultra-processed food as nutritionally equivalent.

A frozen meal containing lean protein and vegetables is different from a frozen dessert. High-fiber cereal is different from candy, even though both arrive in colorful boxes designed by people who know exactly where your eyes go first.

Useful questions include:

What nutrients does the food provide?

How calorie-dense is it?

Is it filling?

How quickly is it eaten?

What does it replace?

Does it make a nutritious diet easier to sustain?

A protein shake, packaged bread, frozen entrée, or high-fiber cereal may help someone meet nutrition targets during a busy week.

At the same time, the study suggests that a diet dominated by packaged foods may make passive overeating easier, even when those foods look respectable on the nutrition label.

You Do Not Need to Eliminate UPFs

Trying to remove every ultra-processed food is unnecessary for most people and can create a tremendous amount of work for fairly small returns.

Depending on the classification system, UPFs may include commercial bread, yogurt, protein powder, plant-based milk, ready-made sauces, and many frozen meals.

Processing is one characteristic of food. Nutrient content, calories, protein, fiber, portion size, enjoyment, and the overall dietary pattern matter too.

A reasonable approach is to build most meals around minimally processed foods while using convenient products intentionally.

Whole fruit, vegetables, legumes, potatoes, lean proteins, and minimally processed grains tend to provide more food volume per calorie. Packaged foods can fill the gaps when time, energy, or cooking enthusiasm is running low.

That balance gives people many of the appetite and health advantages of minimally processed food without requiring them to churn their own butter.

Closing Thoughts From Two Decades of Coaching

Nutrition discussions become far less useful when food is divided into morally pure and hopelessly toxic categories.

This study found that nutritional quality mattered. The carefully designed UPF diet improved body weight and several cardiometabolic markers.

Processing mattered too. Participants ate more calories, lost less fat, and experienced less improvement in cravings during the UPF phase.

For more than a decade, we have used an 80:20 approach with clients: roughly 80 percent of intake comes from minimally processed, nutrient-dense foods, while approximately 20 percent can come from more processed foods someone enjoys or finds convenient.

That ratio is not a law of physiology. Nobody’s liver carries a calculator and shuts down at 79 percent broccoli.

It is a practical guideline that has held up well enough for most people to maintain healthy body composition, blood pressure, blood sugar, cholesterol, and other health markers while still enjoying UPFs when they choose.

Some people will feel and perform better with a higher percentage of minimally processed food. Others need more convenience to make the plan sustainable. The appropriate balance depends on the person’s health, goals, appetite, preferences, schedule, and current habits.

The real target is a dietary pattern that supplies adequate protein, fiber, plants, nutrients, and manageable calories while leaving enough flexibility for someone to live a normal life.

Minimally processed foods should probably form the foundation.

Ultra-processed foods can still have a seat at the table. They just do not need to own the house.

References

Scheelbeek P, Green R, Papier K, Knuppel A, Alae-Carew C, Balkwill A, et al. Health impacts and environmental footprints of diets that meet the Eatwell Guide recommendations: analyses of multiple UK studies. BMJ Open. 2020;10:e037554.

Krebs-Smith SM, Guenther PM, Subar AF, Kirkpatrick SI, Dodd KW. Americans do not meet federal dietary recommendations. Journal of Nutrition. 2010;140(10):1832–1838.

Dicken SJ, Jassil FC, Brown A, Kalis M, Stanley C, Ranson C, et al. Ultraprocessed or minimally processed diets following healthy dietary guidelines on weight and cardiometabolic health: a randomized, crossover trial. Nature Medicine. 2025;31:3297–3308.

Hall KD, Ayuketah A, Brychta R, Cai H, Cassimatis T, Chen KY, 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(1):67–77.

Hamano S, Goto S, Katakami N, Atsumi A, Sato R, Kamitani M, et al. Ultra-processed foods cause weight gain and increased energy intake associated with reduced chewing frequency: a randomized, open-label, crossover study. Diabetes, Obesity and Metabolism. 2024;26:5431–5443.

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