Are All UPFs Equally Bad For Health?

Ultra-processed foods (UPFs) are rarely out of the headlines.

Research shows that eating high levels of these highly industrially processed foods is linked to poorer health outcomes, including cardiovascular disease, type 2 diabetes, and obesity.

Understandably, the public is confused about UPFs, what the term means, and whether they need to worry about it.

In this article, we explain the state of scientific understanding and, importantly, how ZOE is helping: We’ve designed ZOE’s Processed Food Risk Scale to help people understand the true health risks linked to processed foods.   

We’re currently working hard to bring this new tool to the ZOE product and make it widely available.

How are UPFs currently classified?

Most commonly, experts rate how processed a food is using the NOVA classification framework. This method classifies foods into four groups:

• Group 1: Unprocessed or minimally processed foods.

• Group 2: Processed culinary ingredients.

• Group 3: Processed foods.

• Group 4: Ultra Processed Foods (UPFs).

First outlined in 1990, NOVA classifies “all foods according to the nature, extent, and purposes of the industrial processes they undergo.” 

Although widely used over the past few decades, NOVA has some limitations:

Why the confusion?

When scientists look at the consumption of NOVA category 4 foods in large populations, the overall effect is negative — those who eat the greatest amounts have the poorest health outcomes. 

These negative health effects are likely due to many factors, including: 

1. Chemical additives, such as colorants, emulsifiers, and preservatives. We still don’t know how these compounds influence the gut microbiome, but it’s likely that they have some effect.

2. UPFs often have high levels of energy, sugar, saturated fats, and salt. When consumed liberally, all of these components can negatively influence health.

3. UPFs are often energy-dense and scientifically crafted to be delicious and very easy to eat (hyperpalatable), making it very easy to take in excess energy very quicky. You could wolf down five ultra-processed brownies in the time it would take you to eat a single apple, for instance. 

4. Eating more of these convenient, processed foods could be displacing healthier whole foods that we should be eating more of.

Some UPFs tick all of these boxes while some may only tick one, despite their high level of processing.

This makes defining the health effects of any given UPF more challenging than it first seems.

Next, we’ll look at some recent studies that investigate how different forms of UPF influence health.

UPF types and heart health

A recent study analyzed dietary and heart health information from more than 200,000 people in the United States. Overall, they found that total UPF intake was linked to poorer cardiovascular health.

This finding aligns with previous research into links between UPFs and health. But when the scientists divided UPFs into categories, the story became more complex.

Some UPFs were associated with higher cardiovascular risk, including:

However, other UPFs were linked to a reduced risk of cardiovascular disease, such as:

An earlier study produced similar results. Overall, the scientists found that each extra serving of UPFs per day was associated with a 7% increase in cardiovascular disease risk. 

But when they analyzed UPF type seperately, once again, they found that processed meat and artificially sweetened beverages were associated with increased risk, while ultra-processed breakfast cereals were linked to reduced risk.

Similarly, a study involving people with cancer showed that those who consumed the most UPFs were more likely to also have cardiometabolic diseases, such as heart disease and diabetes.

UPF types and diabetes

In 2023, scientists published a study including data from almost 200,000 people. This time, they assessed UPFs’ links to type 2 diabetes.

Compared with those who consumed the lowest levels of UPFs, those consuming the highest amounts had a 46% increased risk of developing type 2 diabetes during the study follow-up.

Once they drilled down into UPF types, a familiar picture emerged. Associated with increased diabetes risk were:

However, some UPF categories were associated with lower diabetes risk:

• cereals

• dark and whole-grain breads

• packaged sweet and savory snacks

• fruit-based products

• yogurt and dairy-based desserts

Once again, some foods were linked to increased risks:

But some were linked to lower risk:

Why the difference between UPFs?

Of course, the next question is, why is there a difference between UPF types? The factors we outlined at the start of this article are likely important.

For instance, sugar-sweetened beverages and processed meat are reliably linked to poorer health outcomes.

These products are almost always high in sugar or salt and saturated fats, all of which are linked to health problems regardless of processing.

The NOVA classification system has proven useful for researchers, but it was designed to classify foods by their level of processing, not their impact on health. 

As the public becomes increasingly aware of processed foods and their links to health, we need an updated system that can capture the impact which processing can have on health — whether positive or negative. That’s where ZOE comes in.

Developing the ZOE Processed Food Risk Scale

ZOE’s Processed Food Risk Scale takes into account a number of factors that likely play an important role in how UPFs influence health:

• Energy density: How many calories per gram of food.

• Energy intake rate: How quickly you eat the calories.

• Hyperpalatability: This can lead to excess consumption.

• Non-culinary additives: These include artificial colors, sweeteners, and preservatives. We accounted for whether the European Food Safety Authority (EFSA), the Food and Drug Administration (FDA), or other official bodies deem them neutral or harmful.

ZOE’s scientists analyzed data from our PREDICT studies to calculate how much energy people derive from hyperpalatable foods and how energy-dense their foods are on average.  

They analyzed data from 891 people aged 34–58 years and found that these foods account for a large portion of people’s regular diets:

• 56% of foods were classed as energy-dense.

• 52% were hyperpalatable. 

• 38% were both energy-dense and hyperpalatable.

The ZOE Processed Food Risk Scale provides a new way to assess the likely health impact of processed foods. And it provides the level of risk in five simple categories:

• Unprocessed: This food is in its original form or close to its original form. Processing does not impact how healthy it is.

• No Risk: Minimal processing that poses no risk to health.

• Low Risk: The processing of this food has no or very low impact on its health. 

• Significant Risk: The processing of this food may make it less healthy and could have a moderate impact on your health. 

• Highest Risk: The processing of this food makes it less healthy and could have a high impact on your health.

Instead of a blanket penalty for all processed foods or penalizing foods based on the level of processing alone, ZOE’s new classification system will help people make sense of the food they’re choosing in their weekly shop.

We’re currently working behind the scenes getting ready to release it to the public. Watch this space.

Currently, “UPF” is a blanket term covering a vast range of products. Using the ZOE Processed Food Risk Scale will help you cut through the confusion and make better food choices every day.