"Processed food" has become a catch-all term for foods we're told to avoid, but food processing isn't automatically a bad thing.

Technically, many foods you probably enjoy regularly are processed. Frozen vegetables, canned beans, yogurt, nut butter, and whole-grain bread have all been changed from their original state in some way.

So when research links processed foods to certain health concerns, it's important to understand what kind of processing we're talking about.

Much of the recent research has focused specifically on ultra-processed foods (UPFs). Diets containing large amounts of these foods have been linked to a range of negative health outcomes, including digestive and metabolic health issues, inflammation, and heart disease.

This article will review what we know so far and give you tips for including more whole foods in your diet.

Processed vs. Ultra-Processed Foods: Understanding the Difference

In food and nutrition research, a system called the NOVA classification is often used to group foods according to the type and extent of processing they undergo.

Minimally processed foods include fruits, vegetables, eggs, milk, and plain grains that may have been washed, frozen, pasteurized, dried, or otherwise prepared without significantly changing them from their original state.

Processed foods are generally made by adding ingredients such as salt, sugar, or oil. Examples include canned vegetables, cheeses, or freshly made breads.

Finally, ultra-processed foods are industrial formulations containing ingredients or additives not typically used in home cooking. Examples include many sodas, packaged snacks, instant noodles, candies, and some ready-to-eat meals.

This distinction is important because simply avoiding all processed foods would mean missing out on many convenient and nutritious options (such as canned beans and vegetables).

It's also important to recognize that there's considerable variation among foods categorized as UPFs. For example, a packaged whole-grain bread and a soda may both meet the criteria for ultra-processing under the NOVA classification, despite having very different nutritional profiles. 

Instead of deciding not to eat a food simply because it's processed, it can be more useful to look at the bigger picture and consider what nutrients the food provides and how it fits into your overall diet.

How Can Ultra-Processed Foods Affect Digestion?

While we're still uncovering exactly how UPFs affect the digestive system, one possibility is that they lack fiber.

Some diets high in UPFs are lower in naturally fiber-rich foods like fruits, vegetables, whole grains, beans, lentils, nuts, and seeds. You probably know fiber is important for staying regular, but certain types of fiber (known as prebiotics) act as food for the beneficial bacteria living in your gut. A diet lower in fiber may therefore affect both digestion and the health of your gut microbiome. 

There's also research currently examining the effects of common additives found in UPFs, such as certain emulsifiers and artificial sweeteners. However, most of the research linking these additives to negative effects on the gut microbiome and intestinal barrier has been conducted in vitro (test tube) or animal studies, so more research is needed before we can confirm whether these additives are harmful in humans.

Finally, some studies have found links between UPF intake and certain gut conditions. For example, a large systematic review and meta-analysis found that higher UPF consumption was associated with an increased risk of developing Crohn's disease.

However, there's still a lot we don't know about how UPFs impact gut health, and more research in humans is needed to understand which food components or other dietary factors may be responsible.

UPFs and Inflammation

Chronic, low-grade inflammation has been linked to the development of several chronic diseases, prompting researchers to investigate whether diets high in UPFs could contribute to inflammation.

Here are a few possible explanations:

• A diet high in UPFs may contain fewer foods rich in fiber, vitamins, minerals, and phytochemicals, which are associated with better overall diet quality.
• A diet high in UPFs can also contribute significant amounts of refined carbohydrates, saturated and trans fats, sodium, or added sugars.
• Certain ingredients in UPFs may alter the gut microbiome and promote gut inflammation.

However, much of the evidence connecting UPF intake with inflammation and chronic disease is observational. Studies like these can identify patterns, but they can't always tell us whether UPFs specifically are responsible or whether other differences in diet and lifestyle contribute to the association.

UPFs and Overall Health

The research on UPFs becomes more conclusive when we zoom out to consider overall health.

A 2024 umbrella review published in The BMJ found that higher exposure to UPFs was linked with increased risk across several health outcomes, with some of the strongest evidence involving heart disease, type 2 diabetes, mental health outcomes, and overall death rates.

However, it's important to note that the quality of the studies included in the review varied considerably. Only four of the 45 studies they reviewed received a moderate-quality rating; most were rated low or very low quality.

That said, there is some experimental evidence to consider. A small but well-controlled study of 20 adults found that those eating UPFs consumed an average of 500 additional calories per day and gained about 2 pounds. They lost a similar amount of weight when eating the minimally processed diet. The study showed that something about the UPF dietary pattern encouraged greater calorie intake, but it couldn't identify exactly which UPF component was responsible.

Do You Need to Stop Eating UPFs?

UPFs can provide valuable nutrients, and all foods classified as UPFs are not nutritionally identical. Instead of trying to eliminate all foods that qualify as UPFs, consider your overall dietary pattern. For example:

• Are you including fruits and vegetables throughout the day (fresh, frozen, or canned)
• Are you choosing whole grains and other fiber-rich foods regularly?
• Do you include beans, lentils, nuts, and seeds in your diet?
• Do you compare packaged foods based on what nutrients they actually provide rather than assuming that processing alone determines their nutritional value?
• Do you use convenience foods like canned beans and vegetables to make balanced meals easier, rather than feeling overwhelmed trying to prepare everything from scratch?

If UPFs currently make up a large portion of your diet, you don't need to overhaul everything overnight. Instead, try adding more minimally processed, nutrient-dense foods alongside the foods you already enjoy.

The Bottom Line

Food processing exists on a spectrum, and processed doesn't automatically mean unhealthy.

Research suggests that diets high in UPFs are associated with several health concerns, but researchers are still working to determine why these associations exist and whether all foods classified as UPFs carry the same risks.

Rather than fearing individual foods, focus on your overall dietary pattern. A diet built around a variety of fiber-rich plant foods, adequate protein, and nutrient-dense choices can still leave room for the occasional UPFs.

If you need help incorporating more whole foods into your diet, a dietitian can help. Click here to book an appointment with us at Blue Tree Nutrition.