Nearly all diets agree on one point.

This includes keto, vegan, paleo, Whole 30, Mediterranean, and Nordic diets, among others.

They all emphasize minimally processed foods and restrict ultra-processed foods.

Generally speaking, ultra-processed foods barely resemble their whole food origins and (usually) have minimal nutritional value. Plus, the more processed a food is, the more additives, such as sugar, refined starch, unhealthy fats, sodium, preservatives, and fillers, it usually contains.

These additives—especially sugar, fat, and sodium—are often combined to make foods highly palatable and rewarding or so delicious that they’re nearly impossible to stop eating.

Dozens of years of research indicate that ultra-processed foods lead to overeating, weight gain, and poor health.

A new study published in the British Medical Journal refutes none of the past research. It bolds and underlines everything we’ve long suspected.

Still, it’s worth knowing about for three reasons:

• It’s the most extensive study completed on the topic to date.

• The media is talking about it so that you might hear it randomly.

• In the US, 58 percent of the average person’s food intake comes from ultra-processed foods. Intakes in many other high-income countries are just as high. Translation: This is an area where most of us need some work.

How the Study Worked

The authors conducted an umbrella review—a review of reviews.

It’s considered one of the highest levels of evidence because it synthesizes data from systematic reviews and meta-analyses, which themselves synthesize results from previously published research.

It looked at 14 meta-analyses involving a whopping 9,888,373 study participants.

The paper examined associations between the consumption of ultra-processed foods and a range of health outcomes, including all-cause mortality and cancer, as well as mental, respiratory, cardiovascular, gastrointestinal, and metabolic health.

What the Study Found

The researchers found ultra-processed foods are linked to 32 harmful health effects, including type 2 diabetes, anxiety, mental health disorders, all-mortality, obesity, and cardiovascular disease mortality.

Takeaways

1. Every study has a weakness.

It’s tempting to assume that “the largest study in the world ever done” must be 100 percent true.

However, that’s not how science works.

Like all research, this study presents several strengths and weaknesses.

Among the strengths: The high number of participants, the pooled analysis of meta-analyses, and the meticulous statistical calculations all add to the study’s trust factor.

Among the weaknesses: The meta-analyses combined results mainly from observational studies—case-control, cohort, and cross-sectional—not randomized controlled trials (RCTs), which are the gold standard of research.

Observational studies collect data based on what people do in everyday life, without having them change anything or do anything specific. Importantly, these types of studies can’t show cause and effect.

2. It’s about what you eat most of the time.

In most cases, the scientists were comparing people who habitually eat the most ultra-processed foods to those who habitually eat the least.

In other words, those who had the worst diet quality were at higher risk for death, obesity, metabolic disease, mental disorders, and more compared to those who had the best diet quality.

That’s certainly not a big surprise to anyone. In fact, it’s exactly what you’d expect.

So even though the study findings may come off as “ultra-processed foods will kill you,” it’s not really about individual ultra-processed foods being “bad.”

Instead, it suggests the overall quality of a person’s dietary pattern is very important for good health, but that doesn’t mean eating some ultra-processed foods makes you unhealthy. (Example: We often tell people to strive for a diet that’s 80 percent minimally-processed.)

3. We classify ultra-processed foods differently from the researchers.

The researchers used something called the NOVA Food Classification System to sort foods into four categories:

• Unprocessed and minimally processed

• Oils, fats, salt, and sugar

• Processed foods, which include things like tomato sauce and fruits canned in syrup

• Ultra-processed foods like ice cream, fast food burgers, and chicken nuggets.

If you take a look at the NOVA system, you’ll likely have some questions.

For example, NOVA considers canned soup ultra-processed but canned tuna is just “processed.”

Similarly, sports drinks and presumably protein powders (based on the description) are considered “ultra-processed,” but it’s easy to imagine situations where those options are beneficial and perhaps even the best nutritional choice.

Most clients won’t find this classification system particularly useful. That’s why we sort foods differently into eat more, eat some, and eat less categories.

See our “What Should I Eat?” infographic for more on our approach, which ultimately emphasizes whole foods but makes room for ultra-processed foods you enjoy.

All the best,

Michael Beiter

Certified Personal Trainer

PN L1 Sleep, Stress Management, Recovery coach

References

1. Lane MM, Gamage E, Du S, Ashtree DN, McGuinness AJ, Gauci S, et al. Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses. BMJ. 2024 Feb 28;384:e077310.