Ultra-Processed but Healthy? Lessons from Costa Rica

 What a 10-year, 125,000-person study reveals about plant-based diets

Costa Rica Series, Episode 3 · By Dr. Sean Wells, PT

You've heard it a hundred times, maybe even said it to your patients yourself: "Avoid ultra-processed foods." It's become one of the most repeated rules in nutrition, and even on our website material. But a large new study suggests the story is more nuanced, especially when it comes to plant-based eating.

For the third video in our Costa Rica series, we dug into research showing that people who ate a mostly plant-based diet had a lower risk of death and type 2 diabetes, even when some of those foods were ultra-processed. What mattered most wasn't the processing. It was the quality of the food.

PTs: want CEUs on this? See our nutrition series.

The study

Thompson and colleagues published this prospective cohort study in The Lancet Regional Health – Europe in 2026. The researchers followed 124,836 adults from the UK Biobank, aged 40 to 70 at the start, for roughly 8 to 10 years.

They asked a simple question: does the amount of ultra-processed food in a plant-based diet change its health benefits? To answer it, they scored each person's diet on two things at once:

• How healthy the plant-based pattern was. A healthy pattern leans on whole grains, fruits, vegetables, legumes and nuts. An unhealthy one leans on refined grains, sugary drinks and sweets.
• How much of it was ultra-processed, using the widely used Nova classification system.

What they found

People who stuck most closely to a healthy plant-based diet had an 8–28% lower risk of death from any cause and of developing type 2 diabetes. That was true whether their diet was high or low in ultra-processed foods.

The healthy plant-based pattern that included more ultra-processed foods was still linked to an 11% lower risk of cardiovascular disease.

The authors' conclusion: overall diet quality matters more than processing level for preventing chronic disease and lowering mortality.

One important caveat: this benefit showed up for healthy plant-based diets. A plant-based diet built on refined grains, sweets and sugary drinks is a different story. "Plant-based" alone isn't the goal.

Why quality beats processing: a lesson from Costa Rica

The researchers point to nutrients like fiber, protein and sugar as better markers of a food's value than whether it came out of a factory. Some ultra-processed foods still deliver real nutrition. Packaged whole-grain bread is a good example.

We see this every day in Costa Rica. Cow's milk isn't always easy to find, so many families rely on soy milk. Technically, most soy milk is ultra-processed. But it provides protein, fiber and other nutrients. As long as it isn't loaded with added sugar, it's a perfectly good choice.

This is a shift from how many of us, myself included, have talked about processed foods in the past. That advice wasn't wrong. Many ultra-processed foods are high in saturated fat, sugar and additives that can harm our health. But the label alone doesn't tell the whole story. Read the nutrition facts, not just the processing level.

What this means for PTs and our patients

As physical therapists and rehab professionals, we already know more fruits and vegetables are better for our patients. This study gives us a sharper, more practical message:

1. Ask "Is it high quality?" before "Is it processed?" Look for fiber, protein and low added sugar.
2. Don't demonize every packaged food. Whole-grain bread, canned beans and unsweetened plant milks can fit a healthy diet.
3. Watch for added sugar. It's the quickest way a "healthy" plant-based product turns unhealthy.
4. Keep the focus on whole plants. Fruits, vegetables, legumes, whole grains and nuts remain the foundation.
5. Make it realistic. Patients stick with advice that fits their budget, culture and what's on their store shelves, just like soy milk in Costa Rica.

The bottom line: go get your fruits and vegetables, and don't panic over every label that says "processed."