Are Vegetables Really as Healthy as We Think? An Expert Questions that Belief.

Vegetables on the plate – and we instantly feel healthier. That’s what we’ve always been taught: as kids, when we reluctantly ate our spinach, or as adults, when we follow nutrition advice to do something good for our bodies.

But now, our belief in vegetables might be shaken. A nutrition expert has made a statement that is causing a stir: There is no clear evidence that vegetables are as healthy as we think.

Studies Show Correlation, But Lack Proof

The assumption that vegetables are good for us isn’t baseless: Many studies show that people who eat a lot of vegetables tend to be healthier. However, nutrition scientist Uwe Knop points out that the actual evidence for the health benefits of vegetables is surprisingly weak. Does that mean eating vegetables has no advantages? It’s not that simple.

Nutrition Studies and their Limits

The reason it’s difficult to prove a causal link between certain foods and health outcomes lies in how nutrition studies are conducted. Unlike medicine, where medications are tested in controlled trials, dietary recommendations are usually based on observational studies.
The problem? These studies show only correlations – not causation. For example, people who eat a lot of vegetables often live healthier lives. But is that really because of the vegetables, or could it be due to other factors like exercise, non-smoking, or higher income? According to Knop, such studies cannot establish a clear cause-and-effect relationship. This leads to vague or even contradictory results. Other reasons include:

Lack of Randomization: In high-quality scientific studies, people are randomly assigned to groups to avoid bias. But with nutrition, that’s hardly feasible—no one would follow a prescribed diet for decades.

No Placebo Effect: In medicine, drugs are often compared with placebos to verify real effects. In nutrition research, there is no such thing as “placebo vegetables” or a “placebo diet.”

Unreliable Self-Reporting: Many studies rely on questionnaires where participants report their own eating habits. But people tend to exaggerate how healthy they eat—who wants to admit they eat fast food every day?

No Long-Term Studies with Hard Outcomes: While medical research includes studies on heart attacks, cancer, or life expectancy, nutrition scientists often have to rely on indirect markers like blood pressure or cholesterol levels. These are just snapshots and offer limited insight into overall health.

J- or U-Curve Effect: Studies often show that both very low and very high consumption of a particular food are linked to higher mortality. This makes clear recommendations difficult and complicates statements about dose-response relationships.

Should We Stop Eating Vegetables?

Of course not. Vegetables contain valuable nutrients, fiber, and antioxidants, which are associated with positive health effects. The key point is: Science has not yet been able to prove that vegetables alone are directly responsible for better health.

Variety on the Plate Instead of Superfoods

Nutrition is highly individual! What works for one person may not necessarily work for another. The effects of food depend heavily on lifestyle and environmental factors. If you want to eat healthy, don’t rely on individual "miracle foods"—instead, focus on a diverse and balanced diet.

No single food is a guaranteed health booster—but none is a standalone risk either.

Photo by markus spiske via Unsplash