Your Fruits and Veggies Are Losing Their Nutrients—Here’s Why

Here’s what you’ll learn when you read this story:

• The “green revolution” increased crop yields following World War II to feed an ever-increasing global population, but the nutritional value of those foods steadily declined over the decades.

• A new report warns of a possible “tipping point” where a food system stressed by climate change could imperil populations already on the brink of nutritional deficiency.

• Some methods, such as biofortification, can help raise the nutrition levels of fruits, vegetables, and grains, but scientists warn that it’s far from a perfect fix.

One of the first rules of healthy eating that most of us learn as children, often drilled into us by exasperated parents, is to “eat your fruits and vegetables.” But decades of evidence suggest these dietary staples are losing their nutritional punch.

Back in 2004, a shocking study analyzing 43 garden crops and poring over USDA food composition data from 1950 and 1999 found worrisome deficiencies across the board. Calcium declined by 16 percent, iron by 15 percent, and phosphorus by 9 percent. In some cases, crops had up to 38 percent less nutritional value than they did in the 1950s and 60s. So, what exactly happened?

As the BBC points out, wartime food shortages and a fast-growing global population drove the development and adoption of high-yield crop varieties. Farmers also adopted synthetic nitrogen fertilizers on a massive scale, along with a rapidly expanding arsenal of chemical pesticides. Known today as the “green revolution,” the gamble worked—at least on paper. Cereal yields, for example, saw a whopping 215 percent increase per hectare while only expanding land use by 15 percent, according to a new report by London-based Deep Science Ventures. But as the 2004 study discovered, the nutritional value of foods, whether iron, calcium, zinc, vitamin A and others, didn’t keep pace.

“Over the past two decades, there have been a series of isolated reports that have shown nutritional density may have declined by over 40 percent since the green revolution in specific crops and contexts,” the new report says. “Such a decline in nutritional density would mean you have to consume 67 percent more calories to reach the same nutritional outcomes—a response that is simply not viable because of the vital importance of a healthy weight and hence strict matching of calories to energy needs.”

This leads to a phenomenon known as “hidden hunger,” where someone feels sated on empty calories but isn’t getting enough nutrients. A 2024 study in the journal Foods reported that more than two billion people suffer from nutrient insufficiency and highlighted multiple reasons for this slipping decline in food quality. One of the main causes is the agriculture industry’s emphasis on high-yield crops, which often trade nutritional quality for sheer volume. Other studies have found that increased carbon dioxide levels due to climate change can also negatively impact crops. One such study in 2018 found that increased carbon dioxide levels reduces protein, iron, and zinc in rice crops.

Other causes for the nutritional decline include the continued use of insecticides, fungicides, and herbicides; the rise of processed foods; and the declining availability of nutrient-rich soils to farm in the first place.

“This creates a plausible tipping-point risk—degrading nutritional density while stripping away the masking effect of excess calories, with impacts that would be especially acute for people already near the margin of deficiency, including children, women of reproductive age, older adults and populations dependent on staple cereals,” the new report concludes.

Humanity has a few methods that could help boost nutritional values, though. Chief among them is “biofortification,” a series of technologies and techniques that put nutrients directly into plants to help ease hidden hunger. Biofortification can include making genetic modifications to the plants, developing nutrient-rich fertilizers, or selectively breeding whole new plants. The World Health Organization reports early successes with iron-biofortified rice, which was shown to improve iron levels in women and children in the Philippines and India, while vitamin A-biofortified sweet potatoes eased deficiencies in countries throughout Africa. However, some scientists have argued that biofortification is far from a perfect solution, since it can harm crop yields while promoting genetic uniformity, which can lead to devastating plant disease outbreaks.

Today, the old maxim still holds true—it’s still healthy to eat your fruits and vegetables. But it’s worth keeping in mind that, at least nutritionally speaking, these aren’t your grandparents’ veggies.