We all know the health perks of eating more vegetables: A wealth of research has found diets rich in fruits and vegetables lower blood pressure, decrease risk of heart disease, can reduce blood cholesterol levels, and may offer protection against certain types of cancers.
But all that means just fresh vegetables, right? Frozen veggies must not be as nutritious as plants plucked straight off the farm. Well, not so fast, says science.
The Claim: Frozen Food Is Just as Good as Fresh
Research from the University of Georgia, funded by the Frozen Food Foundation, looked at the nutritional value of supermarket produce over the course of two years at various stages: when they were fresh; in the fridge for five days; and frozen. The Frozen Food Foundation selected the nutritional variables to look at as well as the produce (broccoli, cauliflower, corn, green beans, green peas, spinach, blueberries, and strawberries were studied).
The resulting study, published in the Journal of Food Composition and Analysis, found that all three methods of storing for the selected produce are generally nutritionally equal to one another.
Read more: Selected Nutrient Analyses of Fresh, Fresh-Stored, and Frozen Fruits and Vegetables from Journal of Food Composition and Analysis
The goal of the study, said corresponding author Ron Pegg, is to disprove the assumption that frozen produce is significantly less nutritious than fresh produce.
"There is a misconception out there that if you freeze [produce], you are losing the nutrients, the vitamins, and the minerals," says Pegg, who designed the study. "And that fresh is much better than the frozen. That is not the case at all."
One surprising finding, however, was that some frozen vegetables — like English green peas and green beans — actually offered higher levels of nutrients than their fresh counterparts stored in the fridge. Pegg, who calls the freezing process "Mother Nature's pause button," explains that frozen produce arrives at the processing plant "at the peak of ripeness." Because of this, sometimes produce has higher values of nutrition than what is found in the supermarket. Green peas, for example, have been found to lose 52 percent of their "wet weight" 24 to 48 hours after being picked.
"To us this is very intuitive, because the produce is taken at their peak ripeness and frozen right away," says Pegg.
Does This (Industry-Funded!) Claim Hold Up?
Now, we know what you're thinking. This study was funded by the frozen food industry itself. Are the results suspect? Can we trust them?
The best way to evaluate is to look at other, similar research. Science usually moves forward not in huge leaps and breakthroughs but through slow, iterative accumulation of research findings building on each other, after all. What do other studies say?
When it comes to frozen vegetables, other research does support much of this industry-funded study. A 2015 study from University of California Davis looked into the nutritional profiles (fiber, vitamins, minerals, etc.) of eight fresh and frozen fruits and vegetables — corn, carrots, broccoli, spinach, peas, green beans, strawberries, and blueberries — and found no significant differences between the fresh and frozen produce. According to lead author Ali Bouzari, whenever fresh or frozen produce had an edge over the other, it was "slight."
In other words, fresh and frozen are going to be quite similar in nutritional profile; the industry-funded study's findings that some frozen food had more nutrition is probably dependent on many variables. At the end of the day, there are marginal differences between fresh and frozen produce, and much of the disparities can be accredited to an array of external variables like what point in harvest is the produce frozen or how long fresh produce has been sitting out before being purchased — fresh produce can sometimes be traveling for weeks before it makes it to a grocery store.
"Frozen foods are not, by definition, less nutritious than fresh food," says Bouzari. "They can be, but it can also go the other way."
The Really Important Thing? Just Eat More Fruits & Veggies
While the exact amount of fruits and vegetables recommended for adults varies based on several variables (age, sex, and level of physical activity), the USDA's MyPlate — an updated advisory standard that replaced the food pyramid — recommends half a consumer's plate to be filled with fruits and vegetables. In a 2013 report, the Center for Disease Control found that 33 percent of American adults consumed less than one serving of fruits and veggies a day.
In this context, the consumer victory lies in eating fruits and veggies to begin with. "If you're eating fresh or frozen produce, in the grander scheme of making healthier choices, you've made one of the healthiest choices you can," says Bouzari.
"Something is better than none, but a combination of fresh and frozen — you can throw some canned and 100 percent fruit juice in there too — is best," says Marjorie Cohn, RD, CDN, and a national spokesperson for the Academy of Nutrition & Dietetics.
When it comes to fresh and frozen vegetables, there's a shifting trend among younger diners: According to The NPD Group, millennials and Gen Zs are responsible for the growth in fresh and frozen vegetable consumption. Specifically, those under the age of 40 have increased their annual intake of fresh veggies by 52 percent and frozen vegetables by 59 percent over the past 10 years.
In comparison, those 60 and older have decreased their consumption by 30 percent and 4 percent for fresh and frozen vegetables, respectively.
When it Comes to Fresh or Frozen, Flavor Is King
While the nutritional composition of fruits and vegetables may fluctuate, consumers can rely on a different scale when deciding whether to go frozen or fresh: flavor.
"A good litmus test and a good metric is the overall quality and deliciousness of produce," says Bouzari.
Cohn, on the other hand, recommends eating fresh produce when it's in season and not shying away from frozen alternatives. "My general rule of thumb is that if the fruit or veggie is in peak season, eat it fresh — it'll probably be more nutritious that time of year," he says. "For the rest of the year, simply try to get variety and more veggies and fruits overall. Peak season and local will likely always win out on the nutrient scale."