“To say all processed food is bad is a mistake,” said Dariush Mozaffarian, the dean of Tufts University’s Friedman School of Nutrition Science and Policy, at a session before the Aspen Ideas Festival.
“I think it’s interesting, even the question ‘fresh versus processed’… as though they were opposites,” he said. “You can have something that’s fresh and processed and something that’s fresh and not processed.”
According to the Food and Drug Administration, what “fresh” means, legally, in the United States is this:
When used in a manner which suggests that a food is unprocessed, the term “fresh” means that the food is in a raw state and has not been frozen or subjected to any form of thermal processing or preservation, except:
- The addition of approved waxes or coatings;
- The post-harvest use of approved pesticides;
- The application of a mild chlorine wash or mild acid wash on produce; or
- The treatment of raw foods with ionizing radiation not to exceed the maximum dose of 1 kiloGray in accordance
Everything else is “processed.”
“If you make bread at home, that’s processed,” said Jorg Spieldenner, the head of the public-health nutrition department at Nestlé Research Center. “If you heat something, that’s processed. When you make an egg, that’s processed food. According to the definition.”
There are different levels of processing, as Mandy Oaklander wrote in Time when reporting on a recent study. A bagged salad would count as “minimally processed.” A single food that has just had something added to it, like oil or sugar, would be “basic processed.” “Moderately processed” foods have additives but are still recognizable in their true form as meat or vegetables or what have you. “Highly processed” foods are made of multiple ingredients, and there’s no way to know where anything originally came from. In the study, 61 percent of Americans’ calories came from highly processed foods, and 16 percent from moderately processed.
But if what you’re eating is fruits, vegetables, or meat, not a multi-ingredient, highly-processed mélange like Coca-Cola or Doritos, whether it’s technically “fresh” as opposed to frozen or canned is not really that important. In some cases, frozen could be better.
Take the example of purchasing a peach in winter in New England, where there are no fresh peaches locally.
“I would buy a frozen peach,” said Hugh Acheson, a chef and owner of four restaurants in Georgia. “The problem with the peach that was grown in Chile and then put in a refrigerated system and then put on a ship … is it was grown four months ago.”
In that case, the “fresh” peach may well have lost some of its nutritional value on the journey. Whereas if the frozen peach was frozen shortly after harvest, it probably retained more nutrients.
A review published in the Journal of the Science of Food and Agriculture concluded:
Depending on the commodity, freezing and canning processes may preserve nutrient value. While the initial thermal treatment of canned products can result in loss, nutrients are relatively stable during subsequent storage owing to the lack of oxygen. Frozen products lose fewer nutrients initially because of the short heating time in blanching, but they lose more nutrients during storage owing to oxidation. In addition to quality degradation, fresh fruits and vegetables usually lose nutrients more rapidly than canned or frozen products.
“Eat any peach versus no peach at all,” Mozaffarian said. “The main problem with the food supply is bad eating.” If people are eating fruits and vegetables, the health differences in how they’re prepared are “around the margins,” according to Mozaffarian.
He ended with a parable on the silliness of having skewed priorities when it comes to health.
“I’m a cardiologist,” he said, “and I had a patient come in once asking about salmon. He said, ‘I heard there’s PCBs in salmon. Should I be eating wild salmon or farmed salmon?’ I said, ‘Stop smoking.’”