What Does “Clean” Really Mean?

You wouldn’t want to eat or drink anything dirty, right? That’s why you wash your produce before you cook it, and why you’d never choose a torn-open bag of potato chips from off the supermarket floor. But when you see “clean” on a label in the grocery store, “free of dirt and dust” is almost definitely not what’s implied.

Last summer, Cameron Diaz launched a “clean” wine brand called Avaline that is...pretty much just normal wine. The brand received some mockery from wine writers, but since July, it’s sold more than 20,000 cases and is now available in four varieties. As more labels try to capitalize on Avaline’s success, Food & Wine recently published a story on the “cleanwashing” of wine that draws a connection to the similarly murky definition of “natural,” another trendy wine category that’s been growing by leaps and bounds.

In the last few years, lots of other products far beyond wine—from granola to skin cream—have started bragging that they’re “clean,” too. That certainly sounds like a good thing, but what does it actually mean?

The FDA has extensive rules about certain words on labels and in advertising for food and drugs: “Gluten-free” products must contain less than 20 parts per million of gluten; “organic” foods have to be certified by the USDA or one of several other independent organizations around the world;  “non-alcoholic” beers and wines must have less than .5 percent alcohol by volume (while “alcohol-free” items cannot contain any detectable alcohol whatsoever); and to be labeled free of “tree nuts,” one of the FDA’s “Big 8” food allergens, a product cannot contain any of 19 specific types of nuts that are spelled out species by species.

“Clean,” on the other hand, has no such definition. If you see the word on a package or in an ad, it carries exactly zero legal meaning. And even within the food industry, there’s nothing approaching consensus about what the word means. Is this just a marketing ploy intended to snag a certain type of (goopy, for lack of a more perfect word) consumer?

To try to clean things up (I’m very sorry), I reached out to four different food brands* that label themselves “clean” with two simple questions: 

• How does your brand define “clean”? 
• What is a specific “dirty” ingredient that your product doesn’t use, and why is it bad?

*Though all the brands quoted here responded to my questions on the record, I’ve chosen not to name them. Many, many brands call themselves clean and make similar misleading or outright untrue claims, and it seems unfair to single out the ones that took the time to respond to me.

To help interpret the responses, I enlisted the help of perhaps the world’s most eminent nutritionist: Dr. Marion Nestle. An award-winning author and Paulette Goddard Professor of Nutrition, Food Studies, and Public Health, Emerita at New York University, Nestle has taught biochemistry, nutrition, and public health for more than four decades.

Nowhere is “clean” more clear than when brands talk about “chemicals.” If you’ll remember high school science class, literally all of matter is chemicals. Water is a chemical. The air you breathe is a mixture of different chemicals. The only place there are truly no chemicals is in the cold, dead vacuum of outer space. So when a non-dairy yogurt company told me “human bodies are not designed to digest chemicals,” scientifically, it was just utter nonsense.

Two of the other brands that responded to my queries—a canned cocktail brand and a non-alcoholic canned seltzer brand—both cited hard-to-pronounce ingredients as examples of what’s “dirty” in other products. Just as being a “chemical” isn’t automatically concerning, there’s also absolutely no connection between an ingredient having a tough-to-pronounce name and it being dangerous. Isoamyl acetate is a flavor molecule found in bananas. Dihydrogen monoxide (DHMO), a molecule that’s fatal if inhaled, is just water, as this satirically insane website points out.

In many ways, the language of “clean” is the language of fear. The most initially concerning response I got to my questions came from that non-dairy yogurt brand. Two of the “dirty” ingredients it does not use are “xanthan gum, E415, invented in 1962 for a binder for toilet bowl cleaners and other household cleaners. Highly laxative effect,” and “guar gum, E412, patented by Kelco Co in 1975. Used in fracking.”

Terrifying, right? Nobody would want to eat something used in toilet bowl cleaners or fracking! And those industrial-sounding E-numbers! Well, those numbers are food additive codes assigned by the European Food Safety Authority (EFSA), and they specifically identify food additives that are safe and legal for use in food in the EU. Xanthan gum and guar gum are both thickeners you might find in dairy products or gluten-free baked goods; the former is made by bacterial fermentation of sugars, and the latter comes from a bean grown as food for humans and cattle in South Asia for centuries. (Xanthan gum is indeed used in toilet bowl cleaner, and guar gum is indeed used in fracking; water is also used in both.)

“I think food is one of life’s greatest pleasures, and it breaks my heart that people fear it,” says Nestle. But she says there is a grain of truth in some of this: A lot of what “clean” brands have in mind when they use the word is another term with a more specific meaning in the public health field—“ultra-processed.”

Think of it this way, explains Nestle: Corn on the cob is unprocessed, canned corn is processed, and Doritos are ultra-processed. “It’s an important term because we now have a NIH-controlled clinical trial showing that volunteers in a metabolic ward consume more calories when they are given ultra-processed foods and, therefore, gain weight.” The problem is that you can’t narrow down ultra-processed-ness to a single artificial ingredient or group of ingredients. “We don’t eat them on their own; we eat them in foods,” says Nestle. “The health effects depend on the foods. You can’t assess their effects separately from the foods that contain them.”

The most specific and straightforward definition of “clean” that I got came from a granola company: “Whole, minimally processed ingredients that are free of dairy, soy, refined sugars/flours, inflammatory oils, weird additives, or artificial ingredients." Besides “weird additives” (which sounds a lot like “chemicals”), this list is fairly clear. And it aligns with the USDA dietary guidelines on eating whole grains and cutting down on refined sugar, as well as Nestle’s advice to avoid ultra-processed food.

The problem is, it doesn’t align with science on the rest. Those same USDA dietary guidelines also include oils on a list of key recommendations for healthy eating patterns, and they say most Americans don’t eat enough dairy. By inflammatory oils, “I am guessing that [the company means] highly unsaturated vegetable oils high in omega-6 fatty acids,” says Nestle. “These are claimed to cause inflammatory reactions, but I’m not seeing much compelling research to back up this idea. Some people avoid dairy foods for reasons that also lack experimental proof. Others avoid soy, also for unproven reasons.”

“Clean” sounds perfectly innocuous on its own, but in fact, obsession with “clean” or “healthy” eating has been proposed as a new type of eating disorder called orthorexia. One of the main symptoms is cutting out large groups of foods and labeling them as unhealthy (or, say “dirty”)—it’s an all-or-nothing proposition, not a limit-your-consumption one.

Yet food companies continue to recommend doing exactly that by labeling certain ingredients “unclean” and “scary.” Why? A study by a group of academics at the University of Delaware that looked at “absence labeling”—advertising products as having an absence of something bad, as opposed to the presence of something good—found that it “can stigmatize food produced with conventional processes even when there is no scientific evidence that they cause harm, or even that it is compositionally different.” In other words, calling something “clean” is an effective way to turn people off of whatever doesn’t have the “clean” label, whether it’s “dirty” or not. “I think there is plenty of evidence that this works on lots of people,” says Nestle. Is it an ethical way to sell food? “No, of course not,” she adds, “but it is legal.”

So to come clean about all of this: Keep eating your dirty food. The people selling you clean food are using a dirty trick.