Yes, mayonnaise is a processed food. Even a basic homemade version involves combining and emulsifying ingredients that don’t naturally occur together. But the degree of processing varies enormously depending on whether you’re talking about a simple homemade blend, a clean-label store brand, or a mass-produced jar with a long ingredient list. Where mayonnaise lands on the processing spectrum matters more than the yes-or-no label.
How Food Processing Is Classified
The most widely used framework for categorizing food processing is the NOVA system, which sorts all foods into four groups. Group 1 covers unprocessed or minimally processed foods like fresh fruit, eggs, and plain meat. Group 2 includes processed culinary ingredients, things like oils, butter, sugar, and salt that are extracted from whole foods and used in cooking. Group 3 is processed foods, which are made by combining Group 1 and Group 2 items using methods like canning, fermenting, or bottling. Group 4 is ultra-processed foods, industrial formulations that typically contain additives you wouldn’t find in a home kitchen.
The distinction between Group 3 and Group 4 is where mayonnaise gets interesting. A jar with just oil, egg yolks, vinegar, salt, and maybe mustard fits comfortably in Group 3. A jar with modified food starch, calcium disodium EDTA, xanthan gum, and sugar starts looking more like Group 4.
What’s Actually in Store-Bought Mayo
Under U.S. federal regulations, a product labeled “mayonnaise” must contain at least 65% vegetable oil by weight, an acidifying ingredient (vinegar, lemon juice, or lime juice), and an egg yolk-containing ingredient. Those are the non-negotiable basics. Beyond that, manufacturers have room to add stabilizers, preservatives, sweeteners, and flavor enhancers.
Regular full-fat mayonnaise from major brands tends to have a relatively short ingredient list: soybean oil, eggs, vinegar, salt, and sometimes a preservative like calcium disodium EDTA to protect flavor. Light or reduced-fat mayonnaise is a different story. Cutting the oil means the emulsion needs help holding together, so manufacturers add modified food starch, sugar, gums, and other additives not found in regular mayo. The fewer calories on the label, the more processing typically went into the jar.
How Factory Mayo Gets Made
Industrial mayonnaise production involves steps that go well beyond whisking in a bowl. Egg yolks are first pasteurized at 65 to 75°C to kill bacteria while preserving lecithin, the natural emulsifier that holds the sauce together. Oil is then added slowly and broken into microscopic droplets by powerful rotor-stator systems inside vacuum processing units. The controlled speed of oil addition and the high shear force applied are critical to keeping the emulsion stable.
This is fundamentally different from what happens when you make mayo at home with a whisk or immersion blender. The industrial process creates a more uniform, shelf-stable product, but it also qualifies the result as more heavily processed by any reasonable definition.
The Oil Question
Most commercial mayonnaise uses refined soybean or canola oil, which undergoes its own significant processing before it ever reaches the mayo factory. Refining strips away compounds that would shorten shelf life but also removes beneficial nutrients. Cold-pressed oils retain roughly 25% more vitamin E (tocopherols) than fully refined versions, and refined oils can contain small amounts of trans fatty acid isomers (around 1.1% for linoleic and linolenic acids) that cold-pressed oils lack entirely. The refining process removes about 41% of tocopherols on average.
This doesn’t make refined oil dangerous, but it does mean the oil in most commercial mayo is itself a processed ingredient, adding another layer to the overall processing picture. Mayonnaise brands marketed as “made with avocado oil” or “made with olive oil” sometimes use higher-quality oils, though it’s worth checking labels since some blend a small amount of premium oil with a larger proportion of refined soybean oil.
Homemade vs. Commercial: A Real Difference
Homemade mayonnaise is oil, egg yolk, acid, salt, and maybe mustard. That’s it. You can make it in under five minutes. It’s processed in the same way that vinaigrette or pesto is processed: you’re combining and transforming whole ingredients. It won’t last more than a week in the fridge, which is actually a sign of how little has been done to it.
Commercial mayonnaise needs to survive months on a shelf and maintain the same texture from jar to jar, batch to batch. That consistency requires industrial emulsification equipment, pasteurization, preservatives, and sometimes stabilizers like modified starch. Modified starch treated with octenyl succinic acid, for instance, acts as both a thickener and an emulsifier, doing double duty that wouldn’t be possible with any ingredient you’d find in a home pantry. These additions are what push many store-bought varieties into the ultra-processed category.
Where Mayo Fits in Dietary Guidelines
The 2025 Dietary Guidelines for Americans specifically recommend avoiding “highly processed packaged, prepared, ready-to-eat, or other foods that are salty or sweet.” Mayonnaise isn’t singled out by name, and a condiment used in tablespoon-sized portions carries different implications than, say, a bag of chips or a sugary cereal you eat by the bowl.
The practical concern with mayonnaise is less about additives and more about calorie density. At 65% oil minimum, regular mayo packs a lot of energy into a small serving. If you’re using it as a thin spread on a sandwich, the processing level is probably less important to your overall health than the rest of your diet. If you’re mixing half a cup into a pasta salad, the calories and refined oil add up quickly regardless of brand.
Choosing a Less Processed Option
If minimizing processing matters to you, the simplest approach is checking the ingredient list rather than the front label. Look for mayo with five or fewer ingredients: oil, eggs, vinegar or lemon juice, salt, and mustard. Brands that use avocado oil or expeller-pressed oils skip some of the refining steps applied to conventional soybean oil. Avoid light or reduced-fat versions if processing is your concern, since they consistently contain more additives than their full-fat counterparts.
Making your own is the least processed option of all, and it takes about as long as reading this article. A cup of oil, one egg yolk, a teaspoon of acid, a pinch of salt, and an immersion blender will give you fresh mayonnaise with zero industrial additives. The tradeoff is a shorter shelf life and slightly less uniform texture, which for most people is a perfectly reasonable deal.