Mayonnaise isn’t bad for you in typical amounts. A tablespoon has about 100 calories and nearly 11 grams of fat, but most of that fat is unsaturated, the kind that supports heart health rather than undermining it. The real question is how much you’re using and what the rest of your diet looks like.
What’s Actually in a Tablespoon
A standard tablespoon of commercial mayonnaise (like Kraft) contains 98 calories, 10.6 grams of total fat, 1.62 grams of saturated fat, and 77 milligrams of sodium. That’s a calorie-dense food, no question. But most of the fat is unsaturated, split between polyunsaturated and monounsaturated types. Saturated fat, the kind most linked to heart disease, makes up a relatively small share.
Mayonnaise also delivers some useful micronutrients. A tablespoon provides meaningful amounts of vitamin E, an antioxidant that protects cells from damage, and vitamin K, which plays a role in blood clotting and bone health. These come from the oil base, not the eggs. You wouldn’t eat mayo for its vitamins, but they’re a legitimate bonus.
Where mayonnaise becomes a problem is portion size. Most people don’t stop at one tablespoon. A thick layer on a sandwich or a generous scoop in chicken salad can easily hit three or four tablespoons, pushing you past 300 calories and 40 grams of fat before you’ve added anything else to the meal. The food itself isn’t harmful. The way people use it often is.
The Soybean Oil Question
Most commercial mayonnaise is made with soybean oil, which has become a lightning rod in online health circles. Critics claim that soybean oil is loaded with omega-6 fatty acids that drive inflammation throughout the body. The clinical evidence doesn’t support this. Research published in the journal Nutrition found that soybean oil does not affect inflammatory biomarkers and does not increase oxidative stress.
The concern about the ratio of omega-6 to omega-3 fats sounds logical on paper, but major health agencies have consistently rejected the importance of that ratio. What matters more is getting enough of each type of fat, not obsessing over how they compare to each other. The Center for Science in the Public Interest put it plainly: the best evidence doesn’t show that soybean, canola, safflower, or sunflower oil causes inflammation or other problems.
Eggs, Cholesterol, and Your Heart
Mayonnaise contains egg yolks, which means it contains dietary cholesterol. For years, the conventional wisdom flip-flopped on whether dietary cholesterol matters. The current picture is more nuanced than either “eggs are fine” or “eggs are dangerous.”
Eating cholesterol-rich foods raises fasting blood cholesterol by about 10% on average, but individual responses vary widely. Some people see almost no change, while others see significant spikes. More importantly, dietary cholesterol amplifies the effect of saturated fat. If you’re eating mayo on a bacon sandwich, the combination raises LDL cholesterol more than either food would alone.
The 2015 Dietary Guidelines removed the specific cap of 200 to 300 milligrams of cholesterol per day, which generated headlines suggesting cholesterol no longer mattered. But the actual guideline said cholesterol intake should be “as low as possible” within a healthy eating pattern. That’s a far cry from a green light. In a tablespoon of mayo, though, the cholesterol contribution is modest. It becomes relevant only if you’re piling on large amounts or combining it regularly with other high-cholesterol foods.
Additives and Preservatives
If you flip over a jar of commercial mayonnaise, you’ll likely see calcium disodium EDTA on the label. This is a preservative that prevents the oil from going rancid and keeps the product shelf-stable. The FDA permits it in mayonnaise at up to 75 parts per million, a trace amount. At those levels, it has a long safety record and isn’t something worth worrying about.
Homemade Mayo Carries a Real Risk
Homemade mayonnaise uses raw egg yolks, and that introduces a genuine food safety concern. Mayonnaise made from contaminated eggs has been directly linked to outbreaks of Salmonella infections. Research confirms that Salmonella can survive the mayonnaise-making process, meaning the acid from vinegar or lemon juice alone isn’t enough to reliably kill the bacteria.
Interestingly, lemon juice performs slightly better than vinegar at reducing Salmonella populations during refrigerated storage. But neither eliminates the risk entirely. If you make mayo at home, using pasteurized eggs is the simplest way to avoid the issue. Commercial mayonnaise uses pasteurized eggs and is not a Salmonella concern.
Is Avocado Oil Mayo Healthier?
Avocado oil mayonnaise has exploded in popularity, often marketed as a premium, healthier alternative. It typically costs more than twice as much as standard mayo. But the nutritional advantage is essentially zero. All oils used in mayonnaise are largely unsaturated. Soybean oil actually has a slight edge because it’s richer in polyunsaturated fats, which lower LDL cholesterol more effectively than the monounsaturated fats found in avocado and olive oil.
If you prefer the taste of avocado oil mayo, that’s a perfectly fine reason to buy it. But paying a premium because you believe it’s healthier isn’t supported by the evidence.
How to Keep Mayo in Your Diet Sensibly
The simplest strategy is portion awareness. One tablespoon is enough to add flavor and moisture to a sandwich without turning a reasonable lunch into a calorie bomb. Measuring once or twice helps you calibrate what a tablespoon actually looks like, because most people significantly overestimate.
Light or reduced-fat mayonnaise cuts calories roughly in half, usually by replacing some of the oil with water and starches. The tradeoff is a thinner texture and sometimes more sodium or sugar to compensate for lost flavor. Whether that tradeoff works for you depends on what you’re using it for. In tuna salad or coleslaw where mayo is blended with other ingredients, most people can’t tell the difference.
For people watching saturated fat or cholesterol intake, mayo is a better choice than butter in most applications. Tablespoon for tablespoon, butter has roughly five times the saturated fat. Swapping butter for mayo on bread is one of the easier dietary upgrades you can make without sacrificing much in terms of taste or texture.