Yes. A standard tablespoon of full-fat mayonnaise has about 90 to 100 calories, 10 to 11 grams of fat, and less than 1 gram of net carbs. That macro split lines up well with a high-fat, low-carb ketogenic diet. The exception is “light” mayo and anything with added sugar, so it’s worth reading the label before you buy.
About 5% of U.S. adults follow a ketogenic diet in a given year, and mayonnaise earns a permanent spot in most of their fridges. It adds fat without adding carbs, and it turns plain low-carb food (tuna salad, deviled eggs, lettuce-wrapped burgers) into something you’d actually want to eat. Below is the full nutrition breakdown, where mayo can quietly work against you, and how to choose or make a jar that keeps you in ketosis.
Why Mayonnaise Works So Well on Keto
Ketosis is a metabolic state where your body burns fat for fuel instead of glucose. To get there and stay there, most people following keto for weight loss or metabolic health aim for roughly 70 to 80% of daily calories from fat, 15 to 20% from protein, and 5 to 10% from carbohydrate, which usually works out to somewhere between 20 and 50 grams of total carbs a day. The stricter clinical version of the diet, originally developed to treat epilepsy, pushes fat even higher, up to 90% of calories, with carbs capped around 4%.
Mayonnaise is built almost entirely from oil and egg yolk, so its calories come overwhelmingly from fat, with barely a trace of carbohydrate. That’s a rare combination. Most sauces and dressings need some starch, sugar, or flour to thicken, and any of those adds carbs. Mayo gets its thickness from emulsification (whisking oil into egg yolk until it binds), not from carbohydrate. That’s exactly why it fits keto macros better than almost any other condiment in the fridge.
Mayonnaise Nutrition Facts, Per Tablespoon
Figures below are for regular, full-fat mayonnaise made with whole eggs, based on USDA FoodData Central values. Brands vary slightly, so check your specific jar.
| Nutrient | Per 1 tablespoon (~14g) |
|---|---|
| Calories | 90 to 100 |
| Total fat | 10 to 11g |
| Saturated fat | ~1.5 to 2g |
| Net carbs | 0 to 1g |
| Protein | ~0.1 to 0.2g |
| Cholesterol | ~5mg |
Two things stand out here. First, the carb count is close enough to zero that most labels round it down, which is why some jars list “0g carbs” and others list “1g.” Second, only a small slice of mayo’s fat is saturated. The rest is monounsaturated and polyunsaturated fat, mostly from whichever oil the brand uses. That matters more than people think, and we’ll get to why in a minute.
The Keto Mayo Trap: What’s Actually in the Jar
Regular mayonnaise is keto-friendly. “Light,” “reduced-fat,” and “fat-free” versions often aren’t, and that trips people up constantly.
When manufacturers strip fat out of mayo, they have to replace it with something to keep the texture creamy. That something is usually modified food starch, sugar, and sometimes maltodextrin. Hellmann’s Light Mayonnaise, for example, lists water, soybean oil, modified food starch, sugar, and vinegar ahead of the eggs on its ingredient label. Swapping real mayo for a “light” version to save calories can end up adding carbs, which is the opposite of what you want on keto.
A quick label checklist before you buy:
- Carbs per serving: Should be 0 to 1 gram. Anything higher usually means added starch or sugar.
- Ingredient list: Look for oil, eggs or egg yolks, vinegar or lemon juice, and salt, maybe mustard. Be cautious if starch, maltodextrin, or sugar shows up in the first five ingredients.
- “Light” or “reduced-fat” labeling: Treat it as a red flag until you’ve checked the carb count yourself.
- Miracle Whip: It isn’t legally mayonnaise. It’s classified as a “salad dressing” because it uses less oil and adds sugar and starch to compensate, which pushes its carb count well above regular mayo. Skip it on keto.
Does the Type of Oil Matter? The Seed Oil Question
Under federal rules, mayonnaise has to be at least 65% vegetable oil by weight to legally carry the name. Most major U.S. brands use soybean or canola oil because it’s cheap and neutral-tasting. Both belong to a group commonly called “seed oils.”
Seed oils have become a genuinely contested topic in nutrition circles. U.S. Secretary of Health and Human Services Robert F. Kennedy Jr. and other public figures have argued they drive inflammation and chronic disease, and the debate has gotten significant national media attention. Mainstream nutrition researchers are less alarmed. Reporting on the underlying science has found the evidence for a strong seed-oil-to-disease link is thin, and Cleveland Clinic dietitian Teresa Eury has pointed out that the bigger concern is usually the ultra-processed foods seed oils tend to show up in, not the oil itself.
None of that changes whether mayo is keto-friendly. Ketosis is about carbs, not oil source, and soybean oil mayo has the same near-zero carb count as olive oil mayo. If you’d rather avoid seed oils for other reasons, avocado oil and olive oil mayo (Primal Kitchen and Sir Kensington’s both make widely available versions) cost more but work exactly the same way on keto. Making your own at home is the only way to control the oil completely, which we cover below.
What About Cholesterol and Saturated Fat?
Mayo is egg-yolk-based, so it’s fair to wonder whether it’s going to wreck your cholesterol. Short answer: probably not, for most people.
The 2025-2030 Dietary Guidelines for Americans no longer set a specific daily cholesterol limit, a shift that lines up with newer research on eggs. A 2025 randomized trial in the American Journal of Clinical Nutrition found that saturated fat, not dietary cholesterol, was what actually moved LDL (“bad”) cholesterol in the people studied. Cleveland Clinic preventive cardiology dietitian Julia Zumpano makes the same point about eggs generally: total saturated fat intake affects LDL more than dietary cholesterol does.
That’s genuinely good news for mayo. Look back at the nutrition table above: only around 1.5 to 2 grams of mayo’s 10 grams of fat is saturated. The rest is unsaturated fat from the oil, which current guidance treats far more favorably. The American Heart Association generally recommends keeping saturated fat under about 10% of daily calories (lower if you’re managing high LDL), and a tablespoon or two of mayo is a minor contributor next to butter, bacon, or fatty cuts of meat, all of which are far more saturated-fat-dense.
If you have existing high cholesterol or heart disease, talk to a doctor before making any high-fat diet a regular habit, keto included. General guidance for the average dieter doesn’t automatically apply if you have a diagnosed condition.
Will Mayo Kick You Out of Ketosis?
Not from a normal serving. A tablespoon or two of mayo contributes somewhere between 0 and 2 grams of net carbs, which is a rounding error against a daily allowance of 20 to 50 grams. You’d need to eat an implausible amount of mayo in one sitting to move the needle on ketosis through carbs alone.
The more realistic way mayo derails keto isn’t carbs. It’s calories. At roughly 95 calories a tablespoon, it’s easy to stir a quarter-cup into a batch of “keto” coleslaw or chicken salad without noticing, and that adds up fast if you’re also watching total calories for weight loss. Being in ketosis and being in a calorie deficit are two different goals. Mayo supports the first one easily and can work against the second one if you stop measuring it.
How Much Mayo Can You Actually Eat on Keto?
There’s no official daily limit, and a condiment this low in carbs doesn’t need one. As a practical guide, most keto meal plans use mayo the way you’d use any high-fat condiment: a tablespoon or two per serving, a few times a day, folded into dressings, dips, or salads rather than eaten by the spoonful.
If you’re using mayo to hit a specific fat target for the day, or as a calorie-dense add-on when appetite is low, larger amounts are fine from a keto-macro standpoint. If weight loss through a calorie deficit is also a goal, track it like you would any other fat source, since its calories add up quickly compared to lower-fat condiments like mustard or hot sauce.
How to Choose (or Make) Keto-Friendly Mayo
Buying mayo: Look for full-fat, traditional mayonnaise with a short ingredient list: oil, eggs or egg yolks, vinegar or lemon juice, salt. Widely available options that typically fit this profile include Duke’s, Hellmann’s/Best Foods Real Mayonnaise, Kewpie, Primal Kitchen (avocado oil), and Sir Kensington’s (several oil options).
Ingredients change over time, so check the current label rather than relying on brand reputation alone. If you have an egg allergy, look for “vegan mayo,” which swaps egg yolk for a plant-based emulsifier like aquafaba or soy protein; carb counts are usually still low, but confirm on the label.
Making your own: Homemade mayo takes about five minutes and gives you full control over the oil.
- 1 large egg (use pasteurized eggs if you’re concerned about eating raw egg)
- 1 cup neutral oil (avocado oil or light, not extra-virgin, olive oil)
- 1 tablespoon lemon juice or vinegar
- 1/2 teaspoon salt, 1/2 teaspoon mustard (optional, helps it emulsify)
Combine everything except the oil in a tall, narrow container. Using an immersion blender, blend for a few seconds until combined, then slowly drizzle in the oil while blending continuously until it thickens into mayo, usually in under a minute. Store in the fridge and use within a week, since homemade mayo lacks the preservatives that give store-bought versions a longer shelf life.
Simple Ways to Use Mayo on Keto
- Salad binder: Tuna salad, egg salad, chicken salad, coleslaw
- Sauces: Garlic aioli, keto ranch, spicy mayo, remoulade
- Spread: On lettuce wraps or low-carb bread instead of higher-carb condiments like ketchup or barbecue sauce
- Dip base: Mixed with hot sauce, herbs, or spices for a quick vegetable or pork rind dip
- Baking: Some keto baking recipes use mayo to add fat and moisture to breads and muffins without adding carbs
Frequently Asked Questions
Mayo doesn’t cause weight loss or gain on its own. It supports ketosis because it’s virtually carb-free, but at roughly 95 calories per tablespoon, it can slow weight loss if you’re not tracking portions alongside other high-fat foods.
Standard, full-fat versions of both are keto-friendly, with under a gram of net carbs per tablespoon. Always check the current label, since ingredients and formulations can change by region and over time.
Usually not. Manufacturers replace fat with modified starch and sugar to maintain texture, which raises the carb count well above regular mayo. Stick to full-fat versions on keto.
Traditional mayo has little to no added sugar, though trace amounts sometimes appear from vinegar or flavorings. Light and flavored mayos are far more likely to contain meaningful added sugar.
Yes, moderate daily use is common on keto and doesn’t threaten ketosis given how low it is in carbs. Keep an eye on total calories if weight loss is also a goal, since mayo is calorie-dense.
The Bottom Line
Mayonnaise is one of the more forgiving foods on keto: nearly zero carbs, high in fat, and genuinely useful in the kitchen. The main risks are grabbing a “light” jar out of habit or losing track of how much you’re using. Check the label, favor full-fat, and mayo can stay a permanent fixture on your keto grocery list.
DT Nimra Naqvi is an MPhil-qualified clinical nutritionist specialising in therapeutic, condition-specific nutrition care. She designs personalised nutrition plans for metabolic, hormonal, digestive, and recovery-related conditions, grounded in evidence-based practice. Her work focuses on integrating nutrition with medical treatment and rehabilitation to support sustainable health outcomes. DT Nimra Naqvi provides professional online consultations for international clients across the USA, UK, and Europe.
