Sour cream is lower in calories, sodium, and total fat than mayonnaise, making it the lighter choice in most side-by-side comparisons. But “healthier” depends on what you’re optimizing for. Mayo delivers more heart-friendly unsaturated fats, while sour cream brings calcium and potentially beneficial bacteria. The better pick comes down to how you use each one and what your body needs.
Calories and Fat Per Tablespoon
A tablespoon of regular mayonnaise contains roughly 94 calories and 10 grams of fat. A tablespoon of full-fat sour cream has about 23 calories and 2.4 grams of fat. That’s a massive gap, and it’s the main reason people reach for sour cream when they want to cut calories. Even if you use two tablespoons of sour cream to replace one of mayo, you’re still coming out ahead on calories.
The type of fat matters, though. Mayo is mostly unsaturated fat from plant oils like soybean, sunflower, or canola. Two tablespoons contain around 4 grams of saturated fat, with the rest being mono- and polyunsaturated. Sour cream’s fat is almost entirely from dairy, so a higher percentage is saturated. Two tablespoons deliver about 3.5 grams of saturated fat, which is close to mayo’s number despite having far less total fat. Gram for gram, sour cream carries a heavier saturated fat load.
Sodium Levels Are Not Even Close
This is where sour cream pulls far ahead. A tablespoon of regular mayonnaise contains 78 to 96 milligrams of sodium, depending on the brand. Fat-free versions can climb to 120 milligrams per tablespoon. A tablespoon of full-fat cultured sour cream? Just 4 milligrams. Reduced-fat sour cream is still only about 13 milligrams.
If you’re watching your salt intake for blood pressure or heart health, swapping mayo for sour cream in recipes like potato salad, coleslaw, or sandwich spreads can meaningfully reduce your sodium for the day.
The Omega-6 Problem With Mayo
Most commercial mayonnaise is made with soybean oil, which is high in omega-6 fatty acids and low in omega-3s. Lab analyses of standard soybean-oil mayo show an omega-3 to omega-6 ratio of roughly 0.13 to 1, meaning you’re getting about 8 times more omega-6 than omega-3. Western diets already tilt heavily toward omega-6, and excess omega-6 intake is linked to increased inflammation over time.
Sour cream contains very little polyunsaturated fat of either type, so it doesn’t contribute meaningfully to this imbalance. If you already eat a lot of processed foods made with vegetable oils, replacing some mayo with sour cream reduces your overall omega-6 intake. Mayo brands made with avocado oil or olive oil offer a better fatty acid profile, but they cost more and aren’t what most people have in the fridge.
Nutrients Sour Cream Adds
Because sour cream is a dairy product, it provides calcium, phosphorus, vitamin A, and small amounts of vitamin B12. A two-tablespoon serving won’t cover a significant share of your daily needs, but these nutrients are essentially absent from mayo. If you’re using sour cream regularly as a topping or base for dressings, those small contributions add up over a week.
Sour cream also contains live bacterial cultures in most cases. In the U.S., products labeled “cultured sour cream” are typically not heat-treated after fermentation, so active bacteria remain in the container. Products labeled “acidified sour cream” were made without bacterial cultures and won’t offer the same benefit. The probiotic effect of sour cream is modest compared to yogurt or kefir, but it’s a bonus mayo can’t match. Check the label for “live active cultures” if this matters to you.
Where Mayo Wins
Mayo isn’t without its strengths. Its unsaturated fat content helps your body absorb fat-soluble vitamins (A, D, E, and K) from vegetables. Adding mayo to a salad or sandwich with leafy greens or tomatoes can increase how much of those nutrients you actually take in. The egg yolk in traditional mayo also provides choline, a nutrient involved in brain function and liver health that many people don’t get enough of.
Neither condiment raises blood sugar in any meaningful way. Both are classified as fat sources with little to no effect on blood glucose, so for people managing diabetes or insulin resistance, neither is a concern on its own.
Practical Swaps That Work
Sour cream substitutes well for mayo in cold dishes: baked potatoes, tacos, dips, creamy dressings, and cold salads. It doesn’t work as a direct swap in recipes where mayo provides structure, like binding a tuna or chicken salad. In those cases, you can often use a 50/50 blend of sour cream and mayo to cut calories and sodium without losing the texture you need.
If you want to go a step further, plain low-fat Greek yogurt outperforms both. It has 73 calories per 100 grams compared to 135 for low-fat sour cream, and it delivers about 10 grams of protein per 100 grams versus sour cream’s 2.9 grams. Greek yogurt works as a stand-in for sour cream in nearly every application and adds meaningful protein to meals. The tang is slightly sharper, but most people adjust quickly.
Which Should You Choose
For everyday use as a topping, dip base, or dressing ingredient, sour cream is the lighter, lower-sodium option with a small edge from calcium and live cultures. If you’re making a recipe that specifically calls for mayo’s emulsified texture, use mayo, but consider olive-oil or avocado-oil versions to improve the fat profile. Blending the two is a simple compromise that works in most cold dishes.
The biggest factor is volume. People tend to use less sour cream per serving than mayo because it’s used as a topping rather than a binding ingredient. That natural portion control, combined with fewer calories per tablespoon, is the real reason sour cream tends to be the better day-to-day choice for most people.