Greek yogurt and sour cream have similarities in both taste and texture. Greek yogurt has very little whey, the watery component that is present in most thinner yogurts, so it’s just as thick as sour cream. If you compare equal portions, they're both good sources of protein, calcium and vitamin B-12. However, a typical serving of sour cream has significantly fewer nutrients and more fat than a 1-cup serving of Greek Yogurt.
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Both Greek yogurt and sour cream come in full-fat and reduced-fat varieties. The full-fat versions are made with cream or whole milk, which has at least 3.25 percent milk fat. Lower-fat varieties have less fat and cholesterol per serving and as a consequence contain fewer total calories. Sour cream does not come flavored, but you'll find many varieties of Greek yogurt, with added fruit, vanilla and other flavors. These additional ingredients may add extra sugar and calories.
Calorie and Fat Comparison
The nutritional differences between fat-free and full-fat varieties of both Greek yogurt and sour cream can be dramatic. While nonfat Greek yogurt has just 133 calories per cup, 1 gram of fat and 8 grams of carbohydrates, a 1-cup serving of the full-fat type has 300 calories, 23 grams of fat and 7 grams of carbohydrates. One cup of sour cream has more calories and fat than Greek yogurt even when it's a low-fat brand. One cup of reduced fat sour cream has 416 calories, 32 grams of fat and 16 grams of carbohydrates. However, you're not likely to eat an entire cup of sour cream. For comparison, 2 tablespoons of reduced fat sour cream contain 43 calories, 3 grams of fat and 2 grams of carbs.
If you compare 1 cup of Greek yogurt to sour cream, you'll find they're both rich sources of protein, calcium and vitamin B-12. Greek yogurt is significantly higher than sour cream in both protein and vitamin B-12, with 1 cup providing 71 percent of your recommended daily allowance of B-12 and about half of your daily protein. They both provide one-fourth to one-third of the RDA of calcium. While 2 tablespoons of sour cream don't begin to compare to the nutrients in a 1-cup portion, this serving still provides about 3 percent of your daily calcium, vitamin B-12 and protein.
Both sour cream and Greek yogurt have positive nutritional properties, especially the fat-free varieties because they deliver lean protein. Eating low-fat protein can have a satiating effect, which may work to curb your total calorie consumption. An added bonus to Greek yogurt is that it contains probiotics, which are live bacteria that support the healthy bacteria in your gastrointestinal tract and may help treat some digestive disorders. To be sure you're getting probiotics, check the label on the yogurt you buy for live, active cultures. The pasteurization process kills bacteria from the fermentation process, so live cultures must be added back after processing.