What is the difference between Greek yogurt and regular yogurt?
Both Greek and regular yogurt start as milk fermented with live bacterial cultures, but Greek yogurt gets an extra straining step that drains off much of the liquid whey. That makes Greek yogurt thicker, creamier, and tangier, and it concentrates protein—Harvard Health notes a typical serving has roughly double the protein of regular yogurt—while also cutting carbohydrates and lactose by about half. Regular yogurt stays looser and milder and usually keeps more calcium because less whey (and the minerals in it) is removed. Both can supply probiotics; choose plain or low-sugar versions and compare labels, since flavored cups vary widely.
Source: Harvard Health — Greek yogurt