Yogurt is cultured milk, much like butter-milk, sour cream, and crème fraîche, and develops from the action of acid-producing bacteria. Yogurt bacteria eat the milk sugar called lactose, which makes yogurt a wonderful milk substitute for those who are lactose intolerant.
Until the early ‘50s, yogurt couldn’t be found in the United States except in ethnic markets. Today Americans eat more than one billion cups a year. We seem to have finally acquired a taste for it. Now you can buy yogurt plain (about 150 calories per cup); flavored, usually with lemon, vanilla, or coffee (200 to 250 calories per cup); with fruit on the bottom (raspberry has 225 to 300 calories per cup); Western style—flavored and with fruit on the bottom; or Swiss or French style, with fruit blended throughout. Calories and nutrients differ from brand to brand, but if you want yogurt without the fat (whole milk yogurt has about 3.5 percent fat) you can opt for low-fat yogurt (with 1 to 2 percent fat) or skim milk yogurt (with .5 percent fat).