It's been scientifically proven that calcium can help prevent the risk of obesity. Half a liter of buttermilk already contains 75 percent of the recommended daily calcium requirement. It also happens to be very low in fat, making it a diet-friendly dairy option to keep you on track. To make homemade buttermilk, simply combine 1 cup milk with 1 tablespoon lemon juice or vinegar. Let stand for 5 to 10 minutes. Serve.