Another way to gauge fiber: Look at the fiber number. Yes, it sounds obvious, but many people, like me, don't know what the amounts mean. The recommended DV is 25 grams a day for a 2,000-calorie diet. “But the average person gets half that amount,” says Moores. “Most adults should aim for 30 grams.” A food with 2.5 grams or more of fiber per serving is considered a good source, according to Moores. A food with 5 grams or more per serving, such as beans or whole-grain products with added bran, is excellent.