try this for one day:
Breakfast to include at least a cup of fresh berries - rasberries are super stars in fiber.
Lunch to include a large (at least 5 cups greens) salad - spinach is great.
Dinner to include a couple of cups of some type of green vegetable - e.g. 2 cups broccoli.
AND at least 1/2 cup beans.
(Total of the above is 275 calories; fiber 25.8)