So you eat half a kilo of raspberries, and then the rest of your diet is a juice cleanse? Here an example diet: oats for breakfast (6 g), a sandwich loaded with greens for lunch (4 g), chili for dinner (15 g). Throw in an apple for a snack (5 g). It's really not that hard.

The National Academy of Medicine recommends:

• Women 51 and older: 21 grams of fiber per day
• Men 51 and older: 30 grams of fiber per day

Now your numbers go with 45 g per day, but honestly that example diet would leave me hungry. I'd probably also have a peanut butter and banana sandwich (7 g). Throw in a small amount of berries or raisins into the breakfast oats and we've hit your higher target.