What it means
Fiber comes from vegetables, fruit, beans, lentils, whole grains, nuts and seeds. There are two broad types. Soluble fiber forms a gel and slows digestion. Insoluble fiber adds bulk and helps food move through the gut.
MedlinePlus says older children, teens and adults should aim for about 21 to 38 grams a day, depending on age and sex, while Americans average closer to 16 grams. A common rule from the Dietary Guidelines is about 14 grams per 1,000 calories eaten.
Add fiber slowly over a few weeks and drink enough fluid, since a sudden jump can cause gas and bloating. That advice matters more on a GLP-1, when stomach emptying is slower and portions are smaller.
When appetite is low, fiber-rich foods that also carry protein, such as beans, lentils and edamame, help cover two needs at once.
Why it matters
Enough fiber helps prevent the constipation many people get on GLP-1 medicines.