What you need to do
Get to 25 grams of fiber a day for a week. Closing the gap usually takes one swap and one addition: beans in something, and a fruit or vegetable you were not going to eat.
Options that work
- A cup of black beans or lentils: 15 g
- A cup of raspberries: 8 g. A pear with the skin: 5 g
- Oatmeal (1 cup cooked): 4 g. Add chia (1 tbsp): 5 g more
- An avocado: 10 g
- Two slices of true whole-grain bread: 6 g
- Psyllium, about 10 g in water, on the days you fall short. It is the one fiber supplement with real evidence
Tip for success
Go up over a few days, not overnight, and drink more water as you go. Fiber without water is how people decide fiber is not for them.
Part of the fundamental Half the plate plants.
Why this works
American adults average about 15 grams of fiber a day against a target of 25 to 38 [59]. More whole grains meant lower heart disease and lower death from any cause across 45 cohorts [58]. Psyllium, about 10 grams a day, lowered LDL cholesterol across 28 trials and helps the constipation that comes with GLP-1 medicines [89]. Fiber plus water plus a daily walk is the standard advice for digestion on those drugs [25].
Sources
- USDA fiber intake data. American adults average about 15 g of fiber a day against a target of 25 to 38 g. Almost everyone is short.
- Aune 2016, BMJ. Across 45 cohorts, more whole grains meant lower heart disease and lower death from any cause, up to about 90 g a day.
- Jovanovski 2018, Am J Clin Nutr. About 10 g of psyllium a day lowered LDL cholesterol across 28 trials. It also helps the constipation that comes with GLP-1 medicines.
- Mozaffarian 2025, joint advisory, Obesity. Four societies' advice for people on GLP-1 medicines: protein 1.2 to 1.6 g/kg a day spread across meals, resistance training, small low-fat meals during dose increases, fluids, fiber, and a plan for low-appetite days. Protein without lifting is called 'likely inadequate'.
The fridge version
One line, seven boxes. Print it and put it where you eat.
Fiber up · one week
25 grams of fiber a day, seven days. Most people are at 15.
Tip: Go up over a few days, not overnight, and drink more water as you go. Fiber without water is how people decide fiber is not for them.