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Fiber intake calculator
Find your daily fiber target from the US adequate intake: 14 grams for every 1,000 calories you eat, or the reference value for your age and sex.
Log meals, water and side effects in GLPMate and see how they line up over the week.
The US Dietary Reference Intakes set fiber at 14 g per 1,000 kcal, which works out to about 38 g a day for men and 25 g for women aged 19–50, and 30 g and 21 g from age 51. On a GLP-1, constipation is a common side effect: raise fiber gradually and drink more fluid as you do.
How the target is set
The adequate intake for fiber comes from the US National Academies' Dietary Reference Intakes. It is based on the intake linked with a lower risk of heart disease in large studies — 14 g per 1,000 kcal — applied to typical calorie intakes for each age and sex.
| Age | Women | Men |
|---|---|---|
| 19–50 | 25 g | 38 g |
| 51 and over | 21 g | 30 g |
Eating less on a GLP-1
If you eat fewer calories, 14 g per 1,000 kcal gives a lower number than the age-and-sex value; enter your usual calories to see it. Either way, fiber-rich foods — vegetables, fruit, legumes, whole grains, nuts and seeds — also bring vitamins and minerals that matter more when portions shrink.
Increase slowly
A sudden jump in fiber can cause bloating and gas, especially when digestion is already slower. Build up over a few weeks, spread fiber across your meals and drink enough fluid.
This calculator is for general education only. It is not medical or dietary advice. If you have a bowel condition, have had bowel surgery or take medicines affected by fiber, ask your clinician before changing your fiber intake.
Sources
- US National Academies — Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005) — adequate intake of 14 g per 1,000 kcal: 38 g / 30 g for men and 25 g / 21 g for women (ages 19–50 / 51+)
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Fiber questions
How much fiber should I eat a day?
The US adequate intake is 14 g per 1,000 kcal — about 25 g a day for women and 38 g for men aged 19–50, and 21 g and 30 g from age 51. Most adults eat well below this.
Can fiber help with constipation on a GLP-1?
It can, together with enough fluid and regular movement. Raise fiber gradually, because adding a lot at once can make bloating worse. If constipation lasts several days, is severe, or comes with pain or vomiting, contact your prescriber.
Should I take a fiber supplement?
Food first is the usual advice, because fiber-rich foods also supply other nutrients. Some people use a supplement such as psyllium; check with your clinician or pharmacist first, as some supplements can change how certain medicines are absorbed.
Why does the calculator ask for calories?
Because the reference is set per 1,000 kcal. If you eat noticeably less than usual — common on a GLP-1 — your calorie-based number will be lower than the standard value for your age and sex.
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