--- title: "Fiber Intake Calculator — Daily Grams | GLPMate" url: https://glpmate.me/tools/fiber-intake-calculator language: en description: "How much fiber do you need a day? 14 g per 1,000 kcal or the adequate intake for your age and sex — and how to add fiber on a GLP-1 without more bloating." updated: 2026-10-14 --- Free tool · no signup # 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. **Spot what helps on hard days** Log meals, water and side effects in GLPMate and see how they line up over the week. [ Download on the **App Store** ](https://glpmate.go.link?adj_t=22klhq12&adj_campaign=tools-fiber-intake-calculator&adj_redirect_android=https%3A%2F%2Fapps.apple.com%2Fapp%2Fid6788548235&adj_redirect_macos=https%3A%2F%2Fapps.apple.com%2Fapp%2Fid6788548235&adj_redirect_windows=https%3A%2F%2Fapps.apple.com%2Fapp%2Fid6788548235) [ GET IT ON **Google Play** ](https://glpmate.go.link?adj_t=22klhq12&adj_campaign=tools-fiber-intake-calculator&adj_redirect_ios=https%3A%2F%2Fplay.google.com%2Fstore%2Fapps%2Fdetails%3Fid%3Dapp.eleutheromania.glpmate&adj_redirect_macos=https%3A%2F%2Fplay.google.com%2Fstore%2Fapps%2Fdetails%3Fid%3Dapp.eleutheromania.glpmate&adj_redirect_windows=https%3A%2F%2Fplay.google.com%2Fstore%2Fapps%2Fdetails%3Fid%3Dapp.eleutheromania.glpmate) Quick answer 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. **On a GLP-1:** slower digestion can make constipation more likely. Add fiber a little at a time over a few weeks, drink more fluid as you do, and tell your prescriber if constipation is severe or comes with stomach pain or vomiting. [Constipation on a GLP-1: what helps →](/blog/glp-1-constipation-relief-2026) ## 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. ## Keep going [ **Constipation on a GLP-1** What helps, and when to call your doctor. Read → ](/blog/glp-1-constipation-relief-2026)[ **Water intake calculator** Daily fluid needs, with exercise and heat. Open tool → ](/tools/water-intake-calculator)[ **TDEE calculator** Estimate your daily calories first. Open tool → ](/tools/tdee-calculator) 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 1. [US National Academies — Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005)](https://doi.org/10.17226/10490) — 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+) Last updated: 2026-10-14 FAQ ## 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. ## See meals and side effects side by side. Food, water and symptom tracking in GLPMate. iOS & Android. [ Download on the **App Store** ](https://glpmate.go.link?adj_t=22klhq12&adj_campaign=tools-fiber-intake-calculator&adj_redirect_android=https%3A%2F%2Fapps.apple.com%2Fapp%2Fid6788548235&adj_redirect_macos=https%3A%2F%2Fapps.apple.com%2Fapp%2Fid6788548235&adj_redirect_windows=https%3A%2F%2Fapps.apple.com%2Fapp%2Fid6788548235) [ GET IT ON **Google Play** ](https://glpmate.go.link?adj_t=22klhq12&adj_campaign=tools-fiber-intake-calculator&adj_redirect_ios=https%3A%2F%2Fplay.google.com%2Fstore%2Fapps%2Fdetails%3Fid%3Dapp.eleutheromania.glpmate&adj_redirect_macos=https%3A%2F%2Fplay.google.com%2Fstore%2Fapps%2Fdetails%3Fid%3Dapp.eleutheromania.glpmate&adj_redirect_windows=https%3A%2F%2Fplay.google.com%2Fstore%2Fapps%2Fdetails%3Fid%3Dapp.eleutheromania.glpmate)