Whatever fiber figure you are aiming for, thirty grams a day or another, eating half what you used to means fitting it into fewer bites. The foods that carry the most fiber in each serving count for more than they did, and the percentage beside the fiber line on a food box shows you which they are.
The number behind the fiber percentage on a box
Every percentage beside the fiber line on a Nutrition Facts label is a share of one number, 28 grams, the Daily Value for dietary fiber. A serving marked 10% therefore holds about 2.8 grams, a tenth of 28, and after it about 25 more grams have to come from other foods to reach 28 that day. On half the food there are fewer servings to share that out, so each one has to carry a larger part of it.
That 28 grams is a lower limit: eat at least this amount of dietary fiber on most days. The Daily Values assume a 2,000-calorie day, and your own calorie needs may be higher or lower, depending on your age, sex, height, weight and physical activity level. Americans generally do not get the recommended amount of fiber, and eating a diet high in it can increase the frequency of bowel movements, lower blood glucose and cholesterol levels, and reduce calorie intake.
As a general guide, a serving with 5% of the Daily Value or less of a nutrient is considered low in it, and a serving with 20% or more is considered high, and foods higher in dietary fiber are among the ones to choose more often. Because the guide is per serving, the percentage matches what you eat only if your bowl holds the amount printed beside the serving size. Half that amount gives you half the fiber, the same as every other line on the panel (see Read a food label for half a serving, and compare two packages fairly).
Why the recommended amount of fiber comes out different each time you look it up
Each recommended amount you look up was set for a different group of people, or for a standard 2,000-calorie day. Thirty grams sits within the span these amounts cover and matches none of them exactly:
| Amount | Who it is set for |
|---|---|
| At least 28 grams, on most days | Anyone reading a Nutrition Facts label, within a 2,000-calorie daily diet |
| 21 to 38 grams a day | Older children, adolescents and adults |
| 25 grams a day for women, 38 for men | Adults 19 to 50 years old |
| 22 to 34 grams a day, depending on age and sex | Adults |
The 25 and 38 grams apply to adults 19 to 50 only; if you are older than 50, the rows that include you are the label's 28 grams, the 21 to 38 grams and the 22 to 34 grams. On average, Americans now eat about 16 grams of fiber per day, five grams under the lowest amount in the table.
None of these amounts is given for someone eating less than they used to. Older adults sometimes do not get enough fiber because they may lose interest in food, and eating less for any reason means fewer servings for fiber to come from. For an amount fitted to what you eat now, ask a dietitian or another health care professional to plan meals with the right amount of fiber for you, and give them a rough idea of how much you eat in a day.
Where can fiber come from when there is less food going in?
When the plate is smaller, fiber has to come from foods that hold more of it in each serving, such as whole grain products, which have more fiber than refined grains. Choosing whole-wheat bread in place of white bread, or brown rice in place of white rice, raises the fiber in a meal you were going to eat anyway without making the meal bigger. Read food labels carefully to see how much fiber each choice has.
Foods high in fiber include:
- vegetables, such as spinach, raw carrots, broccoli, artichokes, squashes and string beans; tender cooked vegetables such as asparagus, beets and pumpkin; and baked potatoes and sweet potatoes with the skin on
- legumes, such as lentils, black beans, split peas, kidney beans, lima beans and chickpeas
- nuts and seeds, such as sunflower seeds, almonds, pistachios and pecans
- fruits, such as apples, bananas, peaches, pears, berries, prunes, kiwis, and figs and other dried fruits
- grains, such as oatmeal, whole-grain breads, brown rice, quinoa, popcorn, whole-wheat pasta, and high-fiber cereals such as bran and shredded wheat
Taking the peels off fruits and vegetables reduces the amount of fiber you get from the food, so leave the skin on where you would eat it. Fiber-rich foods offer health benefits eaten raw or cooked, which helps if soft cooked vegetables are easier to manage on a small appetite.
Fiber comes in two forms, and most high-fiber foods contain both, some with more of one than the other. Soluble fiber attracts water and turns to gel during digestion, which slows digestion, and is found in oat bran, barley, nuts, seeds, beans, lentils, peas and some fruits and vegetables. Insoluble fiber adds bulk to the stool and helps move food more quickly through the stomach and intestines, and is found in foods such as wheat bran, vegetables and whole grains. A mix of vegetables, fruits, whole grains, and legumes and beans gets you some of each.
If your diet is balanced, you likely do not need a fiber supplement. Fiber supplements and foods artificially fortified with fiber often do not deliver the same health benefits as foods naturally high in fiber, and they may worsen bloating and gas. If your doctor has already told you to take one, ask them before you change it.
What happens if you add fiber fast to close the gap
A large amount of fiber added in a short time can cause intestinal gas, bloating and abdominal cramps, and that discomfort often goes away once the natural bacteria in your digestive system get used to the increase. Adding fiber slowly over a few weeks, instead of all at one time, can help reduce gas or diarrhea and avoid stomach distress. One change at a time, such as a single whole-grain swap before the next, keeps to that pace.
If you get bloating or gas while you are adding fiber, you have probably eaten too much fiber and need to reduce the amount you eat for a few days, then increase it again more slowly. Drink plenty of fluids as you go: when you increase fiber in your diet, you also need to get enough fluids, and not getting enough may make constipation worse. Water helps fiber pass through the digestive system, and about 8 glasses of water or noncaloric fluid a day is the general figure. If a doctor has told you to limit fluids, ask that doctor before you drink more; otherwise, your health care provider or a dietitian can tell you how much fluid you should be getting each day.
Too much fiber may interfere with the absorption of minerals such as iron, zinc, magnesium and calcium. In most cases this is not a cause for too much concern, because high-fiber foods tend to be rich in minerals themselves.
If fewer bowel movements or hard stools sent you looking at fiber, those have their own self-care steps and their own signs for seeing a doctor (see Two bowel movements a week: constipation, or just eating less?).
If NicoCares coordinates your care, tell your care team how much less you are eating than before, and whether a dietitian has already given you a fiber or fluid figure. Put both in a Spruce message; Spruce is the secure app where your NicoCares care team replies.
