- What is dietary fiber?
- Fiber and blood sugar, weight, and more
- Fiber recommendations and patterns
- Sources of dietary fiber
- Ways to boost dietary fiber - and your action plan
- Fiber supplements
Dietary Fiber: A Different Kind of Carbohydrate
Just like starch, dietary fiber is made up of glucose (sugar) units…
…But your body can’t digest (break down) dietary fiber!
Your body can break down fat, protein, and carbohydrates like sugars and starches. You can get energy (calories) from them. Your body isn’t good at breaking down dietary fiber. It doesn’t provide much fuel for you, even though its structure is similar to that of starch.
Types of Dietary Fiber
What is dietary fiber? - Types
| Soluble Fiber (The "Gel") |
Insoluble Fiber (The "Broom") |
What it does:
- Dissolves in water
- Can help lower glucose and cholesterol levels
Best Sources:
Oatmeal, chia seeds, nuts, beans, lentils, apples, and blueberries.
|
What it does:
- Promotes regularity and reduces constipation
Best Sources:
Whole wheat, quinoa, brown rice, legumes, leafy greens like kale, almonds, walnuts, seeds, and fruits with skins (pears/apples).
|
More Ways to Classify and Categorize Fiber
Fermentable non-fermentable cellulose hemicellulose lignins beta-glucans guar gum inulin oligofructose oligosaccharides fructooligosaccharides pectins resistant starch psyllium polydextrose polyols inulin oligosaccharides pectins resistant starch gums
Bottom line: Keep it simple: focus on fiber from a variety of sources
Health Benefits of Dietary Fiber
- Satiety - feel full longer - weight management
- Cholesterol - help lower “bad” LDL cholesterol - heart health
- Digestion - adds bulk - reduces constipation
- Blood sugar - more stable - improved energy and lower diabetes risk
- Improved brain metabolism - better cognition
- Lower triglycerides and blood pressure - heart health
- Fiber has a range of benefits
- Gut microbiome - more diverse healthy gut bacteria
Fiber Consumption Can Support Weight Management!
Fiber Intake Predicts Weight Loss and Dietary Adherence in Adults Consuming Calorie-Restricted Diets: The POUNDS Lost (Preventing Overweight Using Novel Dietary Strategies) Study
Study question: Do people who consume more dietary fiber lose more weight?
Study methods:
- Assign to calorie-restricted diets (deficit of 750 calories per day)
- Monitor what participants eat
- Check weight loss after 6 months
- Compare weight loss to fiber intake
The four diets were:
- Low-fat, average protein: 20% fat, 15% protein
- Low-fat, high-protein: 20% fat, 25% protein
- High-fat, average protein: 40% fat, 15% protein
- High-fat, high-protein: 40% fat, 25% protein
Participants were asked to have a 750 calorie/day deficit.
Study Results
There were 345 participants. 53.9% were female, and the average age was 53 years. Average weight loss after 6 months was 7.27 kg (16 lb).
Dietary fiber was the strongest predictor of weight loss regardless of macronutrients (which diet they followed).
Other predictors of weight loss were:
- Energy density
- Adherence
- Baseline weight
- Changes in fiber, PUFA, and MUFA from baseline
Recommendations for Dietary Fiber Consumption
The general recommendation for fiber consumption is 14 grams of fiber per 1,000 calories. That’s about 25-40 grams of fiber per day for most people. Americans get less than half of that, on average!
The Top Sources of Calories in the US Are Low in Fiber!
These foods make up about 50% of American calorie consumption.
- Cakes, cookies, quick bread, pastry, pie: 7.2%
- Yeast breads and rolls: 7.1%
- Soft drinks, soda (includes diet): 5.4%
- Beef: 4.7%
- Crackers, popcorn, pretzels, chips: 4.7%
- Cheese: 4.6%
- Milk: 4.6%
- Candy, sugars, and sugary foods: 4.5%
- Poultry: 4.3%
- Alcoholic beverages: 3.7%
The American Diabetes Association says to, “emphasize minimally processed, nutrient-dense, high-fiber sources of carbohydrates.” Whether on a low or high-carbohydrate diet, it’s a good idea to choose high-quality, high-fiber foods!
Food Sources of Dietary Fiber - Plant-Based Foods
Fiber is a carbohydrate in plants.
- Whole Grains
- Nuts and Seeds
- Fruit
- Vegetables
- Legumes
Vegetables
| Vegetables |
Fiber (grams) |
| 1 cup cooked Brussels sprouts |
5–6 |
| 1 cup carrots, green beans, bell pepper, cauliflower, greens, mushrooms, onions |
3–5 |
| 1 cup tomatoes, celery, cucumber, jicama |
2 |
| ½ cup of corn, peas, or sweet potato |
2 |
Fruit
| Fruit |
Fiber (grams) |
| 1 cup blackberries or raspberries |
7–9 |
| 1 apple, pear, orange, grapefruit |
3–5 |
| 1 cup strawberries or blueberries, ½ cup tangerine, 1 banana |
3 |
These are just examples - aim for a variety!
Food Sources of Fiber - Grain, Legumes, Nuts, and Seeds
Legumes, Nuts, Seeds
| Legumes, Nuts, Seeds |
Fiber (grams) |
| ½ cup cooked or canned beans or lentils |
7–9 |
| Lentil or split pea soup, 1 cup |
5–8 |
| 1 ounce of almonds, sunflower seeds, chia seeds, or peanuts |
3–5 |
Grains and Grain Products
| Grains and Grain Products |
Fiber (grams) |
| ½ cup bran cereal, small high-fiber wrap or tortilla |
10–15 |
| 3 cups popcorn |
5 |
| ½ cup cooked oatmeal, whole-wheat pasta, brown rice, quinoa, barley |
3 |
| 1 ounce oat cereal or whole-grain crackers |
3–4 |
| 1 1-oz slice whole-wheat bread |
2 |
Tip: Choose whole grains and plant-based proteins for more fiber.
Sample High-Fiber Day
| Meal Category |
Items |
| Breakfast |
Scrambled egg whites, Whole-wheat toast, 1 tbsp PB, ½ cup blueberries |
| Lunch |
High-fiber wrap, 2 oz chicken, ¼ avocado, sprouts/tomato, Baby carrots |
| Dinner |
5 oz chicken, ½ cup brown rice, ½ cup green peas, 1 cup steamed broccoli |
| Snacks |
1 cup Greek yogurt, 1 apple, 1 string cheese, 12 almonds, 1 banana |
Sample High-Fiber Day - Daily Totals
- 1,500 calories
- 30+ grams of fiber (goal: 23)
- 40% calories from carbohydrates
- 130 grams of protein
You can increase fiber within your typical meal patterns!
To Get More Fiber: Add High-Fiber Starches: Grains, Legumes, and Starchy Vegetables
Less-processed versions are usually higher in fiber
- Use whole-grain versions of grain products like bread, pasta, cereal, rice, and crackers
- Eat popcorn instead of chips or pretzels
- Instead of fried/mashed potatoes, try baked potatoes or sweet potatoes, or corn or peas
- Choose bean, split pea, or lentil soup
- Include beans or lentils instead of meat
To Get More Fiber: Add Vegetables
- Add a vegetable side
- Green or chopped side salad
- Cooked vegetables
- Cut rice, pasta, or potato portions in half
- Mashed cauliflower or turnip, or veggie noodles
- Add vegetable toppings
- Vegetables on pizza
- Lettuce, tomato, peppers, cucumber on sandwiches
- Blend in vegetables
- Pasta sauce and meatloaf
- Vegetable in main course
- Switch to a salad
- Fajitas, stir fry, casserole
Non-starchy vegetables are low-calorie: enjoy!
To Get More Fiber: Add Fruit
- Try a variety of fruit when you can
- Switch from juice to whole fruit
- Swap half your dessert or a sweet snack for a piece of fruit
- Have fruit and protein for a snack
- Sweeten cereal, yogurt, and oatmeal with fruit instead of sugar
Get More Fiber at Breakfast
| Original Breakfast |
High-Fiber Breakfast |
| Cornflakes with milk |
Shredded wheat or Oat O’s, milk, ½ cup frozen raspberries |
| 2 grams of fiber |
8 grams of fiber |
Get More Dietary Fiber at Lunch
| Original Lunch |
High-Fiber Lunch |
| Turkey sandwich, chips |
Whole-grain bread, ½ ounce almonds, baby carrots, apple |
| 3 grams of fiber |
12 grams of fiber |
Get More Dietary Fiber at Dinner
| Original Lunch |
High-Fiber Lunch |
| Turkey sandwich, chips |
Whole-grain bread, ½ ounce almonds, baby carrots, apple |
| 3 grams of fiber |
12 grams of fiber |
What About Fiber Supplements?
Common Reasons People Use Fiber Supplements
- Can help increase fiber intake
- Have many of the benefits of fiber - like lowering blood sugar, supporting digestive regularity
- Likely safe if taken long-term
Cautions When Considering Fiber Supplements
- Fiber supplements aren’t a substitute for a nutritious diet
- Ask your healthcare provider about dose, type, and safety
- Fiber can lower blood sugar
- Start low and increase gradually to reduce gastrointestinal discomfort
- Drink lots of water to prevent choking
Over 10,000 phytonutrients have been found in foods - and aren’t in fiber supplements
After this webinar…
- Think of one high-fiber food you can add to each of your typical meals
- Check your kitchen for high-fiber foods
- Choose higher-fiber versions when you shop
References
Harvard School of Public Health
https://nutritionsource.hsph.harvard.edu/carbohydrates/fiber/
https://www.awissd.org/wp-content/uploads/2023/12/fiber_info.pdf
Nutrition Clinique et Métabolisme
Volume 39, Issue 3, September 2025, Pages 164-179
Alahmari LA (2024) Front. Nutr. 11:1510564
Miketinas et at J Nutr. 2019 Oct 1;149(10):1742-1748
https://www.ars.usda.gov/ARSUserFiles/80400530/pdf/DBrief/12_fiber_intake_0910.pdf
