With macronutrients like protein, carbs and fat hogging the spotlight, fiber doesn't quite get the hype it deserves. Indeed, many of today's trendy diets focus on filling up on fat — keto, we're looking at you — or protein, but fiber remains the unsung VIP when it comes to weight loss.
Case in point: Americans aren't getting nearly enough of this nutrient. According to a January 2017 study in the American Journal of Lifestyle Medicine, approximately 95 percent of us fall short of eating the recommended daily amount.
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FYI, the 2015-2020 Dietary Guidelines for Americans recommend women age 50 and younger eat at least 25 grams of fiber daily and men get 38 grams. For those over 50, women should aim for 21 grams and men should shoot for 30 grams each day.
How Fiber Can Help You Lose Weight
Research has shown that eating enough fiber can help improve heart health, digestion, blood sugar control and, yes, help you lose weight.
In fact, an October 2019 study in The Journal of Nutrition, which had 345 people follow a calorie-restricted diet rich in fiber (at least 20 grams daily) for six months, found that dietary fiber promotes weight loss and diet adherence in those who have overweight or obesity.
"Dietary fiber helps regulate hormones and delays gastric emptying, which is associated with increased feelings of satiety," Brigid Titgemeier, RDN, LD, a functional medicine registered dietitian and founder of My Food Is Health, tells LIVESTRONG.com.
Fiber also helps regulate blood sugar levels, which can lead to lower insulin sensitivity, Titgemeier says. "Because insulin is a fat-storing hormone, keeping blood sugar levels low is key for lowering your insulin response and, therefore, improving weight-loss outcomes."
With that said, it's not quite as simple as "eat more fiber, lose weight." Here are some of the most common mistakes to avoid when it comes to adding more fiber to your diet.
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3 Common Fiber Mistakes to Avoid
1. You Rely on 'Fake' Fiber
Because most Americans lack fiber in their diets, many food companies are sneaking the nutrient into packaged snacks like fiber bars, cereals, chips and even some fruit candy snacks. But the fiber in these foods isn't the type you'll get from eating vegetables, fruits and whole grains.
"Fibers that are synthetically added to packaged foods are called functional fibers," Titgemeier says. "Functional fibers are any fiber ingredient that is not derived from a whole food. These include beta glucans, inulin, chicory root and many more."
Titgemeier says these functional fibers haven't been shown to have any negative effects on your health, but they may cause gastrointestinal distress, especially for those with small intestinal bacterial overgrowth (SIBO) or dysbiosis.
They also don't necessarily provide the same benefits that the fiber from whole foods offers. For example, a February 2017 review in the Journal of the Academy of Nutrition and Dietetics found that functional fibers don't lower LDL (bad) cholesterol levels the same way soluble fiber from vegetables and fruits does.
"I recommend people strive to get most of their fiber from whole food, plant-based sources given that these foods are the most optimal foundation of a diet," Titgemeier says.
2. You Increase Your Fiber Too Quickly
Another common mistake people make with fiber is upping their intake dramatically, which can cause bloating, cramping, constipation, diarrhea and gas. To help prevent these uneasy symptoms, aim to gradually increase how much you eat, Titgemeier says.
"Rather than increasing your daily vegetable consumption from one cup to five cups overnight, try adding one additional cup of vegetables per week to allow your intestines to adjust," she recommends.
Also, try not to eat too many different types of nuts and seeds at once, or too many beans and lentils in one day. "Beans and lentils contain at least five grams of fiber per half cup. And while they can be a very nutritious staple, eating too many can create more gas, bloating and abdominal pain," Titgemeier explains.
As far as nuts and seeds go, Titgemeier says adding a tablespoon of chia seeds to your dishes, like in yogurt, smoothies and salads, can help counteract some of these GI symptoms.
3. You Don't Drink Enough Water
As you increase your fiber, it's important to also bump up your hydration levels to reap the full benefits.
Soluble fiber — found in beans, nuts, seeds and some fruits and vegetables — dissolves in water to create a gel-like substance, which helps you stay full for a longer period of time.
"Soluble fiber [is] similar to a sponge in your system. This sponge swells and helps to slow the passage of food from the stomach to the small intestine, making you feel more satiated and energized," Titgemeier says.
Insoluble fiber — found in whole grains and vegetables — adds bulk to your stool for healthy bowel movements, but it needs to collect water to do so.
Titgemeier recommends aiming to drink half your body weight in fluid ounces daily. For example, if you weigh 140 pounds, that would be 70 fluid ounces — or about 9 cups — of water per day.
Some quick tips from Titgemeier that can help keep your hydration levels up:
- Carry a large water bottle and know how many times you need to fill it up throughout the day to reach your hydration goal.
- Drink a glass of water first thing in the morning before you drink anything else.
- Make your H2O more flavorful with fresh fruit or fruit powders, like True Lemon packets.
- Purchase a SodaStream to make your own seltzer at home.
- Incorporate herbal teas, such as turmeric, hibiscus and cinnamon, to increase your antioxidant intake. "Herbal teas are caffeine-free and can be consumed in the afternoon with no concern of interfering with your sleep," Titgemeier says.
- American Journal of Lifestyle Medicine: "Closing America's Fiber Intake Gap"
- 2015-2020 U.S. Dietary Guidelines: "Appendix 7. Nutritional Goals for Age-Sex Groups Based on Dietary Reference Intakes and Dietary Guidelines Recommendations"
- The Journal of Nutrition: "Fiber Intake Predicts Weight Loss and Dietary Adherence in Adults Consuming Calorie-Restricted Diets: The POUNDS Lost (Preventing Overweight Using Novel Dietary Strategies) Study"
- U.S. National Library of Medicine: "Soluble vs. Insoluble Fiber"
- Journal of the Academy of Nutrition and Dietetics: "Understanding the Physics of Functional Fibers in the Gastrointestinal Tract: An Evidence-Based Approach to Resolving Enduring Misconceptions about Insoluble and Soluble Fiber"