Fiber & Low Carb Diet

Low-carbohydrate dieters occasionally experience constipation due to low fiber intake. You can avoid gastrointestinal distress by making informed choices within the limits of most low-carb diets. Eating fruits and vegetables is essential to meeting your daily needs for fiber, antioxidants and other vital nutrients, according to low-carb advocate Dr. Leo Gallard, author of "The Fat Resistance Diet." Experts at MayoClinic.com agree that fiber intake can lower your risk of heart disease and diabetes, as well as prevent and relieve constipation.

How Low-Carb Diets Work

When digested by the human body, carbohydrates become glucose, which can spike blood-insulin levels. Low-carb proponents theorize that the lower levels of blood insulin enjoyed by low-carb dieters cause the body to burn fat instead of glucose. Lower insulin levels can also suppress appetite signals, making it easier for low-carb dieters to keep their caloric intake down. Other benefits of lower insulin levels include a reduced risk of heart disease and diabetes, according to Richard Feinman, professor of biochemistry at SUNY Downstate Medical Center.

Fiber Defined

Fiber, also called "bulk" or "roughage," is a carbohydrate that cannot be broken down during the digestion process. Other forms of carbohydrates are digested into glucose; fiber is not. When you look at a nutrition label made in the United States, fiber is a subcategory under carbohydrates. Low-carb dieters subtract the fiber grams from the carbohydrate grams to come to a "net carb" number. This is what is commonly used in programs that ask dieters to count the carbs they consume.

How Much Fiber

Adults should consume 21 g to 38 g of fiber per day, according to The National Academy of Sciences' Institute of Medicine. Whole foods, which also provide vitamins, minerals and other nutrients, are preferred sources, rather than supplements that provide fiber alone. Gallard's program lines up with these recommendations. He advises a minimum intake of 25 g of fiber coming from nine servings of vibrantly colored fruits and vegetables. A serving size for raw vegetables is about a cup; for cooked vegetables, about 1/2 cup; for fruits and root vegetables, a portion is about the size of a tennis ball.

Low-carb Fiber Sources

Low-carb enthusiasts often find that they are eating more than double the 12-g American average for fiber. Followers of the Fat Resistance Diet consume fiber as part of every meal and snack. Breakfast omelets highlight tomatoes, spinach or other vegetables. Lunch features leafy greens, broccoli florets, string beans, apples and oranges. Dinner options include grilled or roasted vegetables. Snacks and desserts are built around sweet berries.

Low-carb Nutrients

Much like other low-carb eating plans, Gallard's program offers a wealth of nutritional information about high-fiber fruit and vegetable choices. The human diet potentially includes some 400 different flavonoids, he says, yet most Americans consume only a tiny fraction of these powerful anti-inflammatory gems. Other nutrient categories highlighted in his program include anthocyanins from berries, carotenoids found in carrots and spinach and lycopene found in tomatoes.