6 Fiber Sources. Mixes Easily. The True Strength of Fiber: It's generally recommended that adults consume 25 to 35 grams of fiber per day. Most Amercians only get about half of that amount. Fiber's value to athletes and health-conscious individuals is centered on its important role in digestive system support. If you're not consuming enough fruits and vegetables to meet your fiber needs, adding a teaspoon of Fitness Fiber to your favorite beverage, protein shake, oatmeal, or bowl of cereal gets you 5 grams closer to meeting your goal-with only 10 additional calories.