Most protein bars deliver solid protein numbers but fall short on fiber. That matters because fiber slows digestion, stabilizes blood sugar, and keeps you feeling full longer. A bar with 20 grams of protein and 2 grams of fiber will leave you hungry far sooner than one with the same protein and 10 grams of fiber. For gut health, weight management, and sustained energy, fiber is the nutrient most protein bars quietly skip.
The average American gets about 15 grams of fiber per day, roughly half the recommended 25 to 30 grams. A high-fiber protein bar can close that gap meaningfully. We evaluated dozens of bars to find the ones that deliver both macros without compromising on taste or relying on questionable fiber sources.
For this list, we set a minimum of 8 grams of fiber per bar. That qualifies as a "good source of fiber" by FDA standards and puts these bars in a category above mainstream options that typically deliver 2 to 5 grams. We also considered the fiber source: soluble corn fiber and chicory root fiber (inulin) are the most common in protein bars. Bars using whole-food fiber sources like oats, nuts, and seeds scored higher in our evaluation.
Quest remains the gold standard for high-fiber protein bars. Most flavors deliver 14 to 17 grams of fiber alongside 20 to 21 grams of protein, with just 1 gram of sugar. The fiber comes primarily from soluble corn fiber, which is well-tolerated by most people. Chocolate Chip Cookie Dough and Cookies and Cream lead the flavor rankings. At roughly $2.50 per bar, the protein-to-fiber combo is hard to beat.
Fiber One builds its brand identity around fiber, and the protein bars deliver. Each bar provides 9 grams of fiber and 10 grams of protein at just 140 calories. The fiber blend includes chicory root extract, which can cause bloating in large amounts but is fine for most people at this dose. Caramel Nut and Oats and Chocolate are the most popular flavors. These are lighter bars, better as a snack than a meal replacement.
No Cow bars pack 16 to 18 grams of fiber per bar along with 20 to 22 grams of protein. They are dairy-free, plant-based, and use a blend of soluble corn fiber and brown rice protein. The fiber content is among the highest in the entire protein bar market. Chocolate Fudge Brownie and Peanut Butter Chocolate Chip are the best flavors. Texture is chewy and dense, which is not everyone's preference, but the macros are exceptional.
Built Bar delivers 15 to 17 grams of fiber in most flavors, paired with 17 grams of protein and only 130 to 150 calories. The fiber comes from soluble corn fiber. What sets Built apart is the texture: a light, truffle-like center coated in chocolate that does not feel like a traditional protein bar. Coconut, Salted Caramel, and Mint Brownie are standout flavors. The low calorie count makes these ideal for snacking without guilt.
SimplyProtein keeps it simple with 15 grams of protein, 8 to 10 grams of fiber, and a short ingredient list built around plant-based whole foods. The bars use chicory root fiber and are soy-free, gluten-free, and non-GMO. Peanut Butter Chocolate and Lemon Coconut are the cleanest-tasting options. At 150 calories per bar, they balance nutrition and clean ingredients better than most competitors.
RXBARs get their fiber from whole-food sources: dates, nuts, and egg whites. Most flavors deliver 5 to 7 grams of fiber, which falls below our 8-gram threshold but deserves mention because the fiber comes entirely from real food rather than added fiber extracts. The Peanut Butter and Chocolate Sea Salt flavors taste like elevated trail mix. If you prioritize whole-food fiber sources over raw fiber grams, RXBAR is the pick.
ONE bars deliver 8 to 10 grams of fiber per bar alongside 20 grams of protein and just 1 gram of sugar. Chicory root fiber is the primary fiber source. Birthday Cake and Maple Glazed Doughnut are the flavor highlights, tasting more like dessert than a health food. At 220 calories and a candy-bar texture, these balance indulgence and fiber content well.
Here is how the top bars stack up on fiber per serving:
If you want maximum fiber per bar, No Cow and Quest lead the pack with 14 to 18 grams. If you want whole-food fiber sources, RXBAR and SimplyProtein are the cleanest options. For the best balance of taste, fiber, and low calories, Built Bar is the standout. If you need both high fiber and high protein in a single bar, Quest is the most well-rounded choice at a reasonable price point.
One practical note: increasing fiber intake too quickly can cause bloating and digestive discomfort. If you are currently eating less than 15 grams of fiber daily, start with one high-fiber bar per day and give your gut a week to adjust before adding more. Drinking extra water with high-fiber bars also helps prevent digestive issues.
Yes. Soluble corn fiber is a prebiotic fiber recognized by the FDA as a dietary fiber. Studies show it supports digestive health and feeds beneficial gut bacteria, though it does not provide the same satiety as whole-food fiber sources like oats or vegetables.
They can, especially if you are not used to high fiber intake. Bars with chicory root fiber (inulin) tend to cause more gas than those using soluble corn fiber. Start slowly and drink plenty of water.
The USDA recommends 25 grams per day for women and 38 grams per day for men. Most Americans get about half that amount. A high-fiber protein bar can add 8 to 18 grams toward your daily target.
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