Chia Seeds

Chia seeds deliver the highest fiber density per serving of any food on this list: 9.75 grams of fiber in a single 28-gram ounce, with a roughly equal split between soluble and insoluble fiber. The soluble fraction gels in liquid, absorbing 10 to 12 times its weight in water, slowing gastric emptying and feeding Bifidobacterium and Lactobacillus strains linked to gut barrier health. Each tablespoon also provides 1.8 grams of omega-3 ALA and 30 milligrams of lignans. Cost runs $0.20 to $0.35 per ounce, and shelf life reaches 2 to 4 years. Hydrate chia before eating to avoid esophageal gel bolus.