Chia and flax are the two seeds most often reached for when fibre or plant omega-3s are the goal — but they behave differently in the kitchen, and the numbers explain why.
| Nutrient | Chia Seeds | Flaxseed |
|---|---|---|
| Calories | 517 kcal | 545 kcal |
| Protein | 17 g | 18 g ✓ |
| Total Carbohydrate | 38.3 g | 34.4 g |
| Dietary Fiber | 34.4 g ✓ | 23.1 g |
| Total Sugars | 0 g ✓ | 1.6 g |
| Total Fat | 32.9 g | 37.3 g |
| Saturated Fat | 3.33 g | 3.28 g ✓ |
| Sodium | 0 mg ✓ | 36.7 mg |
Notable compounds in each
When to choose each
Both are nutritional powerhouses in small servings, but chia seeds pull ahead on fibre — over 10g more per 100g than flaxseed — plus effectively zero sodium and virtually no sugar. Flaxseed counters with a touch more protein and a higher potassium content. Chia’s gel-forming fibre suits puddings and overnight oats; flaxseed is best bought pre-ground or ground fresh, since whole seeds tend to pass through largely undigested, then stirred into porridge or baking.
Common questions
Should I grind flaxseed before eating it? Yes — whole flaxseed has a hard outer coat that often passes through the digestive system undigested, so grinding it (or buying it pre-ground) is the reliable way to access its fibre and nutrients. Chia seeds don’t have this issue and can be eaten whole.
Which has more fibre, chia or flax? Chia seeds, by a clear margin — around 34g per 100g versus roughly 23g for flaxseed, making chia one of the most fibre-dense foods in this encyclopedia.
Nutrition values are USDA FoodData Central approximations — see our editorial approach for how we source and verify data.