Calories in Flaxseeds: Nutrition Facts & Serving Sizes
Per 1 cup, whole (168g)
Per 100g
Source: USDA FoodData Central, SR Legacy, March 2026.
Flaxseed is a small, nutrient-dense seed derived from the flax plant (Linum usitatissimum). One tablespoon of whole flaxseed (about 10g) contains 55 calories, 1.9g of protein, 4.3g of fat, and 2.8g of fiber. Per 100g, flaxseeds provide 534 calories, 18.3g of protein, 42.2g of fat, and an exceptional 27.3g of fiber. The fat profile is dominated by polyunsaturated fat (28.7g per 100g), primarily ALA omega-3 fatty acids, making flaxseed one of the best plant-based omega-3 sources. The fiber content, particularly the combination of soluble and insoluble fiber, supports digestion and gut health significantly. Flaxseeds are also high in magnesium (392mg per 100g), potassium (813mg), and thiamin (1.6mg). Ground flaxseed is more bioavailable than whole seeds since the hull is difficult to digest. Add a tablespoon to oatmeal, shakes, or yogurt to boost omega-3 and fiber intake.
Nutrition Highlights
Calories by Serving Size
| Serving | Cal | Protein | Carbs | Fat | Fiber |
|---|---|---|---|---|---|
| 1 tsp, ground (3g) | 13.4 | 0.5g | 0.7g | 1.1g | 0.7g |
| 1 tbsp, ground (7g) | 37.4 | 1.3g | 2g | 3g | 1.9g |
| 1 cup, whole (168g) | 897.1 | 30.7g | 48.6g | 70.9g | 45.9g |
| 1 tbsp, whole (10g) | 55 | 1.9g | 3g | 4.3g | 2.8g |
| 1 tsp, whole (3g) | 18.2 | 0.6g | 1g | 1.4g | 0.9g |
| 100g | 534 | 18.3g | 28.9g | 42.2g | 27.3g |
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Full Nutrition Facts (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Calories | 534 | 27% |
| Protein | 18.3g | 37% |
| Total Fat | 42.2g | 54% |
| Saturated Fat | 3.7g | 19% |
| Total Carbohydrates | 28.9g | 11% |
| Dietary Fiber | 27.3g | 98% |
| Sugars | 1.6g | 3% |
| Sodium | 30mg | 1% |
Vitamins & Minerals (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Saturated Fat | 3.7g | 1% |
| Calcium | 255mg | 20% |
| Iron | 5.7mg | 32% |
| Potassium | 813mg | 17% |
| Vitamin C | 0.6mg | 1% |
| Vitamin B6 | 0.5mg | 29% |
| Magnesium | 392mg | 93% |
| Phosphorus | 642mg | 51% |
| Zinc | 4.3mg | 39% |
| Selenium | 25.4mcg | 46% |
| Folate | 87mcg | 22% |
| Thiamin (B1) | 1.6mg | 133% |
| Riboflavin (B2) | 0.2mg | 15% |
| Niacin (B3) | 3.1mg | 19% |
% Daily Values based on a 2,000 calorie diet (FDA reference).
Health Benefits of Flaxseeds
Flaxseed is one of the most studied functional foods. Its omega-3 ALA content (approximately 22g per 100g) is higher than any commonly consumed plant food. While ALA conversion to EPA and DHA is limited, regular intake has been associated with reductions in inflammatory markers and improvements in cardiovascular risk factors including blood pressure and triglyceride levels.
The fiber content at 27.3g per 100g is exceptionally high. Just one tablespoon of ground flaxseed adds nearly 2g of fiber to a meal. Soluble fiber forms a gel in the digestive tract that slows glucose absorption and improves insulin sensitivity, while insoluble fiber supports regular bowel movements and gut motility.
Flaxseeds are the richest dietary source of lignans, a class of polyphenols with antioxidant properties. Research has linked lignan intake to reduced markers of oxidative stress and potential benefits for hormone balance.
Magnesium at 392mg per 100g is notable. A tablespoon provides about 40mg, contributing to the 310 to 420mg daily recommendation for adults. Magnesium supports over 300 enzymatic processes including protein synthesis, muscle function, and ATP production.
Potassium at 813mg per 100g and zinc at 4.3mg per 100g add to the nutritional profile. Regular flaxseed consumption is practical for athletes looking to increase micronutrient density without adding bulk to their diet.
Dietary Considerations
Flaxseed is vegan, vegetarian, gluten-free, and dairy-free. It is paleo-compatible and Whole30-approved. For keto diets, the net carbs are low (28.9g total carbs minus 27.3g fiber equals roughly 1.6g net carbs per 100g), making ground flaxseed one of the most keto-friendly high-fiber foods available. For weight loss, the fiber and fat content makes flaxseed very satiating per calorie. At 534 calories per 100g, it is calorie-dense, so use measured tablespoon portions rather than free-pouring. Ground flaxseed is recommended over whole seeds for better nutrient absorption. Store ground flaxseed in the refrigerator to prevent the omega-3 fats from oxidizing.
Daily Intake (100g)
100g of flaxseed provides 27% of a 2,000-calorie diet.
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Frequently Asked Questions
How many calories in flaxseed?
One tablespoon of whole flaxseed (10g) contains about 55 calories. One tablespoon of ground flaxseed (7g) contains about 37 calories. Per 100g, flaxseed contains 534 calories.
Is flaxseed good for weight loss?
Flaxseed supports weight loss due to its high fiber content (27.3g per 100g) and satiating fat content. Studies show that soluble fiber from flaxseed reduces appetite and calorie intake over time. Use 1-2 tablespoons per day added to meals rather than large quantities given the calorie density.
How much protein in flaxseed?
Flaxseed contains 18.3g of protein per 100g. One tablespoon of ground flaxseed (7g) provides about 1.3g of protein. While not a primary protein source, flaxseed adds meaningful protein alongside its omega-3 and fiber benefits.
Should you eat whole or ground flaxseed?
Ground flaxseed is significantly better for nutrient absorption. Whole flaxseeds have a tough outer hull that often passes through the digestive system intact, meaning you absorb little of the omega-3s and other nutrients. Grind them yourself or buy pre-ground (milled) flaxseed.
How much flaxseed should I eat per day?
One to two tablespoons of ground flaxseed per day (7-14g) is a common recommended amount. This provides 1-2g of ALA omega-3s, 2-4g of fiber, and about 37-75 calories. Starting with one tablespoon and increasing gradually helps avoid digestive discomfort from the high fiber content.
Is flaxseed keto-friendly?
Yes. Ground flaxseed has approximately 1.6g of net carbs per 100g (28.9g total carbs minus 27.3g fiber). This makes it one of the most keto-compatible high-fiber foods. It is a popular addition to keto baking and smoothies.
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