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Nuts and seeds

Hazelnuts

Hazelnuts packs 628 kcal into 100 g (3.5 oz), so a typical 25 g (0.9 oz) serving already adds up to about 157 kcal.

USDA description: Hazelnuts

  • High in fiber
  • Nutritious in small servings
  • High energy density

Estimated satietyHow it is calculated

Starting point+1
Very high energy density: 628 kcal/100 g−2
Protein: 2.4 g/100 kcal0
Fiber: 1.5 g/100 kcal0
Solid food with 5.3 g of water, under 700
Sum−1
Raised to the minimum of 11

Our own estimate from the values per 100 g: useful for comparing foods with each other, not a measurement in people. Holt index (1995): this food was not measured.

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Sources
9 primary
Data
USDA FDC 170581

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Nutrition facts

Calories
157 kcal per serving
628 kcal per 100 g (3.5 oz)
Protein
3.8 g per serving
15 g per 100 g (3.5 oz)
Carbohydrates
4.2 g per serving
16.7 g per 100 g (3.5 oz)
of which sugars
1.1 g per serving
4.3 g per 100 g (3.5 oz)
Fiber
2.4 g per serving
9.7 g per 100 g (3.5 oz)
Fat
15.2 g per serving
60.8 g per 100 g (3.5 oz)
of which saturated
1.1 g per serving
4.5 g per 100 g (3.5 oz)
Water
1.3 g per serving
5.3 g per 100 g (3.5 oz)

Source: USDA FoodData Central: Nuts, hazelnuts or filberts (FDC ID 170581), accessed September 23, 2026.

A typical 25 g (0.9 oz) serving provides about 157 kcal, 3.8 g of protein, and 2.4 g of fiber.

The typical serving (25 g (0.9 oz)) is a common amount used for the math, not a recommendation. Ounces and cups are rounded US equivalents; the values come from the database entry cited in the sources.

What it is and how to eat it

The Dictionary of the Spanish Language defines avellana (hazelnut) as the fruit of the hazel tree, almost spherical, about two centimeters across, with a hard, thin, cinnamon-colored shell and, inside, white, oily flesh covered by a reddish skin. This page covers unroasted hazelnuts according to USDA, with 628 kcal, 60.8 g of fat, 9.7 g of fiber and 15 g of protein per 100 g.

A 30 g (1.1 oz) serving, about 22 hazelnuts based on USDA's average weight, provides 188 kcal, 18.2 g of fat, 4.5 g of protein and 2.9 g of fiber, and only 10% of its energy comes from protein (my calculations), so it does not replace the protein part of the plate. A handful usually weighs more: in a study with 120 adults and six types of nuts, the median handful weighed 36.3 g, against 28.7 g when they were asked to serve 30 g (International Journal of Environmental Research and Public Health, 2021). The 2025 nutrition advisory on GLP-1 therapy suggests avoiding fatty or high-fiber foods in the first days of treatment and notes that foods high in protein or fat can further slow gastric emptying, so in those days, and after a dose increase, four or five chopped hazelnuts over yogurt may sit better than a handful.

What the evidence says

With USDA's figures, 92% of their fatty acids are unsaturated, mostly monounsaturated, and they provide 77% of their energy (my calculation), so they meet the "high unsaturated fat" condition the EU requires for the claim "replacing saturated fats with unsaturated fats in the diet contributes to the maintenance of normal blood cholesterol levels". Their 15 mg of vitamin E per 100 g exceed the minimum for a "high vitamin E" claim, and 30 g provides 4.5 mg, 38% of the reference value, so they could carry the authorized claim "vitamin E contributes to the protection of cells from oxidative stress" (Regulations (EC) No 1924/2006, (EU) No 1169/2011 and (EU) No 432/2012). By contrast, the EU register lists as non-authorized the claim that eating 30 g of nuts a day, hazelnuts included, as part of an energy restricted diet helps maintain a healthy weight, and another about hazelnut oil and the skin. Hazelnuts are among the tree nuts that labels must highlight as allergens in the EU (Regulation (EU) No 1169/2011), and in a European review published in 2024 in Allergy, the journal of the European Academy of Allergy and Clinical Immunology (EAACI), hazelnut allergy confirmed by a food challenge affected 0.04% of the population, although 4% said they had it.

The sources for this section are listed under "Sources" at the end of the page.

Satiety

The 1 to 5 score is our own estimate: it starts at 1 point, adds points for low energy density, for protein and fiber per 100 kcal, and for the water in solid foods, and subtracts points for drinks with calories. It is useful for comparing foods with each other; it is not a measurement in people.

What to keep in mind on a GLP-1 medication

High in fiber
It has at least 3 g of fiber per 100 g. Fiber adds bulk and slows digestion, which contributes to fullness, and it helps keep you regular; constipation is a common side effect of GLP-1 medications. It is usually easier to tolerate when you increase it gradually and drink enough water.
Nutritious in small servings
It provides protein, healthy fats, or other nutrients in a small volume. That is practical when you eat little and every bite needs to count.
High energy density
It has more than 300 kcal per 100 g: a lot of energy in a small volume, so it is less filling per calorie. That does not make it a bad food; when your appetite is very low, a small serving can help you meet your needs.

Frequently asked questions about hazelnuts

How much protein is in a 25 g (0.9 oz) serving of hazelnuts?

100 g (3.5 oz) of hazelnuts has 15 g of protein. A typical 25 g (0.9 oz) serving has about 3.8 g of protein. That is 2.4 g of protein per 100 kcal.

How many calories does a 25 g (0.9 oz) serving of hazelnuts have?

100 g (3.5 oz) of hazelnuts has 628 kcal. A typical 25 g (0.9 oz) serving has about 157 kcal. That is a very high energy density.

Does hazelnuts have fiber?

100 g (3.5 oz) of hazelnuts has 9.7 g of fiber. A typical 25 g (0.9 oz) serving has about 2.4 g of fiber. It carries our “High in fiber” tag.

Is hazelnuts filling?

Barely filling for the calories it provides: our estimated satiety score is 1 out of 5. Calculation: 1 (base) − 2 (very high energy density: 628 kcal/100 g) + 0 (protein: 2.4 g/100 kcal) + 0 (fiber: 1.5 g/100 kcal) + 0 (solid food with 5.3 g of water, under 70) = −1; raised to the minimum of 1. It is an estimate based on its composition, not a measurement in people.

What should I know about hazelnuts on a GLP-1 medication?

Based on our tags, this is what matters about hazelnuts on a GLP-1 medication. “High in fiber”: a good amount of fiber, which helps keep you regular; it is easier to tolerate when you increase it gradually and drink enough water. “Nutritious in small servings”: a lot of nutrition in a small volume, which is practical when you eat little. “High energy density”: a lot of energy in a small volume; when your appetite is very low, a small serving can help you meet your needs. These are general guidelines, not medical advice: everyone tolerates foods differently.

What counts as a normal serving of hazelnuts?

We use 25 g (0.9 oz) as a typical serving. That amount provides about 157 kcal, 3.8 g of protein, and 2.4 g of fiber. It is a reference for calculations, not a recommendation of how much to eat.

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Sources

Sources for the data on this page, with the access date.

  1. Official databaseU.S. Department of Agriculture, Agricultural Research Service.USDA FoodData Central: Nuts, hazelnuts or filberts (FDC ID 170581).accessed .
  2. Clinical guidelineObesity (Wiley).Mozaffarian D, et al. Nutritional priorities to support GLP-1 therapy for obesity: A joint Advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society. Obesity. 2025;33(8):1475-1503. doi:10.1002/oby.24336.accessed .
  3. Clinical trialInternational Journal of Environmental Research and Public Health (MDPI).Brown R, Gray AR, Chua MG, Ware L, Chisholm A, Tey SL. Is a Handful an Effective Way to Guide Nut Recommendations? Int J Environ Res Public Health. 2021;18(15):7812. doi:10.3390/ijerph18157812.accessed .
  4. RegulatorOfficial Journal of the European Union (EUR-Lex).Regulation (EC) No 1924/2006 on nutrition and health claims made on foods (Annex).accessed .
  5. RegulatorOfficial Journal of the European Union (EUR-Lex).Regulation (EU) No 1169/2011 on the provision of food information to consumers (Annex II, substances causing allergies or intolerances, and Annex XIII, nutrient reference values).accessed .
  6. RegulatorOfficial Journal of the European Union (EUR-Lex).Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods.accessed .
  7. RegulatorEuropean Commission.EU Register of nutrition and health claims made on foods.accessed .
  8. Meta-analysisAllergy (European Academy of Allergy and Clinical Immunology, Wiley).Spolidoro GCI, Lisik D, Nyassi S, et al. Prevalence of tree nut allergy in Europe: A systematic review and meta-analysis. Allergy. 2024;79(2):302-323. doi:10.1111/all.15905.accessed .
  9. InstitutionRoyal Spanish Academy and Association of Academies of the Spanish Language (RAE-ASALE).Diccionario de la lengua española (Dictionary of the Spanish Language, 23rd ed., online version): "avellana" (in Spanish).accessed .