They are high in monounsaturated and polyunsaturated fats and omega- 3 fatty acids. They are also a good source of protein.

Nuts have a reputation for being a high-calorie and high-fat food. However, they are dense in nutrients and provide heart-healthy fats.

The combination of healthy fats, protein, and fiber in walnuts helps to increase satisfaction and fullness. This makes them more healthful as a snack, compared with chips, crackers, and other simple carbohydrate foods.

NUTRITION:
According to the U.S. Department of Agriculture (USDA) National Nutrient Database, 1 cup of unbranded, organic walnuts (30 grams) contains:

• Energy: 200 calories 
• Carbohydrate 3.89 grams (g)  
• Sugar: 1 g
• Fiber: 2 g
• Protein: 5 g
• Fat: 20 g
• Calcium: 20 milligrams (mg)
• Iron: 0.72 mg
• Sodium: 0 mg

• manganese
• copper
• magnesium
• phosphorus
• vỉamin B6 
• iron

References:
What are the health benefits of walnuts?
Link: https://www.medicalnewstoday.com/articles/309834#health_benefits