Walnuts are among the oldest tree foods grown by man, with their importance being highlighted back in 7000 B.C. Today, due to diet restrictions and several disbeliefs people avoid eating walnuts considering that they are calorie-rich and fat dense in nature. However, the fact that walnuts are immensely rich in nutrition and their benefits ranging from metabolism to heart health and beauty cannot be overlooked.
Here are top 10 reasons walnuts must be included as a part of healthy diet.
1# Helps weight loss: Contrary to what people believe, walnuts can form a part of weight management diet. Several studies have suggested that regular consumption of walnuts is unlikely to cause weight gain or obesity. In fact, an ounce of walnuts contains 2.5g of omega 3 fats, 4g of protein and 2g of fibre that help provide satiety. Any successful weight management plan must include satiety factor; so walnut is undoubtedly the right food to consider if you are into a weight management programme. Despite being 'dense in calories, walnuts can be an important tool in helping you lose weight.
2# Induces sleep: Walnuts contain a compound called melatonin, responsible for conveying messages regarding the cycle of light and dark to the body. Since melatonin is already synthesised by the body, consumption of walnuts increases the blood levels of melatonin, thereby inducing sleep. That's why eating walnuts can be a great way to improve sleep. 
3# Great for your hair: Walnut is a good 'hair food' too. This is because walnuts contain biotin (vitamin B7) that helps strengthen hair, reduce hair fall and improve hair growth to certain extent. In addition to walnuts, you can try these foods to prevent hair loss.
4# Prevents heart disease: Among all the dietary plants and nuts, walnuts contain the highest amount of antioxidants. Around 100 g of walnuts will give more than 20 mmol antioxidants, which makes them extremely effective in combating heart disease by their ability to destroy free radicals. They are also loaded with omega-3 fatty acids that lowers bad cholesterol and increases the production of good cholesterol making it a great snack to keep your heart in great health. 
5# Prevents diabetes: All types of nuts are associated with a lowered risk of diabetes and walnuts are no exception. According to a study, women who consumed 28 grams of walnuts twice a week were 24% less likely to develop type 2 diabetes. The study was published in the Journal of Nutrition, and even though it was conducted on women, experts believe that the benefits would be similar for men too. 
6# Boosts your sperm quality: Eating 2.5 ounces of walnuts per day improves semen quality in healthy young men, researchers say. According to a study by UCLA researchers, eating 75 grams of walnuts a day improves the vitality, motility, and morphology of sperm in healthy men aged 21 to 35 . Here are 8 easy ways to boost your sperm quality and count.
7# Makes your skin glow: Walnuts are rich in B-vitamins and antioxidants that prevents your skin from free radical damage and prevents wrinkles and signs of ageing. So if you want glowing skin long into your middle-age, eat walnuts.
8# Can keep dementia at bay: Eating walnuts everyday can help ward off dementia, say scientists. In the study, Dr. Abha Chauhan and his team from the New York State Institute found that mice deprived of walnuts suffered a dramatic loss in learning, memory and physical and emotional control. According to the results, vitamin E and flavanoids in walnuts helped destroy harmful free radical chemicals that cause dementia. You may read more to find out how walnuts help prevent Alzheimer's. Also read how walnuts help you keep your brain healthy.
9# Prevents pancreatic cancer: A new study has found that consumption of nuts, including walnuts, is inversely associated with risk of pancreatic cancer, independent of other potential risk factors for pancreatic cancer. Researchers looked at the association between nut consumption and risk of pancreatic cancer among 75,680 women in the Nurses' Health Study, with no previous history of cancer. It was observed that the women who consumed a one-ounce serving of nuts two or more times per week had a significantly reduced risk of pancreatic cancer compared to those who largely abstained from nuts.
10# Helps you live longer: Eating a handful of walnuts just thrice a week is the key to a longer life, a study has found. Scientists discovered that these edible seeds cut the risk of dying from cancer by 40 per cent and from cardiovascular disease by at least 55 per cent. In general, nut eaters in the research had a 39 per cent lesser risk of death and walnut eaters in particular a 45 per cent reduced threat. Also read the health benefits of green, leafy vegetables.
11# Great for pregnant women: Mothers-to-be who eat a diet rich in fatty acids such as those found in walnuts can reduce the baby's chances of developing food allergies, researchers say. The research found that if a mother's diet contains a certain group of polyunsaturated fatty acids (PUFAs), the baby's gut develops differently. The PUFAs are thought to improve how gut immune cells respond to bacteria and foreign substances, making the baby less likely to suffer from allergies.
12# Reduces breast cancer risk: The researchers at the Marshall University found that a daily dose of walnuts – equal to 2 ounces a day in humans – reduces the growth of breast cancer tumours in mice. Lead researcher Elaine Hardman, Ph.D., of Marshall's Joan C. Edwards School of Medicine, and colleagues studied the mice from the mother, through conception and throughout life. They then compared mice given walnuts to those fed a regular diet. The research found that the group whose diet included walnut at both stages developed breast cancer at less than half the rate of the group with the typical diet. In addition, the number of tumours and their sizes were significantly smaller.
13# Can fight stress: If daily stress is taking a toll on your health, it's time to eat walnuts, as they help fight stress, according to a study. The researchers found that including walnuts and walnut oil in the diet lowered both resting blood pressure and blood pressure responses to stress in the laboratory. Walnuts are a rich source of fibre, antioxidants, and unsaturated fatty acids, particularly alpha linolenic acid, an omega-3 fatty acid. These are the nutrients that give walnuts it's stress fighting properties.