Benefits Of Walnuts For Weight Loss

What are walnuts?

Walnuts are one of the most popular nuts, along with almonds, cashews and peanuts. Walnut is a tree nut with a brown-coloured kernel and a ridged surface which can resemble two halves of the brain. It has a bitter taste and can be eaten raw or cooked in either sweet or savoury dishes with it being especially popular in baking. Previous studies have shown that eating nuts can lower the risk of cardiovascular disease, such as heart disease, as well as lower blood pressure and cholesterol levels. Interestingly, although walnuts are both high in fats and calories, walnut consumption has been linked to weight loss along with various other health benefits.1 

Reasons why walnuts must be included in your diet for weight loss

Fat loss

Many studies have suggested that walnut consumption does not lead to weight gain but instead weight loss. Eating a handful of walnuts every day as part of a healthy diet can stimulate fat loss and help promote healthy body weight. 

Reduction in waist circumference

A study from 2017 found that a walnut-enriched diet led to a reduction in body weight and waist circumference.2

Reduce cardiovascular risk

Walnuts also lowered blood pressure, which was maintained at 6 months and reduced total cholesterol and low-density lipoprotein (LDL) cholesterol, which are all risk factors for cardiovascular disease. 1  

Healthy fat

One of the reasons walnuts are great for weight loss is because they are a good source of unsaturated fats, also known as healthy fat.

The difference between healthy fat and unhealthy fat often causes confusion. A small amount of fat is important for our bodies as a part of a healthy, balanced diet, but too much fat, especially saturated fat, can be bad for our health. Sources of saturated fat include butter, cheese, cream, cakes, biscuits and pastries and eating too much can increase the levels of LDL cholesterol in your blood (bad cholesterol) which can increase the risk of heart disease and stroke. Unsaturated fats such as polyunsaturated fat are mostly found in oils from fish and plants and some nuts. This is also known as healthy fat as it can lower bad cholesterol levels and reduce your risk for heart disease. 

Although most nuts contain monounsaturated fat, it is interesting to know that only walnuts have mainly polyunsaturated fat. A 30g serving of walnuts contains around 14g of polyunsaturated fat. A study involving overweight women compared the weight loss effects between a walnut-rich or higher monounsaturated fat diet and a low-fat diet. The scientists discovered that the walnut-rich diet caused greater weight loss at 12 months compared to the low-fat diet. This degree of weight loss has been shown to reduce the risk of type 2 diabetes and cardiovascular disease, including heart disease.

Appetite control

As mentioned above, walnuts are high in polyunsaturated fats, which is known to have a greater effect on appetite control compared to other fats. This healthy fat is more satiating and it therefore has a greater influence on certain hunger hormones, which means you will be kept full for longer. A study involving participants aged between 18-35 years found that when they regularly consumed a diet high in polyunsaturated fats they had a significant decrease in fasting ghrelin. This is a hormone that increases the feeling of hunger in our body. They also had a significant increase in peptide YY (PYY), a hormone that works to increase fullness or satiety.

Other health benefits of walnut

Heart health

Research shows that walnut consumption is linked to a lower risk of cardiovascular disease. This is because including walnuts in your diet can lower the risks of cardiovascular disease. Several studies have shown that eating walnuts as part of a healthy diet can increase high-density lipoprotein (HDL) cholesterol, decrease total and low-density lipoprotein (LDL) cholesterol and reduce inflammation, blood pressure and plaque formation. Therefore, these findings concluded that eating around 43 g of walnuts per day as part of a healthy diet consisting of low saturated fat and low cholesterol can reduce the risk of coronary heart disease.

Brain health

Several studies show that walnut consumption has beneficial effects on cognitive function and brain health. Not only are walnuts high in omega-3 fatty acids, they also have a high content of antioxidants, including flavonoids, phenolic acid and vitamin E. In fact, walnuts was ranked second out of 1113 different foods based on its contents of antioxidants. Moreover, out of all dry fruits, walnut has the best antioxidant efficacy, which is then followed by almonds, cashews and raisins.3

Antioxidants protect the body against oxidative stress caused by free radicals. If unprotected, oxidative stress can lead to cell death. The brain is especially vulnerable to oxidative stress as it consumes 20% of the total body intake of oxygen and it has a limited capacity for antioxidants. Oxidative stress is linked with many diseases and disorders such as Alzheimer’s disease, mild cognitive impairment (MCI), the ageing process and other brain disorders. Walnuts reduce oxidative stress by decreasing free radicals and boosting antioxidant defence.3

In addition, a mice study found that long-term supplementation of walnuts included in their diet significantly improved memory, motor coordination, learning skills and anxiety-related behaviour. Overall, many studies on the topic of walnuts and brain health have concluded that walnuts have the ability to maintain cognitive function, provide protection against age-related cognitive decline and reduce the risk or delay the onset of cognitive impairment and dementia in MCI and Alzheimer’s disease.3

Improves digestive system

Eating walnuts has been found to support a healthy digestive system. A recent study on rats involved two groups with one eating a walnut-rich diet and the other group eating a replacement diet without any walnuts. After 10 weeks, the walnut-rich diet enriched the gut microbiota of the rats, which is the community of microorganisms that live in our intestines. In particular, walnut consumption increased the abundance of probiotic bacteria, which is the ‘good’ bacteria that is beneficial for our health.4

Nutritional facts 

A 30g serving of walnuts contains:

  • 206 kcal/ 851 KJ
  • 1.4 g Fibre
  •  4.4 g Protein
  • 20.6 g Fat
  • 14 g Polyunsaturated fat
  • 48 mg Magnesium
  • 135 mg Potassium
  • 114 mg Phosphorus
  • 28 mg Calcium
  • 20 mcg Folate. 

Side effects and other concerns

There are some side effects of eating walnuts, which include the following.

Allergic reactions 

Allergy symptoms usually appear within minutes but if you experience an adverse reaction, you should contact your GP. A severe reaction, known as anaphylaxis, requires immediate medical attention.


Young children and adults with swallowing problems should avoid eating walnuts due to the risk of choking.

Digestive issues

Although walnuts can treat digestive issues, sometimes they can make them worse. Symptoms include bloating, stomach pain and diarrhoea.

May aggravate ulcers

Walnuts are high in fibre and so may aggravate ulcers in certain people. 


Overall, walnuts are a tree nut with fantastic health benefits and can be a great addition to your diet if you plan to lose weight. Walnuts have a high content of polyunsaturated fat, which is also known as healthy fat that can keep you full and satisfied for longer. In addition to their beneficial effects on weight loss, walnuts are also beneficial for brain and heart health. Walnuts are a great source of antioxidants which can protect the brain against disorders such as MCI and Alzheimer’s disease. Walnuts are also linked to a lower risk for cardiovascular disease and many studies have shown that they increase ‘good’ HDL cholesterol levels and decrease ‘bad’ LDL cholesterol levels as well as decrease other risk factors for cardiovascular disease. Luckily, walnuts are widely available and easy to add to your diet. They are available in most supermarkets and can be eaten as a snack or added to a range of dishes. Scientists are still uncovering the many health benefits of walnuts so adding them to your diet is an excellent idea. 


  1. Rock CL, Flatt SW, Barkai HS, Pakiz B, Heath DD. Walnut consumption in a weight reduction intervention: effects on body weight, biological measures, blood pressure and satiety. Nutr J [Internet]. 2017 Dec 4 [cited 2023 Jan 6];16:76. Available from:
  2. Rock CL, Flatt SW, Pakiz B, Quintana EL, Heath DD, Rana BK, et al. Effects of diet composition on weight loss, metabolic factors and biomarkers in a 1-year weight loss intervention in obese women examined by baseline insulin resistance status. Metabolism [Internet]. 2016 Nov [cited 2023 Jan 6];65(11):1605–13. Available from:
  3. Chauhan A, Chauhan V. Beneficial effects of walnuts on cognition and brain health. Nutrients [Internet]. 2020 Feb 20 [cited 2023 Jan 6];12(2):550. Available from:
  4. Byerley LO, Samuelson D, Blanchard E, Luo M, Lorenzen BN, Banks S, et al. Changes in the gut microbial communities following addition of walnuts to the diet. J Nutr Biochem [Internet]. 2017 Oct [cited 2023 Jan 6];48:94–102. Available from:
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

Get our health newsletter

Get daily health and wellness advice from our medical team.
Your privacy is important to us. Any information you provide to this website may be placed by us on our servers. If you do not agree do not provide the information.

Suad Mussa

Bachelor of Science – BSc, Biology. Queen Mary University of London

Suad Mussa is a biology graduate with a strong passion for medical writing and educating the public about health and wellbeing. presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
Klarity is a citizen-centric health data management platform that enables citizens to securely access, control and share their own health data. Klarity Health Library aims to provide clear and evidence-based health and wellness related informative articles. 
Klarity / Managed Self Ltd
Alum House
5 Alum Chine Road
Westbourne Bournemouth BH4 8DT
VAT Number: 362 5758 74
Company Number: 10696687

Phone Number:

 +44 20 3239 9818