Are macadamias fattening?
No. Decades of research shows that people who eat nuts tend to have lower body weights and gain less weight over time73,74,75,76,77,78,79. The largest review on nuts and weight, of 86 clinical trials and six long-term studies, found regular nut consumption as part of a healthy diet contributes to heart health without causing weight gain73.
Researchers have identified several reasons why nuts, such as macadamias, don’t cause weight gain:
- They satisfy hunger, and as a result, people tend to eat fewer calories later6
- Their fat (and therefore, kilojoule) content is not fully absorbed by the body81
- They contain dietary fibre which may influence the gut microbiome and therefore metabolism10
- They improve how the body handles glucose and insulin, which helps regulate weight82
- They may help reduce inflammation in the body, which in turn helps protect against weight gain83,84
To understand more, take a look at this video about nuts and weight management.
Adding a handful of macadamias to your diet instead of less nourishing foods such as cakes, cookies, confectionery, soft drinks and alcohol is a great way to add nutrients to your diet for overall good health.
I have high cholesterol. Can I eat macadamias?
Yes! Studies have shown that macadamias lower the ‘bad’ (LDL) cholesterol in the blood74,85. If you have high cholesterol, eating a handful of macadamias regularly as part of a heart-healthy diet is an effective and enjoyable way to reduce it. The combination of good fats, fibre and plant sterols make macadamias an excellent choice to help prevent and reduce high cholesterol levels.
For more information, take a look at this video explaining nuts and cholesterol reduction.
Are macadamias good for heart health?
Yes! Macadamias contain a healthy combination of protective nutrients for the heart86,87 so every handful is doing you good. The oil in macadamias is the healthy unsaturated kind (mostly monounsaturated) that helps maintain ideal cholesterol levels88,89. They also contain natural plant sterols which benefit cholesterol levels90, as well as arginine, an amino acid which helps maintain healthy blood vessels84.
To understand more, take a look at this video on nuts and heart disease or read more about the heart-healthy benefits of Australian macadamias.
How do macadamias affect blood glucose?
Macadamia nuts contain very small amounts of carbohydrate, and are rich in heart-healthy monounsaturated fat, protein and dietary fibre. This combination supports a slower and smaller overall rise in blood glucose levels after eating.
Too many nutrient-poor, highly-processed carbohydrate-containing foods can upset your metabolism and lead to high blood glucose levels. Nuts like macadamias can work against this.
When added to carbohydrate-containing meals or snacks, macadamias actually reduce blood glucose levels20. For example, white bread has a high glycaemic index (GI), meaning that it quickly raises blood glucose levels, but spreading the same white bread with macadamia butter reduces the GI. Better still, eating a handful of macadamias instead of the white bread doesn’t increase blood glucose levels at all.
For many people whose insulin is not working as it should (called insulin resistance), nuts are an ideal snack and a healthy addition to meals. To find out more about GI, go to glycemicindex.com.
Are macadamias good for diabetes?
Macadamias are an ideal food for people with diabetes and pre-diabetes91. A review of studies found that eating nuts helps improve glycemic control (blood glucose levels) in people with type 2 diabetes92. Adding nuts to carbohydrate-rich foods actually lowers the glycemic index (GI) of that meal or snack, which is good news for people with diabetes20.
Nuts help with diabetes prevention as well93. An analysis of multiple studies involving 500,000 people found eating 30g of nuts four times a week reduced the risk of developing type 2 diabetes by 13%94. People with diabetes or pre-diabetes are at greater risk of heart disease95. The heart-healthy nutrients in nuts like macadamias can help support the heart health of those living with these conditions86,87,96.
For more information, take a look at this video explaining the benefits of macadamias and diabetes management or read more about the diabetes-friendly characteristics of Australian macadamias.
Are macadamias good for gut health?
Fibre is essential for good gut health and macadamias contain around 2.5g of dietary fibre per handful (or 30g serve)3, which is similar to the amount of fibre in a slice of wholemeal bread. Fibre not only helps to maintain good bowel and gut health but good blood cholesterol levels too97.
Macadamia nuts make the perfect gut-friendly snack because they are high in healthy monounsaturated fats and low in sugar. Diets high in refined sugars and low in nutrients can be associated with poor gut health, but research shows a Mediterranean-style diet that includes nuts can be good for gut health, influencing overall health98,99.
Read more about how macadamias impact gut health.
Aren’t raw macadamias better for you than roasted ones?
Roasted macadamias still offer the same health benefits as raw ones. Some people assume roasting nuts adds more fat but even if they are roasted in oil, very little is absorbed into the nut. And dry-roasting adds nothing but extra flavour!
On the technical side, heating or cooking any food slightly reduces the levels the heat-sensitive vitamins, like B-group vitamins and vitamin E, but roasting macadamias can also concentrate nutrient levels, particularly minerals, by reducing the water content. Both raw and roasted macadamias are good for you, so feel free to enjoy whichever you prefer!
How can macadamias support brain health?
Your brain is the command centre for your entire nervous system. It helps you think, remember, feel and move. Macadamias contain healthy unsaturated oils, fibre and plant sterols that help maintain optimal blood supply throughout the whole body, including the brain.
Macadamias contain vitamin B1 (thiamine) that is essential for the proper functioning of your nervous system. Macadamias are also naturally endowed with helpful phytochemicals including antioxidants. These nutrients are thought to help protect the brain from damage over time (neurodegeneration). Studies of large groups of people around the world have found that eating nuts reduces the risk of stroke87,100,101, and eating nuts regularly may also boost cognitive function in old age45,51,52.
Another aspect of brain health is our mental health. The well-known SMILES trial showed that eating a Mediterranean-style diet, including daily nuts, can help reduce depressive symptoms56. This makes eating macadamias a good mood food.
How many macadamias is it healthy to eat?
A healthy handful of macadamias is about 30g or 15 whole nuts. We should all strive to eat at least one healthy handful of nuts per day. But there’s no reason why you can’t eat more.
Several studies have shown that 30g of nuts a day will provide heart-health benefits without weight gain73,100,102. Other research suggests that two handfuls can help with lowering cholesterol103 and eating up to four handfuls won’t make you gain weight73,76. So depending on what your nutrient needs are, you may want to eat more than just a handful as part of your varied and balanced diet.
Can eating macadamias reduce the risk of cancer?
No single food can prevent, treat or cure cancer. However, a healthy lifestyle with a balanced diet including nuts, such as macadamias, and regular exercise may reduce your risk. Cancer organisations around the world recommend enjoying a mostly plant-based diet (based on whole grains, vegetables, legumes, fruits, nuts and seeds). Regular exercise and limiting salt and alcohol are also key steps you can take to reduce your risk of cancer104.
When it comes to nuts, like macadamias, a large review study found that eating a handful a day to be linked with an 11% lower risk of dying from cancer, compared with not eating nuts100. Other recent studies support a protective role of nuts in lowering cancer risk105,106.
We know that including more plant foods in the diet introduces more antioxidants into your body. This helps reduce the damage caused by oxidative stress and free radicals that may contribute to the risk of cancers. Macadamia nuts contain many beneficial antioxidant compounds.
For more information on reducing your risk of cancer visit The Cancer Council.
I eat my macadamias salted – are they still good for me?
Macadamias are a naturally nutritious, whole food with many health benefits. You’ll still get all the same nutrients from salted macadamias, yet we know that too much sodium (salt) in the diet is unhealthy because it can contribute to high blood pressure and an increased risk of heart disease and stroke.
So in general, dietitians and nutritionists recommend you choose unsalted nuts as your ‘everyday’ nuts, and keep salted nuts for special occasions only. And remember that you can add fantastic flavour to macadamias by using herbs and spices or roasting them in the oven.
Can macadamia nuts be eaten as part of a low FODMAP diet?
Yes. Macadamia nuts are one of the low FODMAP nuts. You can eat around 50g or 20 nuts for them to still be considered low FODMAP.
FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols.
Some foods are high in these short-chain carbohydrates that are poorly digested in the small intestine. They then pass to the large intestine where bacteria ferment them. This produces gas, which for some people can be uncomfortable and cause pain. For more about FODMAP, see Monash University’s webpage or read our article on how macadamias fit in to a low FODMAP diet.
In general, a low FODMAP diet should not be long term and it is best to have an Accredited Practising Dietitian assist you if considering this diet.
What are ‘core foods’?
Core foods are nutrient-rich foods we need to eat every day for health and wellbeing.
There are five core food groups:
- Vegetables, including legumes/beans
- Grains, cereal foods, mostly wholegrain and/or high fibre varieties, such as breads, cereals, rice, pasta, noodles, polenta, couscous, oats, quinoa and barley
- Fruits
- Meat and alternatives, including lean meats and poultry, fish, eggs, tofu, nuts and seeds and legumes/beans
- Dairy foods and alternatives, including milk, yoghurt, cheese and/or alternatives, mostly reduced fat
Macadamias fall into the ‘Meat and alternatives’ group of core foods so are ideal for meat-free meals. Enjoying a handful of macadamias as a snack instead of salty, highly-processed snacks or chocolate bars is a delicious way to include more nutritious core foods in your diet.
For more information about healthy eating and the food groups visit Eat for Health (Australia), NHS Live Well (UK), My Plate (USA).
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