Frequently Asked Questions
Are macadamias fattening?
No. People who eat nuts actually tend to have lower body weights and gain less weight over time15,16
. A review of 82 studies found regular nut consumption as part of a healthy diet contributes to heart health without causing weight gain17
. Researchers have identified several reasons why nuts such as macadamias don’t cause weight gain.
• They satisfy hunger and reduce appetite 18,19
• They don’t increase blood glucose and insulin levels, 20
• Their kilojoule content is not fully absorbed 21
Take a look at this video
about nuts and weight management.
Adding macadamias to your eating plan is a great way to add nutrients and the right kinds of fats for good health. You can include a handful of macadamias (around 30g) in your kilojoule-controlled eating plan, but eat them instead of less healthy foods such as cakes, cookies, confectionery, soft drinks and alcohol.
What are ‘core foods’?
Core foods are nutrient-rich foods we need to eat every day for health and wellbeing. Macadamias fall into the meat and alternatives group and are ideal for meat-free meals. Enjoying a handful of macadamias as a snack instead of salty packet snacks or chocolate bars is a delicious way to include more nutritious core foods in your diet.
The core food groups
• Vegetables and legumes/beans
• Grain (cereal) foods mostly wholegrain and/or high fibre varieties, such as breads, cereals, rice, pasta, noodles, polenta, couscous, oats, quinoa and barley
• Lean meats and poultry, fish, eggs, tofu, nuts and seeds and legumes/beans
• Milk, yoghurt, cheese and/or alternatives, mostly reduced fat
I have high cholesterol - can I eat macadamias?
Yes! In fact macadamias are proven to lower the bad LDL cholesterol in the blood in scientific studies22
. 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 get it down. The combination of good fats, fibre and plant sterols make macadamias an excellent choice in a cholesterol-lowering diet. 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 heart23
so every handful is doing you good. The oil in macadamias is the healthy unsaturated kind that helps maintain ideal cholesterol levels24
and they contain natural plant sterols, which benefit cholesterol as well25
. Macadamias also contain an amino acid called arginine, which helps maintain healthy blood vessels26
. Take a look at this video
on nuts and heart disease.
How do macadamias affect blood glucose?
Too many refined carbohydrate foods with a high glycemic index (GI) upset the metabolic applecart and can lead to high blood glucose levels. Nuts are perfect for taking the load off. When added to meals or snacks they actually reduce blood glucose levels due to their healthy oils, protein and fibre 27
. For example, white bread has a high GI, 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 (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-diabetes. A review of studies found eating nuts helps improve glycemic control (blood glucose levels) 28
. in people with type 2 diabetes. Adding nuts to carbohydrate-rich foods actually lowers the glycemic index (GI) of that meal or snack, and that’s a good thing29
. People with diabetes or pre-diabetes are unfortunately at greater risk of heart disease, so the combination of heart-friendly nutrients in nuts such as macadamias also help on this front30
. Nuts help with prevention as well. An analysis of many studies involving 500,000 people found eating 30g of nuts four times a week reduced the risk of developing type 2 diabetes by 13%31. Take a look at this video
explaining the benefits of macadamias and diabetes management.
Are macadamias good for digestive health?
Macadamias contain around 2g fibre per 30g serve, which is similar to the amount in a slice of wholemeal bread. Fibre not only helps to maintain good bowel health but also good blood cholesterol levels.32
Aren’t raw macadamias better for you than roasted ones?
Both raw and roasted nuts are good for you so enjoy whichever you prefer. Some people assume roasting nuts adds more fat but even if they are roasted in oil, very little actually gets in. Of course dry-roasting adds nothing but extra flavour! On the technical side, heating or cooking any food slightly reduces the levels the heat-sensitive B-vitamins, but on the other hand roasting macadamias actually concentrates nutrient levels by reducing the water content. Roasted macadamias still offer the same health benefits as raw ones.
How can macadamias support brain health?
Macadamias contain healthy unsaturated oils, fibre and plant sterols. These nutrients help maintain optimal blood supply throughout the whole body, including the brain. Macadamias are naturally free of nasty trans-fats that have been linked to the development of depression33
. Your brain is the command centre for your entire nervous system that helps you think, remember, feel and move. Macadamias contain of vitamin B1 (thiamine) and this B-group vitamin is essential for the proper functioning of your nervous system. Macadamias are naturally endowed with helpful phytochemicals including antioxidants. These nutrients are thought to help protect the brain from the damage over time (neurodegeneration)34
. Studies of large groups of people around the world have found eating nuts reduces the risk of stroke35,36,37
and eating nuts regularly may also boost cognitive function in old age38
How many macadamias is it healthy to eat?
You could eat a handful of macadamias (about 30g, 15 whole nuts) every day if you like. A review of studies suggests 30g of nuts a day will provide heart health benefits without weight gain39
Can eating macadamias reduce the risk of cancer?
No single food can help prevent, treat or cure cancer but a healthy lifestyle with a balanced diet including nuts such as macadamias and regular exercise may help prevent it. Cancer organisations around the world recommend maintaining a healthy weight, enjoying a mostly plant-based diet (based on grains, vegetables, legumes, fruits, nuts and seeds with small amounts of lean meats, poultry, fish and reduced fat dairy foods), regular exercise and limiting alcohol as key steps you can take to reduce your risk of cancer40
. For more information on reducing your risk of cancer visit The Cancer Council.
I eat my macadamias salted – are they still good for me?
This is a tricky question! Macadamias are a naturally nutritious whole food with many health benefits, yet we know that too much sodium (salt) in the diet is unhealthy because it increases blood pressure and increases heart disease risk. The evidence so far suggests you may be better off eating salted nuts than no nuts at all. The large population studies that have found nut consumption reduced the risk of disease did not ascertain whether the nuts were salted or not and we can assume from currently available nut products that most nuts eaten in the studies were also salted. To keep your blood pressure ideal and look after your heart, eat nuts such as macadamias regularly (ideally unsalted) and try to minimise the amount of added salt in the foods you prepare and buy. You can add fantastic flavour to macadamias using herbs and spices.
15. Rocha, M., et al., A review on the role of phytosterols: new insights into cardiovascular risk. Curr Pharm Des, 2011. 17(36): p. 4061-75.
16. Boger, R.H., The pharmacodynamics of L-arginine. Altern Ther Health Med, 2014. 20(3): p. 48-54.
17. Neale, E., D. Nolan-Clark, and L. Tapsell, The effect of nut consumption on heart health:a systematic literature review. 2015. Nuts for Life, unpublished.
18. Estruch, R., et al., Effect of a high-fat Mediterranean diet on bodyweight and waist circumference: a prespecified secondary outcomes analysis of the PREDIMED
19. Kim E, Ko HJ, Jeon SJ, et al. The memory-enhancing effect of erucic acid on scopolamine-induced cognitive impairment in mice. Pharmacol Biochem Behav. 2016;142:85-90. doi:10.1016/j.pbb.2016.01.006
20. O’BRIEN J, OKEREKE O, DEVORE E, ROSNER B, BRETELER M, GRODSTEIN F. LONG-TERM INTAKE OF NUTS IN RELATION TO COGNITIVE FUNCTION IN OLDER WOMEN. J Nutr Health Aging. 2014;18(5):496-502. doi:10.1007/s12603-014-0014-6
21. Koyama AK, et al. Evaluation of a Self-Administered Computerized Cognitive Battery in an Older Population. Neuroepidemiology, 2015. 45(4): p.264-72.
22. Viguiliouk E et al. Effect of tree nuts on glycemic control in diabetes: a systematic review and meta-analysis of randomised controlled trials. PLoS One 2014;9(7):e103376
23. Grodstein F. Cardiovascular risk factors and cognitive function. Alzheimers Dement. 2007;3(2 Suppl):S16-22. doi:10.1016/j.jalz.2007.01.001
24. Nishi SK et al. Nut consumption, serum fatty acid profile and estimated coronary heart disease risk in type 2 diabetes. Nutr Metab Cardiovasc Dis. 2014 Aug;24(8):845-52
25. Afshin A, et al. Am J Clin Nutr. 2014 Jul;100(1):278-88
26. Fleischer, D.M., Conover-Walker, M.K., Matsui, E.C. and Wood, R.A. The natural history of tree nut allergy. Journal of Allergy and Clinical Immunology. 2005 Nov;116(5):1087-93
27. Allen KJ, Hill DJ, Heine RG. Food allergy in childhood. Med J Aust. 2006;185:394–400.
29. Jacka FN, et al. A randomised controlled trial of dietary improvement for adults with major depression (the ‘SMILES’ trial). BMC Medicine, 2017. 15(1): p.23.
30. Disease in Hypercholesterolemic Subjects. Lipids. 2007;42(6):583-7
32. Martinez-Gonzalez, M.A. et al. Nut consumption, weight gain and obesity: Epidemiological evidence. Nutr Metab Cardiovasc Dis. 2011;21 Suppl 1:S40-5.
33. Flores-Mateo G et al Nut intake and adiposity: meta-analysis of clinical trials. Am J Clin Nutr. 2013;97(6):1346-55
34. Nuts and the big fat myth. The positive role for nuts in weight management. Available from URL https://nutsforlife.com.au/wp-content/uploads/pdf/major-reports/Nuts_Weight%20Report_2016_20pp%20low%20res%20FINAL%20APPROVED.pdf
35. Pereira, M.A. et al. Dietary fiber and body-weight regulation. Observations and mechanisms. Pediatr Clin North Am. 2001;48(4):969-980
36. Casas-Agustench, P. et al. Nuts, inflammation and insulin resistance. Asia Pac J Clin Nutr. 2010;19(1):124-130.
37. Mattes, R.D. The energetics of nut consumption. Asia Pac J Clin Nutr. 2008;17 Suppl 1:337-9
38. Wang X, Zhang A, Miao J, et al. Gut microbiota as important modulator of metabolism in health and disease. RSC Adv. 2018;8(74):42380-42389. doi:10.1039/C8RA08094A
39. Griel AE, Cao Y, Bagshaw DD, Cifelli AM, Holub B, Kris-Etherton PM. A macadamia nut-rich diet reduces total and LDL-cholesterol in mildly hypercholesterolemic men and women. J Nutr. 2008;138(4):761-7.
40. Del Gobbo LC, Falk MC, Feldman R, Lewis K et al. Effects of tree nuts on blood lipids, apolipoproteins, and blood pressure: systematic review, meta-analysis, and dose-response of 61 controlled intervention trials. Am J Clin Nutr 2015;102(6):1347-56. Available at URL https://www.ncbi.nlm.nih.gov/pubmed/26561616