Macadamia nuts hold more fat than any other nut on this site: 75.8 g per 100 g, which is 91% of their calories. Most of it is monounsaturated, 58.9 g per 100 g, the most of any of the 123 foods in our database.
They also have little protein, 7.9 g per 100 g against 9.2 g for pecans. So a 1-ounce (28 g) serving gives 204 calories and only 2.2 g of protein.
One fat sets them apart: palmitoleic acid, estimated at about 13 g per 100 g. In the one trial that tested it on its own, it raised LDL (“bad”) cholesterol like a saturated fat. Yet trials of whole macadamias lowered LDL when the nuts replaced foods high in saturated fat.
An ounce also gives 51% of the Daily Value (the daily target on US food labels) for manganese and 28% for vitamin B1 (thiamin).
The shell is the toughest part, needing about 2,000 newtons of force to crack. The nuts are also toxic to dogs, even though people eat them freely.
Health benefits of macadamia nuts
The top findings from 15 studies, strongest evidence first
What the stars mean
- Strong. Several randomized trials, pooled in a meta-analysis, point the same way, or regulators (FDA or EFSA) have approved the claim.
- Moderate. Good randomized trials support it, but there are fewer of them, or their results vary.
- Limited. Small, short or single trials, or mixed results. Promising, but it needs confirmation.
Population and lab studies get no stars: they show a link or a mechanism, not proof.
How we rate evidence →- ★★★Lower “bad” LDL cholesterol with nuts in generalAcross 61 trials, one daily ounce of tree nuts lowered it (by 4.8 mg/dL). In another pooled study, about 67 g of nuts a day lowered it by 7.4%.
- ★Lower LDL cholesterol in small macadamia trialsIn 25 people with mildly high cholesterol, a macadamia-rich diet lowered LDL from 3.44 to 3.14 mmol/L over 5 weeks. In another small trial, it lowered LDL about as much as a low-fat diet.
- ★No change in weight or body fatIn 35 overweight or obese adults, eating macadamias for about 15% of daily calories for 8 weeks did not change weight or body fat. Blood sugar measures did not change either.
- ★Mid-morning macadamia snack raised insulin resistanceIn 17 healthy women, a 70-calorie macadamia snack at 10:30 raised insulin resistance (the body responding less well to insulin) after lunch, versus no snack. It was a small study of single snacks.
- Population studyLinked to lower heart disease and death riskEach extra 28 g of nuts a day was linked to 0.71 times the risk of coronary heart disease. It was also linked to 0.78 times the risk of dying. The studies covered nuts in general.
All 15 studies, strongest evidence first
One daily ounce of tree nuts lowered LDL by 4.8 mg/dL
This meta-analysis (a study that pools earlier trials) combined 61 controlled trials with 2,582 adults, lasting 3 to 26 weeks. Macadamia nuts were one of eight tree nuts included, and the abstract gives no results for macadamias alone. Per 1-ounce (28.4 g) serving, total cholesterol fell 4.7 mg/dL and triglycerides 2.2 mg/dL. The authors found no clear difference by nut type, and stronger effects at 60 g of nuts a day or more.
Nuts, about 67 g daily, lowered LDL by 10.2 mg/dL (7.4%)
This pooled analysis used individual data from 25 trials in 7 countries, with 583 people who were not taking cholesterol drugs. Total cholesterol fell 10.9 mg/dL, the effect grew with the dose, and different types of nuts had similar effects. It was largest in people with high starting LDL or a lower body mass index. It covers nuts as a group, and the abstract does not name macadamias.
Tree nuts and peanuts lowered LDL, total cholesterol and triglycerides
This review covered 139 randomized trials of tree nuts and peanuts combined, 129 of them in the meta-analysis. Cholesterol ratios and apolipoprotein B fell too. The authors rate the certainty as moderate for those ratios and apoB, low for triglycerides and very low for LDL and total cholesterol. The low ratings came because results varied and publication bias (missing negative studies) was likely. The abstract does not split results by nut.
A macadamia-rich diet lowered LDL from 3.44 to 3.14 mmol/L
In this randomized crossover feeding trial, 25 people with mildly high cholesterol ate each diet for 5 weeks. The macadamia diet had 42.5 g (1.5 ounces) of nuts a day and 7% saturated fat. The comparison was an average American diet with 13%. Total cholesterol fell from 5.45 to 4.94 mmol/L (a unit for blood levels), and triglycerides did not change.
Macadamias lowered LDL about as much as a low-fat diet
In this randomized crossover trial, 30 volunteers aged 18 to 53 ate three 30-day diets. These were a typical American diet, an American Heart Association Step 1 diet (30% of energy from fat) and a macadamia-based diet (37% from fat). On the macadamia diet, LDL fell to 3.22 from 3.37 mmol/L. Total cholesterol was 5.20, 4.99 and 4.95 mmol/L. HDL cholesterol was slightly lower on both other diets (1.34 and 1.37 against 1.43 mmol/L).
Macadamias for 8 weeks did not change weight or body fat
In this randomized crossover trial, 35 overweight or obese adults with abdominal obesity took part. They ate macadamias for about 15% of their daily calories, on top of their usual diet. Total cholesterol fell 2.1% and LDL 4%, but both drops could have been chance, and blood sugar measures did not change. The study was funded by Hort Innovation of Australia.
Palmitoleic acid, a macadamia fat, raised LDL much like a saturated fat
In this randomized crossover trial, 34 men with high cholesterol took each of three test fats as supplements for 3 weeks. LDL and total cholesterol were similar with palmitoleic and palmitic (saturated) acid, and higher than with oleic acid. HDL was lower with palmitoleic than with palmitic acid. This tested the fat on its own, not macadamia nuts, which lowered LDL in several trials of the whole nut.
Macadamias lowered LDL cholesterol by 5.3% in men with high cholesterol
Seventeen men with high cholesterol (average age 54) ate 40 to 90 g of macadamias a day for 4 weeks, about 15% of their energy. Blood was tested before and after. Total cholesterol fell 3.0% and HDL rose 7.9%, while triglycerides did not change. The abstract describes no control group, so other causes cannot be ruled out.
Four weeks of macadamias lowered inflammation and oxidative stress markers
This second report from the same research group again had 17 men with high cholesterol eating 40 to 90 g a day for 4 weeks. Leukotriene B4 fell from 1,353 to 1,030 pg/mL and 8-isoprostane from 876 to 679 pg/mL. A blood-clotting ratio fell 23.6%, but this could have been chance. The abstract describes no control group.
A macadamia snack did not steady blood sugar after lunch; chicken did
In this randomized crossover trial, 17 healthy women ate a 70-calorie snack of macadamias, apple or chicken breast at 10:30 or 12:30. They wore a glucose monitor. Macadamias eaten mid-morning raised insulin resistance after lunch compared with no snack. The women ate the most at dinner after a mid-morning macadamia or apple snack. It was a small study of single snacks.
Macadamias lowered total and LDL cholesterol and body weight in young women
This short report compared 3-week diets of macadamia nuts, coconut and butter in healthy young Japanese female students. Total and LDL cholesterol also fell with coconut, and butter changed nothing clearly. Weight and body mass index fell only with macadamias. The abstract gives no group sizes or amounts, so it is hard to judge.
More nuts went with lower risk of coronary heart disease and death
This meta-analysis pooled 20 prospective studies of nut intake in adults. Each extra 28 g of nuts a day was linked to 0.71 times the risk of coronary heart disease. It was also linked to 0.78 times the risk of dying. Cardiovascular disease had 0.79 times the risk and total cancer 0.85, while stroke (0.93) was not clearly lower. Results were similar for tree nuts and peanuts. The abstract does not name macadamias, and a link is not proof of cause.
Macadamia oil reduced fat-cell enlargement and inflammation in obese mice
This study was in mice, not people, and it tested the oil, not whole nuts. Mice on a high-fat diet got macadamia oil by gavage (a feeding tube) for 12 weeks. The dose was 2 g per kg of body weight, three times a week. The oil lessened fat-cell enlargement and inflammation in fat tissue and in immune cells called macrophages.
Macadamia oil lowered blood fats in liver cells and fat-fed mice
This lab study used fat-loaded human liver cells and mice on a high-fat diet, with macadamia oil, not whole nuts. In the cells, 1000 µg/mL of the oil had effects comparable to 4.19 µg/mL of simvastatin, a cholesterol drug. In mice it lowered serum and liver cholesterol, triglycerides and LDL, and raised HDL. The authors link this to activation of the AMPK enzyme.
Lab test: short-chain fatty acids rose with particle size, not nut type
This lab study fermented almond and macadamia particles for 48 hours with bacteria from pig feces, so it was not a human study. Particles were fine (250 to 500 µm, micrometers) or in cell clusters (710 to 1000 µm). Macadamias favored three bacterial genera that almonds did not: Prevotellaceae UCG004, Candidatus Methanomethylophilus and Alistipes. Bacteria attached to the nut particles while their fat content fell.
Who should be careful with macadamia nuts
Most people can eat macadamia nuts freely. Take a little care if one of these applies:
- Tree nut allergy. The FDA lists macadamia among the tree nuts that must be named on labels, and reactions can be severe. In a study of 21 children with macadamia allergy, 8 had anaphylaxis (a severe, whole-body reaction). In 7 Spanish patients, hazelnut extract blocked IgE binding to a macadamia protein, a sign of cross-reactivity. If you react to other tree nuts, ask an allergist before trying macadamias.
- Dogs. Macadamias are toxic to dogs. The ASPCA lists weakness, vomiting and tremors, usually within 12 hours, with recovery expected in 24 to 72 hours. If a dog eats some, call a vet or the ASPCA Poison Control line at (888) 426-4435.
How to choose, store and eat macadamia nuts
- Raw: the nutrition facts on this page are for raw macadamias, 204 calories and 21.5 g of fat in a 1-ounce (28 g) serving.
- A daily handful, as a swap: the cholesterol trials used 42.5 g (1.5 ounces) and 40 to 90 g a day. The FDA claim names 1.5 ounces in place of saturated fat. In an 8-week trial, macadamias at about 15% of daily calories did not change weight.
- In the shell: the shell needs about 2,000 newtons of force to crack, so opening them at home takes real force.
Keep opened macadamias in an airtight container in a cool, dry place such as the fridge. Australian Macadamias says cracked kernels keep there for a few months, and longer in the freezer.
Sources
- Macadamia nut. ASPCA Animal Poison Control.
- People foods to avoid feeding your pets. ASPCA.
- Cortinovis C, Caloni F. Household food items toxic to dogs and cats. Front Vet Sci. 2016.
- Questions and answers regarding food allergens, including the food allergen labeling requirements of the Federal Food, Drug, and Cosmetic Act (Edition 5). U.S. Food and Drug Administration.
- Kubota K, Nagakura KI, Itonaga T, et al. Macadamia nut-specific IgE levels for predicting anaphylaxis. Pediatr Allergy Immunol. 2022.
- Gutiérrez-Díaz G, Betancor D, Parrón-Ballesteros J, et al. Identification of new allergens in macadamia nut and cross-reactivity with other tree nuts in a Spanish cohort. Nutrients. 2024.
- FDA completes review of qualified health claim petition for macadamia nuts and the risk of coronary heart disease. U.S. Food and Drug Administration.
- 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.
- Garg ML, Blake RJ, Wills RB. Macadamia nut consumption lowers plasma total and LDL cholesterol levels in hypercholesterolemic men. J Nutr. 2003.
- Jones JL, Sabaté J, Heskey C, Oda K, Miles F, Rajaram S. Macadamia nut effects on cardiometabolic risk factors: a randomised trial. J Nutr Sci. 2023.
- Macadamia. Wikipedia.
- How to crack and store macadamias. Australian Macadamias.
History of macadamia nuts
Macadamias are native to eastern Australia. The first European recorded as meeting the plant was the botanist Allan Cunningham in 1828. In the 1860s, an Aboriginal elder of the Logan River clan, known as King Jacky, traded the nuts with settlers.
In 1857 the botanist Ferdinand von Mueller named the genus Macadamia after his friend John Macadam, a scientist and secretary of the Philosophical Institute. A year later Walter Hill, who ran the Brisbane Botanic Gardens, recorded a boy eating the kernel. The boy was the first non-Indigenous person known to do so.
The first commercial orchard was planted near Lismore, New South Wales, in the 1880s. In 1882 William Purvis took macadamias to Hawaii, where they first served as a windbreak for sugar cane. A 2022 genetic study traced the Hawaiian cultivars back to Mount Bauple in southeast Queensland. Its authors call macadamia a recently domesticated crop.
Hawaii turned the nut into an industry. Ernest van Tassel formed the Hawaiian Macadamia Nut Company in 1922 and opened a processing factory in 1931. Grafting was first reported to work in 1937, which made mass production possible. In 1953 the Royal Hawaiian brand began to popularize the nuts in the United States.
Australia passed the United States as a major producer in 1997. South Africa overtook Australia between about 2012 and 2015 and has led since.
In 2014, a dispute over how macadamias were served on a Korean Air flight became known as the nut rage incident. It drew attention to the nut in South Korea, and consumption there rose sharply.
Sources
- Macadamia. Wikipedia.
- Lin J, Zhang W, Zhang X, et al. Signatures of selection in recently domesticated macadamia. Nat Commun. 2022.
- Nock CJ, Baten A, Mauleon R, et al. Chromosome-scale assembly and annotation of the macadamia genome (Macadamia integrifolia HAES 741). G3 (Bethesda). 2020.
Frequently asked questions about macadamia nuts
Are macadamia nuts good for you?
For most people, yes, in small amounts. A 1-ounce (28 g) serving has 204 calories and 2.4 g of fiber. It gives 51% of the Daily Value for manganese and 28% for vitamin B1.
Across 61 trials, tree nuts as a group lowered LDL cholesterol by 4.8 mg/dL per daily ounce. But macadamias alone have few small trials, and one 8-week trial found no clear change. They are calorie-dense, so portion size matters.
Do macadamia nuts lower cholesterol?
In small trials, yes. A diet with 42.5 g a day for 5 weeks lowered LDL from 3.44 to 3.14 mmol/L against an average American diet. A 30-day macadamia diet lowered it to 3.22 from 3.37.
A longer trial in adults with abdominal obesity found drops of about 4% that could have been chance. The authors of the 5-week trial point to swapping macadamias for foods high in saturated fat.
How many macadamia nuts should you eat a day?
No official amount is set for macadamias. The FDA claim names 1.5 ounces a day, and the cholesterol trials used 42.5 g and 40 to 90 g. At 204 calories an ounce, 1.5 ounces is about 300 calories, so it works best as a swap for other foods, not an extra.
Are macadamia nuts good for weight loss?
No trial here shows that they cause weight loss. In an 8-week trial of 35 adults with abdominal obesity, macadamias did not change weight, waist or body fat. They made up about 15% of daily calories.
A short Japanese study reported lower weight in young women, but its abstract gives no numbers. Each ounce has 204 calories, 91% of them from fat.
Are macadamia nuts toxic to dogs?
Yes. The ASPCA lists macadamia nuts as toxic to dogs, with weakness, vomiting and tremors, usually within 12 hours. Recovery is expected in 24 to 72 hours.
Its pages give no safe amount and list the toxic substance as unknown. So call a vet or ASPCA Poison Control at (888) 426-4435 if a dog eats any.
Are macadamia nuts keto-friendly?
They are low in carbs: 5.2 g of net carbs per 100 g, or 1.5 g in an ounce. Fat gives 91% of the calories. No study here tested a keto diet, and the calories are high at 204 an ounce, so portions still count.
Are macadamia nuts high in protein?
No. They have 7.9 g of protein per 100 g, or 2.2 g in an ounce, about 4% of their calories. That is less than pecans (9.2 g), walnuts (15.2 g) or almonds (21.2 g) per 100 g. So treat macadamias as a source of fat, not protein.