Olives and Coconut

TL;DR. Two fruits we mostly consume as fat, and the health evidence for them points in opposite directions. Olive oil, particularly extra virgin, is the single best-evidenced fat in the diet, with a large randomised trial (PREDIMED) behind it and a set of polyphenols that plain refined olive oil lacks. Coconut oil is 80 to 90 percent saturated fat, raises LDL cholesterol more than butter in controlled trials, and its health-food reputation rests on a medium-chain triglyceride argument that does not apply to it. A raw olive is inedible; every olive you have eaten was cured to remove a bitter compound.

1. What they are

Olive (Olea europaea, family Oleaceae, with ash, lilac, and jasmine) is a drupe, like a plum, with a single stone. The tree is evergreen, extraordinarily long-lived (trees of over a thousand years still fruit), and drought-tolerant.

Coconut (Cocos nucifera, family Arecaceae, the palms) is also botanically a drupe, not a nut, with three layers: the smooth outer skin (exocarp), the thick fibrous husk (mesocarp, which becomes coir), and the hard shell (endocarp) containing the seed. What we call the "meat" is the seed's endosperm, and coconut water is liquid endosperm.

The three "eyes" on a coconut shell are germination pores, one of which is soft and is where the shoot emerges. It is also the one you can push a skewer through.

2. Where they come from

Olive: the eastern Mediterranean and Levant, domesticated around 6,000 years ago. It is the defining crop of Mediterranean civilisation: olive oil was food, fuel for lamps, cosmetic, soap, and religious anointing, and its trade underpinned Minoan, Greek, and Roman economies. The Mediterranean basin still accounts for around 95 percent of world production.

Coconut: Southeast Asia and the western Pacific, with genetic evidence for two separate domestication events, in the Pacific and the Indian Ocean. Coconuts float and remain viable in seawater for months, which is why they colonised tropical coastlines worldwide with and without human help.

Production: olives around 20 to 23 million tonnes, with Spain producing roughly 40 percent of the world's olive oil (Andalusia alone is the largest olive-growing region on Earth), followed by Italy, Greece, Turkey, Tunisia, and Morocco. Coconuts around 60 million tonnes, led by Indonesia, the Philippines, India, Sri Lanka, and Brazil.

3. How they are grown

Olive. A Mediterranean-climate crop: hot dry summers, mild wet winters, and it needs a period of cool weather (roughly 200 to 300 chill hours below 10 °C) to flower. It is remarkably drought-tolerant and thrives on poor, stony, alkaline soil where little else grows, which is exactly why it dominates Mediterranean hillsides.

It is strongly alternate bearing, cropping heavily one year and lightly the next, and it is wind-pollinated, mostly self-incompatible, so groves interplant varieties. Trees begin bearing at 5 to 8 years and continue for centuries.

Three production systems now coexist and they are very different:

• Traditional: 80 to 150 widely spaced trees per hectare, often ancient, hand or shaker-harvested, low yield, high quality potential.
• Intensive: 200 to 500 trees per hectare, mechanised trunk shakers.
• Super-high-density (hedgerow): 1,200 to 2,000 trees per hectare on dwarfing varieties (Arbequina, Arbosana, Koroneiki), trained as a hedge and straddle-harvested by machine like a vineyard. This system has transformed the economics of olive oil, produces the majority of new plantings, and is one reason cheap olive oil exists.

Harvest timing decides everything about the oil. Green, early-harvested olives yield less oil, and that oil is higher in polyphenols, more bitter, more peppery, and more stable. Fully ripe black olives yield more oil that is milder and lower in polyphenols. Premium early-harvest oils are a genuinely different product, not just a marketing tier.

Oil is extracted mechanically, without heat or solvent, for extra virgin grades: the olives are crushed to a paste, malaxed (slowly mixed) to coalesce oil droplets, and then centrifuged. The whole process must be completed within hours of picking, because olives begin to ferment.

Xylella fastidiosa, a bacterium spread by sap-sucking insects, has killed millions of centuries-old olive trees in Puglia, southern Italy, since 2013, and there is no cure. It is the olive's equivalent of the citrus greening and banana Race 4 stories.

Coconut. A tropical coastal palm needing constant warmth (above 20 °C), high rainfall or a high water table, and tolerance of salt spray and sandy soil. Palms begin bearing at 5 to 8 years (dwarf varieties earlier), produce 50 to 200 nuts a year, and crop for 60 to 80 years. Nuts mature over about a year, and a palm carries fruit at every stage simultaneously, so harvest is continuous.

Harvesting means climbing a 20 to 30 metre palm, which is skilled, dangerous, and increasingly short of labour. In parts of Thailand and Indonesia, pig-tailed macaques are trained to pick coconuts, a practice that has drawn significant animal welfare criticism and led some retailers to delist Thai coconut products.

Lethal yellowing and related phytoplasma diseases have killed millions of palms across the Caribbean and West Africa.

4. What is inside them

Per 100 g:

The two critical numbers:

• Olive oil is 73 percent monounsaturated (oleic acid) and contains meaningful vitamin E and K, plus polyphenols in the extra virgin grades.
• Coconut oil is 87 percent saturated, mostly lauric acid (C12), which is the crux of the argument below.
• Cured olives are extremely salty. A handful of ten olives can supply 400 to 800 mg of sodium, a significant fraction of a day's limit.

Olive polyphenols are the reason extra virgin oil differs from refined. The key compounds are oleuropein, hydroxytyrosol, tyrosol, and oleocanthal. Oleocanthal is responsible for the peppery catch at the back of the throat from a good fresh oil, and Gary Beauchamp and colleagues showed in 2005 that it inhibits COX-1 and COX-2, the same enzymes ibuprofen inhibits, producing the same throat irritation ibuprofen solution does. The doses from normal consumption are far below a therapeutic ibuprofen dose, and the mechanistic parallel is real.

Refining olive oil (heat, solvent, deodorising) removes essentially all of these polyphenols, which is why refined "olive oil" and "light olive oil" are nutritionally much closer to a generic vegetable oil.

5. What they do in your body

Olive oil

The PREDIMED trial is the strongest single piece of evidence for any dietary fat. Over 7,000 people at high cardiovascular risk in Spain were randomised to a Mediterranean diet supplemented with extra virgin olive oil, the same diet supplemented with nuts, or a low-fat control diet. The trial was stopped early for benefit. After reanalysis to correct randomisation irregularities at some sites, the published 2018 New England Journal of Medicine result stands: roughly a 30 percent reduction in major cardiovascular events in the olive oil group compared with control.

That is a randomised, hard-endpoint, primary-prevention result, which is rare in nutrition. Caveats apply (the control group was not adherent to a genuinely low-fat diet, and the intervention was a whole dietary pattern rather than oil alone) and it remains the best evidence in the field.

Subsequent cohort work is consistent: higher olive oil intake is associated with lower cardiovascular and total mortality, with the association apparent from roughly half a tablespoon a day upward.

Mechanistically: oleic acid replacing saturated fat lowers LDL; polyphenols improve endothelial function, reduce LDL oxidation, and have anti-inflammatory effects. The EU has authorised a health claim that olive oil polyphenols protect blood lipids from oxidative stress, at 5 mg of hydroxytyrosol and derivatives per 20 g of oil.

Coconut oil

The health-food case for coconut oil rests on medium-chain triglycerides, which are absorbed directly into portal blood, go straight to the liver, and are rapidly oxidised rather than stored. That is a real property of MCTs.

The problem is that coconut oil is not primarily an MCT oil in the relevant sense. About 47 percent of it is lauric acid (C12), and lauric acid behaves metabolically much more like a long-chain fat: it is largely packaged into chylomicrons and transported through the lymph, not the portal vein. Commercial MCT oil, used in the research showing metabolic effects, is purified C8 and C10, which coconut oil contains at only about 13 percent.

What controlled trials show. A 2020 meta-analysis in Circulation by Neelakantan and colleagues, covering 16 trials, found coconut oil raised LDL cholesterol by roughly 0.4 mmol/L (about 15 mg/dL) compared with non-tropical vegetable oils, an effect comparable to or greater than butter. It also raised HDL. No trial has shown improved cardiovascular outcomes.

The American Heart Association's 2017 advisory recommended against coconut oil for this reason. A widely quoted 2018 remark by a Harvard epidemiologist calling it "pure poison" was hyperbole that generated more heat than clarity; the accurate statement is that it is a saturated fat with no demonstrated advantage over unsaturated alternatives, and that using it as a flavouring is fine while using it as a health measure is not supported.

Coconut water is genuinely useful as a rehydration drink: naturally around 250 mg of potassium and 105 mg of sodium per 100 mL, low in sugar compared with sports drinks. It has been used as an emergency intravenous fluid in extreme circumstances, which is a real historical footnote and not a recommendation. It is not superior to water for ordinary hydration, and it is a poor sodium replacer for heavy sweat losses because sodium is what you mostly lose.

6. What the evidence actually shows

Established: extra virgin olive oil polyphenols protect LDL from oxidation (an authorised EU health claim). Coconut oil raises LDL cholesterol relative to unsaturated oils.

Strong: olive oil, within a Mediterranean dietary pattern, reduces cardiovascular events (PREDIMED, randomised). Higher olive oil intake is associated with lower mortality across multiple cohorts.

Mixed: olive oil polyphenols for cognition, cancer, and inflammation, where evidence is mechanistic and observational. Coconut oil and MCTs for cognition in Alzheimer's disease, an area of genuine research interest with weak clinical results so far.

Thin to refuted: coconut oil for weight loss, for "boosting metabolism," or for heart health. Oil pulling (swishing coconut or sesame oil in the mouth) for detoxification or systemic disease is unsupported; there is limited evidence for a small effect on plaque and gingivitis, and it does not replace brushing.

7. Who should eat more, who should be careful

Good for: almost everyone, in the case of olive oil. It is one of the few foods in this book that a large randomised trial supports.

Be careful if:

• You are watching sodium. Cured olives are among the saltiest foods in the produce aisle. Rinsing removes some.
• You have high LDL cholesterol. Coconut oil is not the fat to cook with. Use olive oil, rapeseed, or high-oleic sunflower.
• You have a nut allergy. Coconut is botanically a drupe, not a tree nut, and most people with tree nut allergy tolerate it. However, the US FDA classifies coconut as a tree nut for labelling purposes, which causes real confusion. Coconut allergy exists and is rare. Discuss with your allergist rather than assuming either way.
• You have IBS. Coconut milk in large quantities is high-FODMAP (sorbitol); small servings are fine. Olives are low-FODMAP.
• You are buying "extra virgin" cheaply. Olive oil adulteration and mislabelling are well-documented, persistent, and occasionally criminal. Multiple studies and Italian prosecutions have found oils labelled extra virgin failing the chemical or sensory standard. Buy oils with a harvest date, a named region or estate, in dark glass or tin, and be suspicious of a price that is too low.

Ages. Olive oil from the start of weaning; it is a good fat source for infants. Whole olives and pieces of coconut are choking hazards for young children, and olives contain stones.

8. How olives are cured, and why

A raw olive is inedible, extraordinarily bitter, because of oleuropein, a phenolic glycoside. Every olive you have eaten has been processed to remove or convert it. The method changes the flavour completely.

That last row explains the tinned black olives most people first encounter: they are green olives, chemically blackened. Genuine tree-ripened black olives (Kalamata, Gaeta, Niçoise) are purple-black, wrinkled or plump, and taste nothing like them.

9. Choosing and storing

Olive oil.

• Buy dark glass or tin. Light degrades oil rapidly.
• Look for a harvest date, not just a best-before. Olive oil is at its best within about 12 to 18 months of harvest and degrades from there.
• Extra virgin means it meets both chemical standards (free acidity below 0.8 percent) and a sensory panel test with zero defects. Virgin is a lower tier. Plain "olive oil" or "pure olive oil" is refined oil with a little virgin blended back. Light refers to flavour, not calories.
• Store cool and dark, lid on, and use within a couple of months of opening.
• Taste it. Good extra virgin oil should smell green and taste bitter and peppery, with a cough-inducing catch at the back of the throat. Those are the polyphenols. Bland, greasy, or waxy oil is old or refined.
• You can cook with it. Its smoke point (190 to 210 °C) is adequate for almost all home cooking, and its oxidative stability is better than more polyunsaturated oils (Chapter 13).

Olives: loose from a deli beats jarred, and jarred beats tinned. Store in their brine, refrigerated once opened. Olives that have gone soft or smell of acetone have spoiled.

Coconut: a fresh coconut should feel heavy and slosh when shaken; no sloshing means it has dried out or leaked. The three eyes should be dry and free of mould. Refrigerate fresh meat and use within a few days. Desiccated coconut and coconut milk keep well; coconut oil is very oxidation-resistant because it is saturated, and keeps for years.

10. The varieties worth knowing

Olives: Picual (Spain, high polyphenol, very stable, the dominant oil variety), Arbequina (Spain, mild, buttery, the hedgerow variety), Koroneiki (Greece, intense, high-yield oil), Kalamata (Greece, the classic table olive, tree-ripened purple), Frantoio and Leccino (Tuscany), Manzanilla and Gordal (Spanish table olives), Nocellara del Belice/Castelvetrano (Sicily, bright green, buttery, mild), Niçoise/Taggiasca (small, dark, nutty).

Coconut: tall varieties (traditional, tall, long-lived, better copra) and dwarf varieties (early bearing, easier harvest, better for drinking nuts). Green drinking coconuts are immature fruit; brown ones are mature.

11. Myths and confusions

Don't be confused: coconut oil is not a medium-chain triglyceride oil in the way the research means. Nearly half of it is lauric acid, which behaves like a long-chain fat. The MCT research uses purified C8 and C10, which is a different product with a different label.

• "Extra virgin olive oil should not be heated." It is stable enough for normal cooking and more oxidation-resistant than most seed oils. Deep-frying in it is a cost decision.
• "Coconut oil is healthier than butter." Controlled trials find it raises LDL as much as or more than butter.
• "Coconut water is nature's sports drink." Good potassium, low sodium, less sugar than a sports drink. Fine, unremarkable, and not superior to water for most purposes.
• "Black olives are ripe olives." Most tinned black olives are green olives chemically blackened with ferrous gluconate.
• "MCT oil / coconut oil in coffee burns fat." It adds calories. There is no fat-burning mechanism.
• "Olive oil in the fridge should solidify if it is real." A widely circulated fake test. Different olive oils and adulterants solidify at different temperatures, and the test proves nothing.

12. The bottom line

• Extra virgin olive oil is the best-evidenced fat in the diet, with a randomised hard-endpoint trial behind it, and its polyphenols are the difference between it and refined olive oil. Buy oil with a harvest date, in dark glass, and expect it to taste bitter and peppery.
• Coconut oil is 87 percent saturated fat and raises LDL more than butter in controlled trials. The MCT argument for it does not apply, because its dominant fat is lauric acid. Use it for flavour, not for health.
• A raw olive is inedible. Curing is what makes it food, and the tinned uniformly black olive is a green olive chemically blackened.
• Cured olives are very high in sodium. Coconut water is a decent, unexceptional, low-sugar drink.

Sources and notes

Composition figures are from USDA FoodData Central; production figures are approximate FAOSTAT values for the early 2020s. Olive domestication and Mediterranean spread follow Kaniewski et al.'s palaeobotanical work. Super-high-density orchard systems and harvest timing effects on polyphenol content follow Spanish and Australian olive industry research. Oleocanthal's COX inhibition and ibuprofen-like throat irritation is Beauchamp et al., Nature, 2005. The EU health claim for olive oil polyphenols is EFSA's 2011 opinion, requiring 5 mg hydroxytyrosol per 20 g. PREDIMED is Estruch et al., New England Journal of Medicine, 2018 (the re-analysed publication). Olive oil intake and mortality follows Guasch-Ferre et al., Journal of the American College of Cardiology, 2022. Xylella fastidiosa in Puglia follows EFSA and Italian ministry reporting. Coconut oil and LDL is the meta-analysis by Neelakantan et al., Circulation, 2020, and the AHA 2017 presidential advisory. The lauric acid transport argument follows Sankararaman and Sferra's review. Olive curing methods and the ferrous gluconate blackening of Californian ripe olives follow food technology references. Olive oil adulteration follows Italian prosecutions and the UC Davis Olive Center testing reports. Oil pulling evidence follows dental systematic reviews.

Open questions. How much of PREDIMED's benefit is attributable to olive oil specifically rather than to the whole dietary pattern cannot be separated by that trial's design. Whether the polyphenol content of commercially available extra virgin oil reaches the levels used in mechanistic studies is often untested at point of sale.

👉 Next: superfruits, juice, and smoothies, where the marketing is thickest.