Given the recent blog-o-drama about carbs in the human diet (for instance, here and here), this seems like a fine time to blog about a sweet subject dear to my heart: fruit! More specifically, I want to take a closer look at some common beliefs about wild fruit, and how it differs from the store-bought stuff most of us have access to.
For those looking at evolution for clues about the optimal human diet, fruit is often regarded with suspicion. On one hand, few foods are “intended” for consumption in the way fruit is: In a lovely act of symbiosis, plants offer nourishment to the animal kingdom in trade for seed dispersal. But on the other hand—the one purpled with blackberry stains—we humans are famous for playing Food God, turning once-healthy things into gross abominations. For hundreds (and in some cases, thousands) of years, we’ve been selectively breeding certain fruits to become bigger, prettier, easier to eat, and easier to transport thousands of miles away from their mothering trees. As a result, the waxed apples and seedless watermelons lining store aisles are a far cry from their wild ancestors.
And for the health minded, this is a predicament. How can we reconcile this year-round supply of modern fruit with the wild stuff we encountered in the past?
Especially in the paleo/ancestral diet communities, statements like these tend to be widely accepted in a common sense, no-reference-needed sort of way:
- “Fruits in the Paleolithic would have been tart and smaller, and you may want to limit modern fruit because of this.” (From here)
- “The problem is that the fruits our paleo ancestors ate no longer exist. While they had mostly bitter fruit, we’ve bred ours over the past 200 years to be extremely sweet and sugary. It’s thus become something akin to candy plus a mediocre multivitamin.” (From here)
- “Bear in mind that the fruits that paleolithic man ate, while still being, say, apples, bore almost no resemblance to today’s apples. Modern fruit is bred to be HUGE and sweet. Most fruits are packed with a particularly bad sugar, fructose…”(From here)
- “Fruits have been selectively bread to contain massive amounts of sugar compared to how they used to be. Eating a bunch of tropical fruit is not in the spirit of Paleo.” (From here)
At first glance, that all seems logical enough. Virtually all the food we have available today—from plant and animal kingdoms alike—has been selectively bred for both flavor and ease of eating, and fruit is certainly no exception. It seems reasonable to conclude that, apart from the rare batch of honey or seasonal berry bushes popping up outside, humans didn’t get much exposure to sugar during our evolution, and modern fruits are completely unlike anything we encountered in the past.
But are these assumptions truly accurate? Let’s take a look at the facts.
(Note: This isn’t a post about how much fruit we should or shouldn’t be eating, or how much fruit we’ve eaten in the past, or how many apples it’ll take to turn your liver into a ready-to-explode fructose grenade. Those are some hot issues, and I’m not sure they can be reasonably addressed with current research (for instance, there are virtually no studies on the effects of fruit-derived fructose in healthy humans, and quantifying historical fruit consumption is extremely difficult). My intent here is to shed light on some of the myths surrounding wild and ancestral fruit, since some of the most common beliefs are also the most inaccurate.)
Wild fruit: small, bitter, and low in sugar?
Contrary to popular belief, wild fruit—including the stuff we would’ve had access to during our evolution—is not necessarily any of the above. In fact, it can be bigger, tastier, and sweeter than anything you’ll ever find in the aisles of your grocery store.
Fruit is decidedly sparser once you get out of the tropics, but considering we were stationed in Africa until about 50,000 years ago, the flora of a backyard in Michigan might not be a great reflection of the plant life we encountered for the majority of our evolution. As a result, comparisons of cold-climate fruits to their wild ancestors (for instance, a Red Delicious versus a crab apple) tend to be misleading, and tropical fruits may offer more insight. Although we’ll probably never get a clear picture of the exact fruits available to early humans, we can look at the wild fruits growing today to get an idea of what nature is capable of producing on its own.
There’s a great book called “Lost Crops of Africa” (readable online) that has a brilliant section on wild fruit. The authors start by describing the vastness of Africa’s wild fruit supply:
Most of Africa’s edible native fruits are wild. One compilation lists over 1000 different species from 85 botanical families and even that assessment is probably incomplete. Among all those fruit-bearing plants, many of the individual specimens growing within Africa are sheltered and protected, some are even carefully tended, but few have been selected to bring out their best qualities, let alone deliberately cultivated or maintained through generations. They remain untamed. … Africa’s wild-fruit wealth is essentially unknown to science.
So what kinds of “wild fruits” are we talking about here? Let’s take a look at some.
Nope, that’s not a cross between brains and canned peaches: It’s a monkey orange, a wild species native to Africa. Far from small, these fruits can weigh up to 2.5 pounds each—but untouched by the sweet-seeking hands of humans, is their flavor bitter and unpalatable? Quite the opposite:
In organoleptic taste tests, people were requested to compare the monkey orange fruit with familiar fruits; the most common answers were, orange, banana, and apricot, and all possible combinations among them. The fruits emit a delicate aroma reminiscent of the spice clove. … Over 90% of the panel claimed that it was very tasty.
Nom nom nom. Moving on:
Next up, we have the truly wondrous junglesop—a wild member of the same “sop” family that gives us cherimoyas, soursops, sweetsops, sugar apples, and other uber-sweet delicacies common in the tropics. If any uncultivated fruit can blast the “wild fruit is tiny” myth, it’s this sucker: Junglesops average 15 inches in length and weigh around 12 pounds each, with some of the larger fruits clocking in at 30 pounds or more. (Yes, these fruits are even heavier than your obese cat.) And folks lucky enough to live in the junglesop’s native regions seem quite fond of it:
It is so well liked in the regions where it occurs, that for example, in the Central African Republic, some people pay up more than one day’s salary for a single large fruit. A fruit of this size is several meals worth of food. In addition to being an important and widely liked fruit in equatorial Africa, it is also a very important staple for wildlife, especially primates.
Indeed, part of the reason the junglesop hasn’t been messed with by humans is because it does so darn well growing on its own. These fruits pop up like weeds in their homeland (West and Central Africa), and reach their enormous size without any human intervention. Looks like we should give nature more credit for making megafruits without our help.
Other wild fruits in this family are equally scrumptious:
One, the African custard apple, has been called “the best indigenous fruit in most parts of tropical Africa.” Another, the junglesop, produces probably the biggest fruits in the whole family—as long as a person’s forearm and as thick as a person’s thigh. A third—perhaps the strangest of all—“hangs like a bunch of sausages,” each fruit a bright scarlet link. At least two more produce small tasty fruits that make people’s mouths water at just the remembrance from a long-ago childhood. And this group includes a tangy fruit borne on a plant so strange that it barely rises above ground level.
You get the picture. And here are some more:
The soursop is an often-gigantic fruit of the Annona family that grows wild, but is now being increasingly cultivated in the tropics due to its awesome flavor. I’ve had the pleasure of trying these monsters in Hawaii, and they taste vaguely like the sour-apple gummy snacks I devoured in my youth. (I’ve also heard them described as a mixture of strawberry and pineapple.) The inside is moist, creamy white, and full of seeds. One of the few wild fruits with a documented nutrition profile, they’re decidedly high in sugar (30 grams per 150-calorie serving).
This fruit is as delicious as it is beautiful. The canistel—also called an “egg fruit”—is rich and dense, tasting like a cross between pumpkin pie and sweet potato. The name comes from its texture, which is a bit crumbly and resembles cooked egg yolk. Although bigger, prettier strains are being grown commercially these days (after being introduced to other parts of the world in the mid 1920s), the canistel still grows wild in Mexico, Belize, Guatemala, and El Salvador, where it retains its distinctive flavor. With 37 grams of sugar per 100-gram portion, this is another fruit that’s naturally sweet without human help.
Those are masukus, another wild fruit renowned for their sweet, delicious flavor. They might not be as visually pleasant as the store-bought fruit we’re used to seeing, but they’re highly sought after throughout Africa due to their taste.
Gingerbread plums are a wild African fruit with sweet, crunchy flesh reminiscent of strawberries. They’re considered one of the yummiest wild foods in Malawi. When they’re in season, many communities rely on gingerbread plums as a dietary staple, according to “Lost Crops of Africa.”
A distant relative of jackfruit (a giant that tastes like Juicyfruit gum), pedalai is a softball-sized wild fruit from Southeast Asia with soft, sweet white pegs of flesh inside.
Contrary to what it may seem, this wacky looking tree isn’t sprouting purple marbles: It’s a jaboticaba, AKA a Brazilian grape tree. This plant produces sweet, big, grape-flavored fruits that grow directly on the trunk—an evolutionary maneuver allowing non-climbing creatures to pick the fruits and disperse the seeds.
And this is a bacupari—a wild-growing fruit native to South America, with a very sweet, slightly acidic flavor.
Abiu, the Amazon-native wild fruit pictured above, is said to be pretty tasty: Their “delicious flavour is reminiscent of crème caramel and it is sometimes used to flavour ice cream and make other desserts,” according to Daleys Fruit Nursery.
So there you have it: just a small sampling of the many wild fruits that can be sweet, flavorful, and (sometimes) doggone big without us humans breeding them for centuries. Interestingly, one reason wild fruits have a reputation for being more sour than cultivated kinds isn’t because they have less sugar, but because they have more vitamin C, which imparts an acidic flavor. According to a paper about wild fruits in South Africa that I’ll be discussing in the next section:
The composition of these [wild] fruits does not appear to differ much from the better-known domestic fruits except in so far as their vitamin C content is substantially higher than that of domestic fruits. The high vitamin-C content of the wild fruits must undoubtedly contribute to their characteristic acidity.
Nutrient profile of wild fruit
A common belief about wild fruit is that it’s generally lower in sugar and digestible carbohydrates than our modern varieties. Although most of the world’s wild fruits are relatively unstudied (making it difficult to analyze this claim), we do have information on some of ’em. For instance, a paper published decades ago in the South African Journal of Nutrition, called “The nutrient composition of some edible wild fruits found in the Tansvaal” (PDF), documents the nutrient breakdowns of some of southern Africa’s most popular wild fruits. Here’s a table from the paper:
Wondering why the protein, fat, and carbohydrate percentages look so funny and don’t add up to 100? These measurements are based on dry weight rather than caloric yield like we’re used to seeing—so those are just the relative weights of each macronutrient, with moisture and ash (basically a measurement of mineral content) making up the rest. You can still get a sense of which macronutrient dominates in each type of fruit by looking at that chart, but to make it easier, I went ahead and converted those numbers into “percent of total calories” for all the fruits and graphed ’em. This is using only non-fiber carbohydrate so we don’t inflate these figures with indigestible carbs (we’ll cover fiber a bit further down). The first monkey orange values are for the flesh surrounding the seeds; the second values are for the flesh on the inside of the shell.
These puppies range from 78 to 92% of calories from carbohydrates. How does that measure up with some of the fruits more likely to find their way onto our kitchen counters? Let’s compare:
Pretty consistent, right? The biggest difference is that some wild fruits are a bit higher in protein than cultivated varieties, but in general, the macronutrient breakdowns are pretty similar. With the exception of durian (and avocado, which I didn’t graph), cultivated fruits—including berries—tend to hover around 85 to 95% of calories from carbohydrate. (Unfortunately, the data set for wild fruit doesn’t tell us how much of the carbohydrate content was from sugar versus starch, so this comparison is still incomplete.)
It’s quite possible that the macronutrient breakdown of wild fruits is more diverse than indicated by the sample above, but studies from other geographical locations offer similar data. For instance, a paper on Australian Aboriginal plant foods found that indigenous fruits had a similar or higher carbohydrate content compared to domestic fruits.
So what about the claim that wild fruits are much higher in fiber than cultivated varieties? Going back to the data set above, let’s look at the ratio between fiber and total carbohydrate in various fruits. These ratios can be read as “1 part fiber for every X parts total carbohydrate”—so the lower the second number, the greater the relative fiber content of that fruit.
Fiber:total carbohydrate ratio in wild fruits
- Wild plum: 1:6
- Marula fruit: 1:15
- Wild apricot: 1:42
- Monkey orange, flesh around seeds: 1:4
- Monkey orange, flesh around shell: 1:4
- Amatungulu: 1:11
- Baobab: 1:10
- Sour plum: 1:17
- Red gherkin: 1:11
Fiber:total carbohydrate ratio in cultivated fruits
- Papaya: 1:6
- Guava: 1:3
- Strawberries: 1:4
- Cantaloupe: 1:10
- Oranges, Valencia: 1:5
- Apricots: 1:6
- Grapefruit: 1:7
- Pear: 1:5
- Banana: 1:9
- Grapes, American: 1:20
- Nectarines: 1:6
- Peaches: 1:7
- Blueberries: 1:6
- Honeydew melons: 1:12
Basically, we have quite a bit of fiber variation among both wild and cultivated species. Of the wild fruits listed in the paper above, the fiber-to-total-carb ratio ranges from 1:4 for monkey oranges to a whopping 1:42 for wild apricots (meaning the monkey orange has a decent amount of fiber, while the wild apricot has relatively little). Similarly, the sampling of cultivated fruits here range from 1:3 for guava to 1:20 for American grapes. At least from this data, it seems that wild fruit isn’t universally higher in fiber than cultivated varieties, at least not when we look at the edible portion of the fruit.
The fructose factor
If you’ve been keeping up with the latest health news, you’ve probably noticed fructose stealing the spotlight as a potential factor in obesity, non-alcoholic fatty liver, metabolic syndrome, and other health woes (for instance, see Robert Lustig’s “Sugar: The Bitter Truth“). Although most of the finger-pointing has been at high-fructose corn syrup and other refined sweeteners, fruit has also taken a whooping because of its natural fructose content. Modern fruit, in particular, has been accused of being higher in fructose than ancestral and wild strains and thus less healthy than it was in the days of yore. In my frequent internet lurks, I often see unreferenced advice to limit fruit consumption to berries, which are supposedly lower in fructose than other varieties of fruit.
But is there truly a significant difference in fructose between wild and cultivated fruits?
Once again, wild fruits are terribly understudied in terms of nutrients (especially sugar composition), but we do have a few resources out there to mine for clues. One is the paper “Phytochemicals, vitamin C and sugar content of Thai wild fruits” published in Food Chemistry in 2011. This article has a nice breakdown of the sugars in 19 wild fruits from Southeast Asia. I’ve graphed them out below.* If you’re not a botany buff, don’t worry about the gibberish-esque Latin names: Just look at the pie charts to get a visual feel for what sugars are abundant in some wild species.
*For the fruits that had a listing for both “ripe” and “raw” (not ripe), I only graphed the “ripe” data.
(Note: Maltose and galactose made up a minor portion of the sugars in some of these fruits, but for the sake of keeping things simple, I’m only graphing the three major sugars—sucrose, glucose, and fructose. And since sucrose cleaves into equal parts fructose and glucose in your body, all the blue pie slices below could be viewed as contributing half fructose and half glucose.)
If there’s any pattern here, it’s that most of these fruits are comprised of at least half glucose and a hefty dose of fructose—but three are actually sucrose-dominated, so there aren’t any set-in-stone rules regarding sugar distribution in wild fruits. Likewise, human-bred fruits are all across the board in terms of sugar. Berries (both wild and cultivated) tend to be about half fructose with only minimal amounts of sucrose, while other commercial fruits contain more sucrose and proportionately less fructose and glucose. Take a look at some common varieties as an example:
Whether you’re looking at straight-up fructose or fructose derived metabolically from sucrose, there’s really no basis for the claim that wild fruit is lower in fructose than cultivated varieties—at least in terms of sugar breakdown. After digestion, both wild and cultivated fruits seem to yield about 50% fructose.
Although many wild fruits do have a limited harvesting period, this doesn’t mean early humans would only have access to fruit for only a few weeks or months per year (as is sometimes stated). Particularly in tropical climates, different plant species tend to bear fruit at different times annually—and even plants of the same genus or species can have staggered fruiting periods within the same region. Although a single fruit might not have been available year-round, different species would certainly provide access to fruit beyond a single season.
On top of that, some species remain edible for months after they ripen, and others naturally sun-dry on the plant, making them easy to store for later consumption. For example:
- The monkey orange, mentioned earlier: “These three special monkey orange trees are widely enjoyed and have the amazing capacity to stay edible in tropical heat for months after maturity.”
- Sand apples can be easily dried and formed into a long-lasting “cake.”
- Australian aborigines dry a number of desert fruits to eat throughout the year, including the raisins Solanurn centrale and S. ellipticurn and the bush tomato.
On the flip side
Despite all of the above, there are some notable differences between wild fruits and cultivated ones:
- The ratio of pulp vs. inedible stuff. Wild fruits tend to have thicker peels and bigger seeds, strings, rinds, cores, and other gnarly bits relative to the amount of edible flesh they yield. Even when sugar composition doesn’t differ dramatically between the edible parts of wild versus cultivated species, a single wild fruit will generally provide a lot less edible material than a cultivated fruit of the same size. This is one area where humans have definitely left our signature in fruit breeding: We like our cultivated fruits to be seedless (or at least low in ’em), easy to bite into, easy to peel, and abundant in edible flesh. Due to their extra roughage (and sometimes-scary exteriors), wild fruits can be more of a challenge to eat. (This doesn’t just apply to sweet fruits, either: See my earlier post on wild avocados.)
- Water content. Interestingly, wild fruits are often calorically denser than cultivated fruits due to their lower water content. Whereas humans seem fond of fruits with a juice-dribbling-down-your-chin effect, wild fruits are sometimes (but not always) dry, crumbly, crunchy, mushy, and otherwise non-juicy. The higher water content of cultivated fruits makes them appear relatively lower in protein and fat than wild varieties (as primate-diet-expert Katharine Milton points out in many of her publications), even though this isn’t usually the case when viewed from a calorie perspective.
- Fruiting cycles. On an individual-species basis, the fruiting cycles of wild versus cultivated fruit tend to be very different. In the wild, plants can have variable fruiting periods depending on climate, season, rainfall, and even the specific year (some plants are biennial, bearing most of their fruit once every two years), leading to inconsistent fruit yields. Farmers, on the other hand, may deliberately control or extend fruiting periods so that a particular fruit stays in season longer or hits the grocery store shelves earlier than nature dictates.
- Dangerous natural substances. Although most cultivated fruit is pretty safe from a toxicity perspective, wild fruits—especially under-ripe ones—can contain an array of natural toxins causing everything from an upset stomach to death. Alkaloids, tannins, cyanogenic glycoside (which turns into cyanide), and a variety of other compounds can exist in some types of wild fruit, making it imperative to know which parts are safe to eat. These substances can also make some types of wild fruit difficult to eat in large quantities without feeling queasy.
- Flavor variability. Because flavor is influenced by soil quality (among other things), wild fruits of a single species can sometimes vary tremendously in taste. The junglesop, for instance, can span a wide range of flavors—not all of them pleasant. According to Lost Crops of Africa: “In some varieties [the junglesop flesh] is deliciously sweet and very good to the taste; in others, it can be not only sour but downright awful. Just how mature the fruit was when picked can affect the sweetness, but genetics also plays a part, and locals know individual trees that are always sweet and others that are always sour.”
- Micronutrients. Some wild fruits are far more nutritious than the conventionally-grown ones we throw into our shopping carts, although the vitamin and mineral content of wild fruit fluctuates almost as much as flavor. I initially planned to write a separate section on this subject, but the papers I found were so inconsistent (some showing high levels of certain micronutrients in wild fruits, others showing low levels compared to cultivated fruit) that it seems impossible to say anything definitive.
In addition, if you rounded up every single wild fruit species in the world (not just ones preferred by primates with somewhat-similar digestive anatomy to ours), the majority likely would be small and unpalatable. Wild sweet fruits are a favored minority. This isn’t necessarily a blow against fruit, though. You could also argue that if you rounded up every animal, every vegetable, or every seed in the world, the majority would be small and unpalatable. Across the board, humans have distinct preferences within each food category, such a for sweeter fruit, fattier meat, and less-bitter vegetables.
If you’re in brain-burnout mode and didn’t absorb all that (I can empathize!), here’s the Reader’s Digest version of this post.
- Although not all wild fruits are as big and sweet as our modern cultivars, at least some are, and certain varieties even surpass our deliberately-bred fruits in size and flavor. Nature—especially with selection pressure from other fruit-eating creatures—is perfectly capable of producing sweet (and sometimes massive) fruits without human intervention. It seems unlikely that early humans only ever encountered berries or other “small, bitter” fruits, and avoiding sweeter fruits on the basis of evolutionary history may be misguided.
- Based on the limited research we have, wild fruits aren’t considerably different from cultivated fruit in terms of carbohydrate content, fructose content, or fiber content. Both wild and cultivated fruit seem to average around 90% of calories from carbohydrates, and have a sugar composition that yields roughly equal parts glucose and fructose. And both wild and cultivated fruit can be relatively high or low in fiber.
- Although berries are often lauded as being lower in fructose compared to other fruits, from a calorie/energy standpoint, this just ain’t true!
- Early humans may very well have had access to fruit for most or even all of the year. The fruiting seasons we witness in cooler climates—with most fruit appearing in the summer—doesn’t necessarily apply to our evolutionary homeland closer to the equator.
I blame the “wild fruit is bitter and small” belief on our woeful state of food education. Most people can name more types of candy than they can of fruit, even though there are literally thousands of edible varieties across the globe—a great many of them wild. With the exception of raw foodists, well-traveled gourmands, and anyone who hangs out at Asian markets, most people’s concept of “fruit” is limited to the standard grocery store staples, with little idea of what else is out there.
Again, this post is only intended to be descriptive, not prescriptive. Fruit is a regular part of my own diet, but I also believe dietary context and individual health history plays a big role in how people react to nature’s proverbial candy. If you avoid modern fruit on the basis that only “small, bitter, fibrous” fruit was available in the past though, it might be time for a paradigm shift.