Of the nutrition questions I’m asked most often, “What do you think about very high fruit diets?” is near the top of the league.
To be clear, we’re not just talking here about eating “a lot” of fruit.
We’re talking about getting the majority of our calories from fruit, as recommended by certain popular raw diet gurus.
And the short answer is that I think this way of eating is a disaster for most people.
I say that based on:
- my own personal experience
- the experience of the majority of people I’ve spoken to who’ve tried it
- extensive reading on evolution and diet
- extensive reading on biochemistry
If I went into detail on all of the above this would be a very long article and I want to keep it short and sweet.
What to tell you?
Well…I’ll start with me.
When I first started to look into the concept of eating mostly fruit I fell head over heels in love with it.
I’m a sugar addict, so that was one reason.
But I’m also a sucker for simplicity, so when I was in my purest purist phase there was never a diet that more appealed to me; never one I more wanted to be “The One True Way” to dietary nirvana (back when I still thought such a thing existed).
I’d read (as you may have done) that the key to making it work is that you have to eat mega quantities of fruit.
So not one or two bananas for breakfast but 10. Not a slice of melon, but the whole melon.
It was larger than a football but you’re still hungry? Have another.
Well, I tried it and no matter how much fruit I ate, I was hungry again within an hour.
I could sit down to a watermelon the size of a bowling ball at 9am and by 10am I’d be hungry again.
So, I’d have another “fruit meal”. Maybe a big green smoothie made with three bananas, a cup of berries and the rest of the blender filled with foliage. That would satisfy me for about an hour thanks to the greens (whereas a pure fruit smoothie never would) but by 11 I’d be wanting to eat again.
Perhaps I’d then eat six peaches. All this would get me reliably bloated, but never sated.
I now realise that the term “fruit meal” is an oxymoron for those of us with a fast metabolism.
But I was so convinced this way was right that I let dogma guide me more than the feedback from my own body.
And my health, teeth, moods and energy levels suffered.
Most of us just do not have systems that are designed to run on fruit.
And why would we?
It is not our “natural” or “species-specific” diet, as some proponents of this diet claim.
It is the species-specific diet of a distant ancestor of humans.
Which means, and this is key, a different species altogether.
Not a human one but a pre-human one, with a markedly different digestive system, which lived over four million years ago.
Humans have colonised the whole of this planet and it is a scientific fact that our species has shown itself capable of thriving in any of its diverse environments, as long as we eat the foods in that environment, in their natural state.
A fruit-based diet is natural in only one of these environments, and one in which very few humans live: rainforest.
There is nothing natural about living in England, or New England, and eating meals of bananas and mangoes. This is true in July, and even truer in January.
But please don’t misunderstand me.
I’m not saying the high fruit diet is a disaster for everyone. I’ve met people who’ve been eating high fruit long term and are getting great results.
But, as stated in the heading of this article, high fruit diets are a disaster for most of us.
If you’re doing well on a high fruit diet but have been eating this way for only a few months or a year or two, then experience tells me you may run into problems down the line as you run down your reserves of the nutrients that are lacking on this diet, while running massive amounts of insulin through your system (more on that below).
And if you’re (a) following a very high fruit diet but not feeling well on it, or (b) considering trying this way of eating, please read on.
The first fact to be aware of is that those who thrive, or could do, on a very high fruit diet long term are in a minority.
And if you’re in that minority, chances are good that you (a) live in a warm climate (or at least spend a large portion of your year in one) and (b) exercise a lot.
I’ve never met anyone who does well on this diet who doesn’t have at least (a) or (b) in a big way.
But to be clear, most people I know who live in a warm climate and exercise a lot, and who have tried existing on mostly fruit, did not thrive on it even short term, let alone long.
Location and activity level matter because:
By definition, a natural diet must be one where we source our foods from the environment in which we live. A diet based on fruit air-freighed in from thousands of miles away has only been possible for a couple of decades.
Imported fruit is almost always picked unripe so is missing key minerals and other nutrients needed for its digestion. This makes it an acid-forming and demineralising food choice.
Fine as an occasional treat. Not advisable as the basis of a diet for months on end.
Unless fruit is both seasonal and local, the small amount of nutrition it brings is not worth the large amount of sugar you take in along with it.
I’ve heard from so many on high-fruit diets who are eating six or more large fruit meals a day in order to stick to the diet, or even who are eating fruit every waking hour. Some basically graze on it all day long and never feel satisfied.
Why? Because (a) they are riding the blood sugar roller coaster and (b) the fruit is not giving them the nutrients their body is crying out for.
Chances are you know that there are planetary health implications to eating this way as well as personal health ones.
I’ve never met anyone in England who is following a fruit-based diet who isn’t eating boxes and boxes of air-freighted fruit every week for at least six months of the year. Carbon footprint: colossal.
The sugar intake of a diet based on sweet fruits is also colossal and that is why exercise is essential.
Because, and this is key, any time you eat more sugar than your body can utilise, your pancreas releases insulin to regulate your blood sugar. And the more sugar you eat, the more insulin it releases.
What this means is that if you eat a whole melon in one go, several mangoes, a bunch of bananas or any other large quantity of sweet fruit, and have not exercised hard within the last 24 hours, that will cause an insulin spike, and that is not a good thing.
And if you’re eating like this three or more times a day, you need to be exercising hard for hours a day.
As veteran raw food expert Dr Fred Bisci told me in our 2010 intertview, “Any time you consume a lot of fruit and haven’t been exercising very heavily to use all the sugar you’re eating, you’ll be secreting a lot of insulin. If your blood sugar is in the normal range after eating a lot of fruit and you haven’t been exercising heavily, that is only possible because you’ve secreted a lot of insulin.
“If you’re eating a lot of fruit – and especially if you’re eating it all day – you’re definitely going to have a lot of insulin in your blood on a consistent basis and this is going to lead to problems. If you want to do this you need to be spending five to six hours a day working out, which I do not recommend.
“It’s common scientific knowledge that if you have a lot of insulin in your bloodstream it causes inflammation in your arteries and elsewhere in your circulatory system, and this inflammation is a precursor to numerous different coronary artery factors.
“Not only that – when you do this, you’re stressing the beta cells of your pancreas, and also your adrenal glands and your thyroid. I’m seeing some people lately that are into raw foods that are running into adrenal and thyroid problems. This shouldn’t be happening. If you’re over-stressing your endocrine system this can definitely lead to serious problems later on in life.”
I personally think it is a good thing that most of us feel so terrible on a fruit-based diet we’re unable to stick with it long term. I believe we’re the lucky ones.
We feel perpetually hungry, light-headed, spaced out, tired, and/or any and all other signs of malnutrition and extreme blood sugar imbalance.
Some might encourage us to ignore these signs and carry on; that they’re “just detox” and to be expected.
Beware of believing them.
I’ve come across far too many people who started out with multiple nutrient deficiencies, adrenal exhaustion, chronic fatigue and/or eating disorders, and have made those problems much worse by eating high fruit.
It’s a diet that will, in most cases, only exacerbate those problems.
Those suffering from them – and indeed most of the rest of us, too – are much healthier and happier on a diet that is lower in sugar and higher in minerals and essential fats.
I think the reason so many stay on the high-fruit diet even when their bodies are giving them such clear signs it isn’t working is the seductive “natural diet” argument.
The one that had me convinced for years, too.
If it still convinces you, I recommend starting here.