Fruit without fat = fabulous?
January 25, 2010 5:00 PM   Subscribe

My roommate claims a diet consisting of mostly fruit is OK as long as she keeps it low fat. Is there any science to back up this claim?

Basically, she says it's only isolated sugars that cause blood sugar problems and that fiber and the other nutrients in fruit mean that consuming a diet of mostly sugar is OK. I found one study that said the the sugar in fruit can cause problems, but she says that doesn't count because it only causes problems in people consuming too much fat. Does anyone know if any studies have been done on this?
posted by idle to Health & Fitness (39 answers total) 4 users marked this as a favorite
Well, we're descended from frugivores, so it can't be that bad. But there important things you'll need, like salt, to be healthy.
posted by Ironmouth at 5:05 PM on January 25, 2010

you might try searching fruitarianism - although, is she also avoiding nuts?

pretty much any diet that isn't balanced is going to be bad for people. our bodies like diversification.
posted by nadawi at 5:06 PM on January 25, 2010 [1 favorite]

The book you want to read about this is Good Calories, Bad Calories by Gary Taubes. The short answer is she's wrong, but probably not for the reasons you'd think.
posted by Nattie at 5:13 PM on January 25, 2010

I know you said "mostly" but my first question is where she gets protein.

Eating ten oranges a day is not necessarily "healthy".

As mentioned, balance is the key to eating well.
Mostly fruit is not any more balanced than mostly vegetables or mostly meat.
No dis on vegetarians, but those who do it well add in forms of protein like nuts or tidy or legumes etc.
posted by sio42 at 5:15 PM on January 25, 2010

Yeah, this depends heavily on what you mean by "mostly" fruit.
posted by Justinian at 5:18 PM on January 25, 2010

I'm meaning ridiculous amounts of fruit, like ten oranges and ten bananas and ten apples...
posted by idle at 5:20 PM on January 25, 2010

If all she's eating is fruit, where would the fat becoming FROM?
posted by EmpressCallipygos at 5:24 PM on January 25, 2010 [1 favorite]

"Well, we're descended from frugivores" - it doesn't matter what we may be descended from, it matters what we are. We're omnivores.

A zero protein, low iron, low whole grain diet? She may not get scurvy but she isn't going to be healthy!
posted by carlh at 5:26 PM on January 25, 2010 [3 favorites]

30 pieces of fruit in a single day is something like 5 or 6 times the recommended daily servings. What else is she eating? What grain products does she eat? What are her sources of protein? Is she ingesting any fat (which, in moderation, is actually nutritionally essential)? There are literally dozens of nutrients she's not getting.

A steady diet of nothing but apples, oranges, and bananas is very poor. She may not gain any weight, but she most certainly isn't going to be healthy.
posted by scody at 5:28 PM on January 25, 2010

You shouldn't need studies. When the explosive diarrhoea kicks in it should convince anyone there's something wrong with their diet.
posted by Silentgoldfish at 5:30 PM on January 25, 2010 [15 favorites]

If she thinks that "lots of fruit" plus "low fat" means healthy in any way, she has absolutely no idea what she is talking about and you should not follow her lead.
posted by ch1x0r at 5:41 PM on January 25, 2010 [2 favorites]

Wow, that is a terrible idea. She's getting the bulk of her calories from carbohydrate, with next to no protein or fat. In order to not die of malnutrition, a person needs to eat some of each of those fuel sources.

Additionally, there are a whole shitload of fat-soluble vitamins that this person will not be getting any of. Even if she supplements, there won't be any fat for the vitamins to dissolve in, so they won't be properly absorbed.

Humans evolved to eat a wide variety of foods. Being omnivorous gives us a lot of flexibility in our diet, but also basically mandates us to BE flexible in our food selection, since that is what we are adapted to. We are not the fruit-eating bat. In principle, this is no different from saying that it's OK to eat nothing but bacon and chicken wings, because your diet will then be low-carb.
posted by kataclysm at 5:45 PM on January 25, 2010 [1 favorite]

pretty much any diet that isn't balanced is going to be bad for people.

Yeah, this. That's a lot of fruit but it depends on what else she eats and how much energy she burns. Fruit still contains energy, and while sure the fibre etc will help prevent a blood sugar spike (note: 'help' not definitely prevent) she's still loading herself with sugar. There are problems with that besides blood sugar and if she's consuming too many kJs each day she'll gain weight regardless of where they come from (sugar, fat, protein, whatever). Fruit is a better choice than straight sugar and it has health benefits of it's own but it isn't some magic thing you can eat without consequence.

If she's really active and burning off all that sugar then it's not so bad, although it would be difficult to do that while also getting enough complex carbohydrates, fat, and protein. But if she's eating fruit in place of other food then it's more likely that her diet will be unbalanced. We do actually need a certain amount of fat to be healthy, for example, and eating none is unhealthy same as eating lots and lots (although for different reasons of course).

A diet of mostly sugar most definitely isn't OK, a diet of mostly anything isn't OK. She doesn't need one specific study, she needs to read and learn more about nutrition in general because right now she's picked one isolated factoid and made up a whole lifestyle justification about it when really humans are just way more complex than that.
posted by shelleycat at 5:54 PM on January 25, 2010

Does she eat any protein of any kind? Any calcium? Anything with some iron? And everyone needs to eat some fat to live and be healthy.

Your room mate may be a dumbass, or she may be in the early stages of an eating disorder. If she's still open to logical persuasion, enter her typical day's eating at a site like FitDay, which will show her nutrient intake for the day. I tried your example of 10 apples, oranges and bananas and got the following. The stuff in bold is especially worrying:

- Calories: 2,384 (more than most sedentary young women of average size need every day)
- Fat: 7.8 grams (The RDA is 65 grams, although some low fat dieters WHO ARE EATING A WIDE VARIETY OF OTHER FOODS may be able to get by on 30-40 grams. The extremely low fat levels she displays are a bug, not a feature. She's more likely to feel cold and have aching joints. She may also develop dry, dull hair and skin, among other cosmetic issues)
- Carbohydrate 614.0 grams (2210 calories worth, 93% of total calories)
- Dietary Fiber: 95.2 (fiber is good. However, spending all day on the toilet isn't that much fun)
- Protein: 28.8 grams (this is well below the RDA for an adult. She may lose muscle.)
- Vit A: 38% of RDA, even after eating all that fruit
- Vit B12: 0% of RDA (you need supplements or food from animal sources)
- Vit C: 863 mg, 1151% of RDA
- Vit D: 0%
- Vit E: 40%
- Calcium: 67%

- Copper: 209%
- Iron: 34%
- Magnesium: 162%
- Manganese: 222%
- Niacin: 91%
- Vit B5: 161%
- Potassium: 172%
- Riboflavin: 159%
- Selenium: 33%
- Thiamine: 158%
- Zinc: 40%

In summary: if this is a diet to lose weight, she's not keeping herself healthy in the process.
posted by maudlin at 6:11 PM on January 25, 2010 [3 favorites]

she says it's only isolated sugars that cause blood sugar problems

She's wrong.
posted by Civil_Disobedient at 6:25 PM on January 25, 2010 [1 favorite]

Just off the top of my head, she's in for a nice, healthy dose of anemia and rickets.
posted by Civil_Disobedient at 6:29 PM on January 25, 2010

Most books on vegan nutrition will warn you about B12 deficiency. It's quite real. Not only are fruits alone not enough; fruits & veggies are not enough. It will take a long time for the deficiency to show up though.
posted by chairface at 6:38 PM on January 25, 2010 [1 favorite]

An interesting case of what happens when you stress your body without consuming at least some fat: rabbit starvation. I'm not smart enough to extend the examples to an all fruit diet, but I think it serves as a cautionary example of taking things too far.
posted by sbutler at 7:02 PM on January 25, 2010

eating only ___________ is bad. period.
posted by swbarrett at 7:07 PM on January 25, 2010 [4 favorites]

I don't know about studies of fruit-only diets. But there is VAST body of studies trying to identify the minimal requirements to support human health. This is how we know what vitamins are, how we know what essential fatty acids are, how we know what essential amino acids are, what essential minerals are. Whether or not a fruit only diet supplies too much sugar or whatever, it is easy to see that a true fruit-only diet doesn't have enough of many essential nutrients. It would be interesting to know what your friend means by "mostly fruit".

Since your friend is probably obsessed with the natural, you might point out that our closest primate relatives eat vegetables, tubers, eggs, insects, whatever small creatures they can catch, and even carrion. They absolutely do not eat fruit only. Humans of course have a much bigger brain to support and need even more calorie-dense food than a chimp.
posted by i_am_joe's_spleen at 8:01 PM on January 25, 2010

Well, we're descended from frugivores, so it can't be that bad.

Yeah, but the major evolutionary descent happened because* proto-humans figured out how to eat bone marrow...

Huh, I was going to look up a cite for the bone marrow -> evolutionary quantum leap thing, and I stumbled upon this site devoted to debunking pro vegetarian-type arguments. It's probably biased, but there's some good info about fruitarianism, including a lot of "mythbusting" (e.g., this and this) and the author gives plenty of citations.

Also, I'll echo that humans require dietary fat. Damn that 1980s Susan Powter brainwashing.

*or at least "when"
posted by sentient at 8:04 PM on January 25, 2010 [1 favorite]

If all she's eating is fruit, where would the fat becoming FROM?

Don't forget about avocados.
posted by sentient at 8:07 PM on January 25, 2010

Yeah. Even raw foodists know the necessity of veggies (calcium, for instance? among many other things) and nuts (protein and fat.)
posted by Solon and Thanks at 8:10 PM on January 25, 2010

I went through a period where I was eating 13 pounds of oranges a week (they're fairly low in calories, and I like fruit).

$2000 worth of fillings later, I realized it was also a very high sugar diet.

Just a warning.
posted by Comrade_robot at 4:30 AM on January 26, 2010

The diet she is following is this
If too much sugar is not good for you, why the emphasis on eating so much sweet fruit?
Before the body's cells can utilize food for fuel, the food must first be converted into sugar, whether the originating food is carbohydrate, protein, or fat. Carbohydrates are the easiest to convert to useful sugars. Fruits are mostly simple carbohydrates. It is much easier on the digestive system to process fruits for fuel because they are composed primarily of sugars, requiring much less digestive energy, and they come in a complete nutritional package of vitamins, minerals, proteins, and fats. When there are insufficient carbohydrates present to convert to sugar, the body will transform fat and protein into sugar, but at a higher cost: more time and energy spent on digestion with the creation of toxic residues.

She told me to check out all the people who are successful like this girl
posted by idle at 6:39 AM on January 26, 2010

First hand experience: she will end up in the hospital unless she eats a variety of foods. It is ok to eat animals as well.

She's either totally a sucker or is falling down the slippery slope of eating disorders.
posted by WeekendJen at 7:17 AM on January 26, 2010

This pings my eating-disorder radar a little. I don't intend to make assumptions about your roommate - she could be in the prime of health for all I know - but this is the type of diet that people either flirting with or embroiled in eating disorders tend to use as a cover. (Diets with ED appeal tend to have very strict, sometimes arbitrary guidelines, often ignore any notion of dietary balance, and in general just look weird compared to the average healthy diet.)

You don't mention why she's following this diet. Weight loss? She will probably lose weight, but she will not feel well. If she's working out, too, she won't have the energy to perform her best, and she needs protein to build and maintain muscle.

I'm also curious how long she's been following the diet. Weird diets like this are pretty hard to sustain - after a few days, the lack of protein and fat tends to catch up and you feel like shit. If she sticks with it, and especially if she starts adding weird additional rules or eating rituals, she could be well on her way to an eating disorder.

Finally - the foodnsport FAQ talks a lot about toxins. I've found that it's generally a safe bet to assume that any product or program that mentions the word "toxin" is bunk.
posted by Metroid Baby at 7:39 AM on January 26, 2010

Perhaps giving her information about fat soluble vitamins (A, D, E and K) would help. Humans absolutely need fat in order to process things effectively. Low fat diets also prevent healthy calcium absorption which will lead to osteoporosis later in life.
posted by stoneweaver at 10:24 AM on January 26, 2010

As soon as I read this in their FAQ, I stopped:

"There is no essential nutrient in meat, grains, legumes, or dairy that is not also available in fruits, vegetables, nuts and seeds, and in a form that is easier to digest."

That's just bullshit. Eg, iron. Easiest to absorb as heme iron from meat, hardest to absorb from plants, where it is a different form and typically comes with substances that inhibit uptake. Eg B12, which doesn't have any plant sources at all.
posted by i_am_joe's_spleen at 10:36 AM on January 26, 2010 [1 favorite]

Also, it's great that there are people who are successful on this diet. But, your friend is assuming they're telling the truth, that they haven't just started it, and that they wouldn't be even healthier on a more balanced diet. She is also not thinking about all the ones who got sick or couldn't keep up with the regime don't have websites, and I'll bet you a brick to London that there are many, many more of them.

I doubt very much whether your friend will be persuaded one way or the other, but don't you get sucked in.
posted by i_am_joe's_spleen at 10:41 AM on January 26, 2010 [2 favorites]

She told me to check out all the people who are successful like this girl

Fair or not, this is now starting to have a (faint, citrus-y) scent of viral marketing about it.

posted by scody at 11:23 AM on January 26, 2010

I showed her this site

But she just keeps going on and on about all the people who are successful on it. I'm really just disturbed because of the psychology of the whole thing: making people feel guilty about "dirty" food and saying that if people have a problem it's because they are eating wrong. Acne? You must have eaten too much fat, or maybe the fruit is pulling "toxins" out of your body.

I directed her to this girl, who also looks pretty good

Her diet....french fries.

I guess my wish was to find a study on people where they fed them fruit and it showed a negative effect. I did find a few studies on negative effects
like low bone mass
and dental erosion. She said it's because the people in the studies ate too much fat and light bones are healthier anyway.

I think I am just fighting a losing battle. Hopefully she will learn on her own before her teeth fall out.
posted by idle at 12:03 PM on January 26, 2010

Here is more stuff in case other people have the same problem (at least she won't leave dirty cooking pots in the kitchen anymore)
Child who died from fruitarian diet: appears more vulnerable are especially subject to the deficiencies of this diet.

It's also notable that according to google scholar, such diets have been around for over 100 years. . I am admittedly a little impressed that Josiah Oldfield lived to be 90, but it seems his diet wasn't really just fruit.
posted by idle at 12:18 PM on January 26, 2010

Now I'm just amused by Josiah Oldfield. His diet actually seems like the fruit cobbler diet, which is a diet I could definitely follow. Here is the recipe from the blog post above
Margaret Plum Pudding.
(as used at the Lady Margaret Fruitarian Hospital) .
One pound of grated bread-crumbs, one pound of stoned raisins, one pound of sultanas, half a pound of candied peel, half a pound of sweet almonds, a few bitter almonds, a quarter of a pound of butter, half a pound of pine kernels, a quarter of a pound of shelled Brazil nuts, half a pound of brown sugar, the grated rind of threelemons, six eggs. Finely cut up the peel and blanch all the nuts, except the pine kernels, pass through the nut mill; the latter are to be simply chopped. Rub the butter into the bread-crumbs; add the fruit, sugar, grated lemons, and lemon peel; then the eggs, well beaten and mixed together. Put into a basin and boil in the usual way for six hours. The eggs may be replaced by a cupful of milk, half a cup of syrup, and a teaspoon of baking powder.
(Dr. Josiah Oldfield, Fruitarian Diet.)

I also thought bitter almonds were despite the deliciousness of all the butter here, I probably wouldn't eat this.

posted by idle at 12:23 PM on January 26, 2010 [1 favorite]

That paragraph you posted up there from their site is full of bullshit. There isn't one single study available to refute it or one thing it's got incorrect, it's just all wrong. I didn't read the site because I don't feel like being pissed off this morning, but feel free to tell your flatmate that a nutritional biochemist looked at the blurb and was horrified that it's being put out there as fact. I'm betting the 'successful' people are also made up, either that or they're building up all kinds of nice health problems for the not-so-distant future.

So follow the money. Who's making something from pushing this diet? For example, those fancy fruit juices that are supposed to save your life in however many ways are a MLM scam, or the Atkins diet is all about pushing books. Find who's making the money and then you should be able to figure out why they're pushing such false information and hopefully break her attention that way. Making up successful end users is a pretty common trick of quack remedies and health food scams, so that's another angle to attack from.

light bones are healthier anyway.

Yeah you are fighting a losing battle. Your room mate has no fucking clue. Again you don't need single studies to refute this but a complete overhaul in her understanding of human health and nutrition, which probably isn't possible while she's under the influence of this fad diet.
posted by shelleycat at 1:30 PM on January 26, 2010 [2 favorites]

At first the op claimed this was a fruit only diet. But following the links I am seeing that the diet she is following is 80% carbs, 10%protein, 10% fat.

Which seemes to be a way for another evangelistic food guy to make his buck. But he is basing his diet on a pretty typical raw, vegan diet. It is possible to have a healthy, raw, vegan diet.

Heres where you have to be careful. Raw foodists are pretty well established. They have heard all of these arguments before. If they have done their research, they will be more aware of these problems than you are. They are even told to expect resistance to their diet choices from people who eat a standard American diet(SAD).-see what they did there? So if she is really into this and you attack it, you may be written off and lose a roommate. I have seen many co-housing situations break up because of differing dietary choices.

On the other hand, like any strict diet. Most people end up cheating or changing up their diet sooner or later.

My suggestion is to discuss b12 and iron with her and then support her choice. Look at this raw menu. See if you can obtain something similiar and then surprise her for dinner some night. I suspect that a little more of this type of food in your diet wouldn't hurt a bit.
posted by psycho-alchemy at 1:32 PM on January 26, 2010

Yeah, I'm familiar with normal raw veganism having gone to some potlucks now and then and tried it on and off. I'll always be indebted to raw veganism for introducing me to thai young coconuts, some pretty awesome gluten-free dessert recipes, and nori wraps (all of which are forbidden on my roommates diet...she can have like half an avocado or something). I'm afraid I'm the one who tipped her off to raw and she found this fringe thing through that.
posted by idle at 1:55 PM on January 26, 2010

Sorry to assume otherwise, my friend was a raw-food chef and she got attacked by people not too infrequently.

If you have the social network of other raw-foodists, then perhaps you can have them fight your battle for you. Get her to a potluck with some evangelical raw foodists, who happen to know their shit.
posted by psycho-alchemy at 10:31 PM on January 26, 2010

I could be wrong, but the obsession with fat and the thing about low bone density (which is insane, there is nothing good about low bone density) really makes this sound like your roommate has decided to have an eating disorder and is just looking for excuses that sound kind of sciency. I doubt that reasoning with her about nutrition will work if she is mentally ill in this way, because it's not really about food.
posted by A Thousand Baited Hooks at 12:03 AM on January 27, 2010

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