Who has evidence that eating a lot of fruit is unhealthy? We have good reasons to be scared of fructose used in soda and other processed products. That's whay most paleo's eat fruit in moderation, I think. But is there any evidence that there are negative consequences for our health?
Please, this time I'm not interested in personal anecdotes (although they are important), nor in theories, but in hardcore evidence.
There is no hardcore evidence.
Have you read Ms. Minger's recent post: http://rawfoodsos.com/2011/05/31/wild-and-ancient-fruit/
That's not proof but an interesting read on the 1000's of species of fruits out there.
I understand that fructose and sugar is a concern for many people but quite honestly I feel the fear is irrational in most contexts. After all we were eating fruit before we figured out how to eat meat. Eating whole foods is a big picture approach to nutrition yet we isolate sugar and fructose out of the many many compounds in fruit and pretend that sugar and fructose act in a vacuum.
There are two things I know I liked as a child meat (and all it's trimmings) and fruit. I still eat a lot of fruit and suck on limes just like the rest of my family in Okinawa. We tend to live longer than most so I'll continue to trust those instincts. My great grandma just died at 106 and my grandma is still alive and mobile as well. Grandma always encouraged us to eat good meat and fruit and I've never seen anybody completely destroy a chicken quite like her (it wasn't even worth throwing the bones to the dog after she finished with them). In the summer she'd always give us eggs every morning and fruit and for lunch/dinner some type of meat usually pork. She loves a good pork chop. She has several fruit trees in the backyard.
Peter at Hyperlipid has a number of posts on fruits and vegetables that are not very rosy. Nothing about just fruit, but very interesting:
From the first link:
"CONCLUSION: Among survivors of early stage breast cancer, adoption of a diet that was very high in vegetables, fruit, and fiber and low in fat did not reduce additional breast cancer events or mortality during a 7.3-year follow-up period."
Pretty conclusive. No mincing of words.
You could say it didn't do any harm I guess.
How about the arguments of those who are for fruit?
Ray Peat (the anti-PUFA, pro saturated fat scientist) is quite pro-fruit and somewhat anti-green leafy vegetables.
A particular plant will have a variety of defensive chemicals, with specific functions. Underground, the plant’s roots and tubers are susceptible to attack by fungi and nematodes. The leaves, stems, and seeds are susceptible to attack by insects, birds, and grazing animals. Since the plant’s seeds are of unique importance to the plant, and contain a high concentration of nutrients, they must have special protection. Sometimes this consists of a hard shell, and sometimes of chemicals that inhibit the animal’s digestive enzymes. Many plants have evolved fruits that provide concentrated food for animals, and that serve to distribute the seeds widely, as when a bird eats a berry, and excretes the undigested seed at a great distance. If the fruit were poisonous, it wouldn’t serve the plant’s purpose so well. In general, the plant’s most intense toxins are in its seeds, and the fruits, when mature, generally contain practically no toxins. Roots contain chemicals that inhibit microorganisms, but because they aren’t easily accessible by grazing animals and insects, they don’t contain the digestive inhibitors that are more concentrated in the above-ground organs of the plant.
Generally, fruits, roots, and tubers provide a high concentration of nutrients along with low concentrations of toxic antimetabolic substances.
Despite its name, fructose is not only found in fruits, but also vegetables. Carrots, onions and sweet potatoes all have fructose.
I agree with Ned Kock that fructose in fruits may be good for you and only raises triglycerides in sedentary people eating large amounts of it (such as in soft drinks).
The HFCS debate is merely a lightning rod for criticism of processed food and added refined sugar. I think that is more what it is about than HFCS itself. The same people criticizing HFCS, are not going to be the type of people who extol "natural" cane sugar or corn syrup over HFCS. I definitely think the debate over HFCS has made it so people are wary of fructose in fruit and vegetables. I'm not worried.
Wild fruits are probably more nutrient dense (correct me if I'm wrong). Whereas an apple or a banana may not seem like much now in the way of nutrition. Soil depletion and over-domestication has probably decreased a lot of nutritional value. Fruit is definitely healthy, but it may be even healthier to choose less domesticated or wild fruits.
fruit juice.. not the same i know, but.. http://pediatrics.aappublications.org/cgi/content/abstract/99/1/15
Obvious problem for diabetics or prediabetics, whose glucose metabolism is already damaged. ALso potential problem for those who are not diabetic but with damaged metabolism and gain weight easily or are sugar addicts. Other than that, I see no reason, so far, to fear moderate whole fruit intake. However, I would agree it would be nice to see more research on it. Sadly, I think too many theories go straight from theory to fact without the intervening research. That's what has probably happened with fruit intake. Since 'everyone knows' it is good for you (and mainstream media includes fruit juice in that one), then they feel there is no reason to study it. As a former fruit juice addict that would go into the fridge about once an hour for a swig of sugar/fruit juice, I can say with confidence that fruit juice causes problems for some people, but I do seem to do OK with whole fruit instead.
The effect of a high consumption of citrus fruit and a mixture of other fruits on dental caries in man.
The number of subjects included was: for the citrus-producing group 120 (55 men), for the mixed variety group 95 (49 men) and 50 (25 men) for the grain-producing group (control group)....
...The mean daily intake of added sugars (excluding that from the specific fruits to be investigated), was the highest for the control group...
...However, the highest DMFT (24.8) was found in the citrus-producing group, with less in the mixed variety fruit group (22.7) and the least in the control group (9.9). The sequence of the order of magnitude of the components (D, M, F) of the DMFT was the same as that for the caries experience as such. It is concluded that a high consumption of various fruits over a long period is associated with a high caries experience.
dmft=decayed missing filled teeth
Might not be unhealthy but it will probably rot your teeth out eventually.
Fruit itself probably does not wreck your metabolism. It is theoretically possible since it has fructose and fruit has higher sugar than vegetables and any other whole foods. But there is no evidence that fruit alone caused diabetes. Of course, things have changed a bit now, since all fruits are sweeter, bigger, and pack more fructose per gram than ever before.
Having said that, how many people only eat fruit and abstain from grains and other forms of sugar, what Dr. Lustig might call "exogeneous sugar." Very little, if any. We probably have the Kitavans and other Polynesians who were not exposed to gluten flour and exogenous sugar.
But consider a Joe Sixpack who wants to dig into his slice of apple pie: pie fillings filled with sugar, gluten crusts, and lots of exogeneous sugar. What you ate is toxic sugar explosion, not any fruit. There are very frew "fruitarians" in the West that are eating just fruit, veggies, and meats. The minute you mix fruit with gluten or exogenous sugar, you magnify the toxidity of fructose, whether deriving from whole foods, artificial sources, or from exogenous sugar. That's the argument.
A verty interesting article. The bit you need is on page 3.
Heirloom produce -- a wiser selection? 2 Answers