Originally posted at http://www.rawpaleoforum.com/welcoming-commitee/unavailable-grass-fed-meat/msg21512/#msg21512:
Well, the odd thing to me is how we always utilize science and measurements when deciding whether something is harmful or not. It doesn't feel intuitive to look into the amount of sugar (with no mention of what kind of sugar) and conclude that it has to be harmful. Does eating 15 bananas in a day have a harmful effect on blood sugar? Does it causes energy highs and lows? Is it bad for you in combination with high fat intake or simply in and of itself? Right now all I get is contradictions depending on which camp you ask the questions to. That Steve Pavlina guy was testing his blood sugar throughout the 30 day vegan diet and it all played out normal. ....
One thing you could do, if you don't mind the expense, is buy a glucose meter (most come with a sample of test strips) and do some of your own blood sugar testing, instead of relying solely on Pavlina's example.
I had done a fair amount of research on bananas, because I was surprised to find out recently that they were inedible during the Stone Age, and that got me investigating. Your questions got me doing some additional research. Here are some of my findings:
"Wild bananas are native to SE Asia, and produce inedible fruit with numerous seeds but little pulp" and bananas made edible by domestication were not eaten by Westerners until the 15th and 16th centuries when "Portuguese colonists started banana plantations in the Atlantic Islands, Brazil, and western Africa" (sources: "Banana - Trade, Cultivation, Pests and diseases, Effects of banana diseases in East Africa, Fibre, Popular culture,"
http://encyclopedia.stateuniversity.com/pages/2306/banana.html and "Wild Bananas," La Gringa's Blogicito, Tuesday, November 14, 2006,
http://lagringasblogicito.blogspot.com/2006/11/wild-bananas.html). Until the 19th century, even domesticated cultivars of bananas had to be cooked to be made edible:
"The yellow sweet banana is a mutant strain of the cooking banana, discovered in 1836 by Jamaican Jean Francois Poujot, who found one of the banana trees on his plantation was bearing yellow fruit rather than green or red. Upon tasting the new discovery, he found it to be sweet in its raw state, without the need for cooking" ("Banana History: Cultivation of bananas pre-dates that of rice," Peggy Trowbridge Filippone,
http://homecooking.about.com/od/foodhistory/a/bananahistory.htm).
Americans did not start eating large quantities of bananas until fruit conglomerates like United Fruit Company began shipping large quantities in the late nineteenth century ("United Fruit Company,"
http://en.wikipedia.org/wiki/United_Fruit_Company#Early_history). United Fruit is now Chiquita, which continues United Fruit's practice of monoculture agriculture of a single cultivar (the Cavendish yellow banana), made possible by heavy chemical use, that eventually led to the demise of the earlier Gros Michael variety and which is predicted to end with the demise of the Cavendish within the next 10-20 years ("Bananas Are Dying, Killed by Corporate Monoculture," Heidi Stevenson, 2 June 2008,
http://www.naturalnews.com/023339_banana_bananas_disease.html and "Banana,"
http://en.wikipedia.org/wiki/Banana). So even if you are young and love yellow Cavendish bananas and think they are healthy, you will likely not be eating them 20 years from now and 30BananasADay.com has a limited future (unless there is a switch in focus to other varieties than the Cavendish bananas in the site logo).
Most of the bananas that grow wild in SE Asia today are apparently descendents of past domesticated cultivars. For example, many wild bananas grow in the Philippines, but they are not native to that nation. Since wild bananas are inedible, the earliest uses might have been the uses that wild bananas are put to today: using the seeds to make necklaces, the leaves for roofing materials, umbrellas and plates, the flowers for decoration, and the starch to brew alcoholic beverages (The Encyclopedia of Fruit & Nuts, by Jules Janick, Robert E. Paull, p. 514). It's my guess that that latter use is what spurred the first spreading by humans of wild bananas beyond their native land of New Guinea.
I do not know a single scientist who thinks that the few centuries that Europeans have been eating bananas, or the less than two centuries that Americans have been eating them is enough time to adapt biologically to a food. So the question is, are bananas similar enough to other fruits that we could be biologically pre-adapted to eat them without long-term harm, despite most of the world not having consumed them regularly until the 19th century? I don't know.
I do know that despite bananas containing loads of potassium I continued to get potassium-deficiency cramps while I was eating plenty of them, whereas the cramps rapidly declined when I cut out carbs and started eating raw red meats regularly (and only return if I go too long without eating raw red meat)--despite the fact that red meat contains lower levels of potassium. So either the potassium in red meat is more bioavailable to me than that in bananas, or the carbs in any food, like bananas, reduce the bioavailability to me of nutrients like potassium, or both. So for me bananas are not a prime food choice for at least three reasons. As always, YMMV.
Another interesting piece of evidence regarding diets heavy in fruits like bananas is the fact that the 30bananasaday and other raw vegan forums seem to be filled with complaints of poor health, cravings and detoxes, whereas this forum seems to have more reports of health benefits than health complaints (though we do have some of the latter). Yet when people like you report at a raw vegan forum having problems with a raw vegan diet, they tend to get dismissed or excuses made. Have you noticed this when comparing 30bananasaday to this RPD forum?