It took some convincing to get me to abandon CW's opinion of vegetables. Everybody and his dog agrees on this stuff! Robert Atkins, Barry Sears, and Mark Sisson believe in plenty of veggies! DARE one not get enough soluble fibre and antioxidants, and those vegetable-source-only vitamins and minerals? Surely your colon will rot!
Then you start reading. You learn about Stefansson and you read "Strong Medicine" and "Fiber Menace" and Zeroing in on Health, and you learn that breast milk has no fibre though heaven knows babies poop like there's no tomorrow. You find out that "antioxidants" are toxins-in-small-doses, and that a certain responsible doctor managed many patients for extended periods on no-veg diets, with excellent results.... You start to think that just MAYBE CW is wrong about this, as well as so many other things.
After months of good results, good health and no negative repercussions of minimal plants in my diet, i actually started thinking about WHY eating vegetation might not be the best thing. :-) ...About time, huh?
I already knew about phytates and lectins and such. Plants can't run away or scratch or bite, so they make ingestion as unpleasant as they can for opportunistic predators. Point taken. The more plants you eat, the more of certain nutrients you NEED -- that was an eye-opener. Then i reread what Donaldson had to say about vegetables, and a faint memory began to stir. There are all kinds of vegetable foods that people have trouble with. Grains, of course. Nightshades. Peanuts. Citrus. I googled food sensitivities, and the subject of FODMAPs jumped out at me.
I found that the "yellow vegetables" which Donaldon said were largely well-tolerated, mostly belonged to the list of those with low-fructans. Fructans are fructose polymers (strings of fructose molecules), found to be problematic in people who are also inclined to fructose malabsorption -- one of those "duh" things, i should think, but it took me awhile to get there.
Wikipedia tells me that normal healthy people can only absorb 25-50g of fructose at one sitting (and malabsorbers may have a much lower tolerance) -- WHOA. Then i read that the fructose that ISN'T dealt with in the small intestine moves down the line to mess up things, from water absorption in the colon to unbalancing the gut-bugs, causing them to metabolize their unnatural diet into unpleasant by-products. Fermentation ... altered motility ... conditions promoting biofilms ... changing bacterial populations ... decreasing blood levels of tryptophan, folate and zinc ... bad news.
And some people think that 30 bananas a day promote health? Ye gods. My intestines have left me with no doubt: too much plant material = trouble. Now i know another reason why.