I mentioned earlier, when discussing the case of the 88-year-old woman who suffered bok choy poisoning, that most of the toxins in our bodies come from plant foods.
This is a surprise to most, since we have been taught to regard vegetables as healthy, to fear meat and fats, and to fear above all synthetic environmental toxins like pesticides.
Yet the volume of plant toxins which our bodies must deal with from our daily food is remarkable. Bruce Ames and Lois Gold of the University of California at Berkeley report:
About 99.9% of the chemicals humans ingest are natural. The amounts of synthetic pesticide residues in plant foods are insignificant compared to the amount of natural pesticides produced by plants themselves. Of all dietary pesticides that humans eat, 99.99% are natural: they are chemicals produced by plants to defend themselves against fungi, insects, and other animal predators….
We have estimated that on average Americans ingest roughly 5000 to 10,000 different natural pesticides and their breakdown products. Americans eat about 1500 mg of natural pesticides per person per day, which is about 10,000 times more than the 0.09 mg they consume of synthetic pesticide residues. 
They also note that 57% of natural plant compounds tested have proven to be carcinogens in rats and mice, compared to 60% of synthetic compounds tested. In general, plant pesticides are as potently toxic as synthetic pesticides.
Should you run in terror from the supermarket vegetable aisle? No, not at all: it’s better to back away cautiously, to avoid being noticed. (Just kidding; in fact we recommend eating 1 to 2 pounds of plant foods per day, including vegetables!) But it’s prudent to diversify your plant food consumption, avoid the most toxic foods like grains and legumes, and cook most vegetables.
 Ames BN, Gold LS. Paracelsus to parascience: the environmental cancer distraction. Mutation Research 2000 Jan 17; 447(1):3-13. http://pmid.us/10686303.