Raw foods get a lot of hype for their nutritional power, and it's deserved in many cases. While a 100 percent raw diet's health value is questionable, cooking or overcooking does destroy some of the vitamin content in certain foods [source: Furhman].
For a person eating the standard American diet heavy on meat, dairy, and overcooked vegetables, adding more raw fruits and veggies will certainly do more good than harm. But don't raid the farm just yet – some foods should never be eaten raw.
Many of the compounds that make plants on this list too toxic to eat raw are part of their defense mechanisms. Toxins like deadly ricin in castor beans or hydrogen cyanide in almonds are designed to deter pests. To plants just trying to survive, we come across as much of a pest as slugs or aphids do.
Some of the foods that you should never eat raw are on this list because they're poisonous without cooking. Not all of the toxic foods here will kill the average healthy adult. Some will just give you a wretched belly ache or other mild to moderate symptoms. And one of these foods isn't unsafe, but it needs to be treated to keep it from tasting terrible. Read on, and while you're at it, go ahead and put that water on to boil.