http://www.psychologytoday.com/blog/animals-and-us/201106/wh...

In her early 30's, Staci's health started going downhill. After twelve years of strict vegetarianism, she began to suffer from anemia and chronic fatigue syndrome, and she experienced stomach pains for two hours after every meal. "I was completely debilitated," she tells me. "Then I changed the way I ate."

The point here is not to bash vegetarianism, but to point out that it took her 12 years to develop health issues. And that's with vegetarianism, that is often considered a very healthy way to eat. So I would expect more potential hazards from something new, untried and untested.

It's not about your body suddenly running out of a nutrient five years down the line. It's about your body starting to repair and build structures that need to last for years while missing key ingredients.

As a random example, people can develop osteoporosis after years of drinking diet soda.