A couple of years ago I was reading John Robbins' wonderful book "The Food Revolution" and came across a statistic that blew me away. It was so incredible it moved my husband to finally give up meat. He had already given up beef, pork and turkey but chicken was tough. I'll summarize Mr. Robbins' findings:

Installing low-flow shower heads
John Robbins points out that to conserve water, many of us have replaced the old 3-gallon-per-minute shower heads with 2-gallon-per-minute (or less) low-flow showerheads. If you take a daily 7 minute shower using a low-flow shower head, you'll save almost 2,500 gallons of water per year.

Giving up one pound of beef
To produce one pound of beef takes between 2500 and 5200 gallons of water. So by giving up just ONE POUND of beef a year, you could save double the water you'd save in a year's worth of showers.

If that doesn't convice you to eat fewer hamburgers, maybe these will. (There are thousands of articles with statistics just like these. Just search the web for environment and water. Here's an example.)

In a world teeming with people suffering from profound hunger and malnutrition, more than 70% of the grain produced in the United States is fed to livestock.

Water needed to produce 1 pound of wheat: 25 gallons; Water needed to produce 1 pound of meat: 2,500 gallons

55 square feet of tropical rainforest are destroyed for the production of every fast-food hamburger made from rainforest beef. (There are more species of birds in one square mile of Amazon rainforest than in all of North America.)

An estimated 70% of the clearing of the Amazon is for cattle pasture.

The amount of water that goes into a 1,000 pound steer would float a (Naval) destroyer. (Newsweek article "The Browning of America")

Production of excrement by total US human population: 12,000 pounds/second; production of excrement by US livestock: 250,000 pounds/second