The Proof 

The U.N. report concluded that the meat industry is "one of the ... most significant contributors to the most serious environmental problems, at every scale from local to global." The U.N., in its 408-page indictment of the meat industry, specifically addressed the contribution of eating meat to "problems of land degradation, climate change and air pollution, water shortage and water pollution, and loss of biodiversity."

Greenpeace has done just that. The group both walks the walk and talks the talk, serving only vegetarian food at all the organization's events. And they call attention to the connection between meat and environmental degradation on their Web site, noting that a vegetarian diet means "saving vital chunks of rainforest, consuming less raw materials, saving water and generating less pollution." Greenpeace has also targeted KFC for the destruction of the rainforests because the Amazon is being razed to grow feed for KFC's chickens.

But evidence shows that eating animals is the number one individual cause of global warming and that it's in the top three causes of every significant environmental problem, from the smallest to the largest. So it's past time for the environmental movement to tell people the truth--that adopting a vegetarian diet is the most important action any of us can take, both to decrease our support for global warming and also to address our support for all the rest of the "most significant contributors to the most serious environmental problems, at every scale from local to global" (to quote the United Nations).

Intelligent children are more likely to become vegetarians later in life, a study says.
A Southampton University team found those who were vegetarian by 30 had recorded five IQ points more on average at the age of 10.

Researchers said it could explain why people with higher IQ were healthier as a vegetarian diet was linked to lower heart disease and obesity rates

“Scientific data suggest positive relationships between a vegetarian diet and reduced risk for several chronic degenerative diseases and conditions, including obesity, coronary artery disease, hypertension, diabetes mellitus, and some types of cancer... Vegetarians often have lower morbidity and mortality rates from several chronic degenerative diseases than do non-vegetarians... Vegetarian diets offer disease protection benefits because of their lower saturated fat, cholesterol and animal protein content and often higher concentration of folate, antioxidants such as vitamins C and E, carotinoids and phytochemicals... vegetarian diets have also been successful in arresting coronary artery disease.” American Dietetic Association Position Paper on Vegetarian Diets, 1997.

Vegetarians have lower rates of obesity, coronary heart disease, high blood pressure, large bowel disorders and cancers and gall stones. Cholesterol levels tend to be lower and vegetarian diets have been noted to lower blood cholesterol. The vegetarian diet is adequate for the nutritional needs of infants.
British Medical Association 

Although human beings eat meat, we are not natural carnivores. No matter how much fat carnivores eat, they do not develop atherosclerosis [clogged up arteries]. When we kill animals to eat them, they end up killing us because their flesh, which contains cholesterol and saturated fat, was never intended for human beings, who are natural herbivores.
Dr WC Roberts, Editor-in-Chief of ‘The American Journal of Cardiology’ 

The emphasis of our meals needs to be reversed; it is plant foods that should be the focal point of our dinner plate, not meat and dairy products.
World Cancer Research Fund.

Best wishes

cybamonk