Although the American Food and Drug Administration reassures the public that meat is safe, no long-term studies have been conducted that show what the genetic effects might be from eating meats from hormone-injected and chemically-fed animals. Vegetarians also tend to have healthier diets by the very fact of avoiding meat: their cholesterol intake is dramatically lower than that of meat-eaters and so too is their intake of saturated fats. Vegetarians would also tend to avoid patronizing fast-food restaurants like McDonalds, which peddle MSG, processed cheese, hydrogenated fats, and other heavily processed foods in addition to just meat. We vegetarians are usually more prone to cooking dinner at home using fresh ingredients or seeking out restaurants that cook healthy wholesome foods. Therefore, the act of avoiding meat can lead to a range of healthier eating choices.

However, I know that I will need to take care with my diet and try to incorporate as many whole foods as possible instead of relying on processed items that just happen to not contain meat. For example, a lot of health food stores sell vegetarian frozen dinners. A lot of the times when I am out at a restaurant the only vegetarian menu items are not well-balanced meals and contain mostly starches or dairy products. With a little careful planning a vegetarian can greatly improve their health and overall sense of well-being.
References

Becoming a Vegetarian." Retrieved Feb 29, 2008 at http://kidshealth.org/teen/food_fitness/nutrition/vegetarian.html

The Vegetarian Resource Group. Retrieved Feb 29, 2008 at http://www.vrg.org