Whenever I read or hear this question, my mind always goes back to the 1973 Woody Allen movie "Sleeper". In that movie, Allen's character, Miles Monroe, is awakened from a 200 year, cryogenic sleep. While trying to familiarize Monroe to the world he has awakened to, doctors tell him, "Everyone you ever knew is dead". Monroe looks at them in disbelief and responds, "But they ate organic rice!". The point is that no matter what we do, how we live our lives, or even what we eat, we are all going to die. As far as vegetarians living longer, healthier lives, diet is only one aspect contributing to longevity and it is impossible to say that adjusting just that one aspect will absolutely influence the outcome.

There are so many stories providing conflicting evidence. On one hand, you have people like Bette Davis who smoked five packs of cigarettes a day, washed them down with a fifth of whiskey, and ate whatever she wanted. She lived well into her 80's. On the other hand, there are people like Jim Fix who ran 10 miles everyday, yet collapsed in the street dead from a heart attack in his 30's or Ewell Gibbons who proclaimed that many parts of a pine tree are edible and encouraged us to eat Grape Nuts. He died of malnutrition. The single aspect of diet appears to have little bearing in these three lives, except for Gibbons, who may have taken the vegetarian "thing" a bit too far.

The truth is that longevity is combination of factors with the most important being "genetics". If we all lived in a vacuum, lead exactly the same healthy lives and ate exactly the same healthy foods, the people with the best genetics would live the longest. Outside the vacuum, environmental factors are more relevant. Risky behaviors, risky jobs, risky habits and other factors that put individuals in harm's way can intervene against genetics and shorten an otherwise long live. Yet, even in those circumstances, the best genetics will still survive the longest if the danger can be avoided. Believing vegetarians will live longer and happier simply because of diet just exemplifies the way people tend to think. It is easier for people to consider one, simple solution rather than a more complex and involved solution to a more complex and involved problem. A good example is a common weight-loss diet.

When people diet to lose weight, many believe taking pills or limiting consumption is all that is necessary. Naturally, most of those people fail because they don't get proper nutrition, they do not include adequate exercise, and they just have poor genetics. Even a vegetarian diet is no guarantee of weight loss and improved health because many vegetarian foods are not low fat. Besides, to be certain, no one can agree on exactly what constitutes a vegetarian diet.

There are people who eat fish, but still call themselves vegetarians, there are people who eat chicken, but still call themselves vegetarians and there are people who eat dairy, but still call themselves vegetarians. For the record, the only true vegetarian diet is a "vegan" diet that excludes all animal products and very few people, even vegetarians, go that far. I am not even sure it is entirely healthy. All vegetarian diets tend to be low in calcium, iron and zinc, not to mention vitamin B12 and gelatin. If people on vegetarian diets do not supplement to gain these nutrients or vary their intake to ensure adequate consumption, they will develop health problems, albeit different health problems, just the way anyone on a meat-based diet will.

People who are really concerned about longevity and health can improve their odds by weighing their diets toward the vegetarian side, but none should rely on that one, lone aspect to cover all the bases. A long, healthy live is the result of a combination of factors including limiting life-threatening risks, getting adequate exercise, limiting consumption, maintaining a good weight, avoiding undo stress, getting plenty of rest, eating a balanced diet, and, probably most important of all, being lucky enough to be born with good genes.