Vegetarian Life Span: Can This Diet Help You Live Longer?

Mature Vegetarian

There is a growing body of evidence to suggest a vegetarian diet is key to long life. People choose vegetarian or vegan diets based on factors including humanitarian ethics, concern for animal welfare, or environmental sensitivity, but it appears the benefits of vegetarianism extend beyond those on conscience. A vegetarian diet may actually be the elusive fountain of youth.

Human Digestion

It stands to reason that the diet most likely to lead to a long, healthy life is that for which a particular species is adapted. Many would argue humans are biologically omnivores and that they need some meat protein for optimal nutrition and health. However, not everyone agrees.

In The Comparative Anatomy of Eating, Milton R. Mills, M.D., explores the difference between the digestive systems of pure herbivores, pure carnivores, and natural omnivores. Based on features of dentition and digestion, Dr. Mills concludes that Homo sapiens is biologically a committed herbivore. A few of the human's herbivorous features include:

  • Small mouth with fleshy lips and a muscular tongue
  • Salivary enzymes for digesting carbohydrates
  • Square, flat teeth for grinding plant matter
  • Small stomach and long small intestine
  • Large, complex colon

Just as a dog can survive on a corn-based diet if necessary, humans can certainly survive on meat. But for optimal health, a plant-based diet seems to be a natural choice.

Official Statement

In 2003, The American Dietetic Association and Dietitians of Canada issued a joint statement of position on the health impact of a vegetarian diet. After reviewing available literature, these two organizations asserted a well-planned vegetarian diet is not only nutritionally equal to a meat-based diet, it may actually be superior. Specifically, vegetarians are at a lower risk for many of the common illnesses associated with a reduced life span in the developed world, including:

  • Obesity
  • Cardiovascular disease
  • Hypertension
  • Diabetes
  • Cancer
  • Osteoporosis
  • Kidney disease
  • Dementia
  • Diverticulitis
  • Gallstones
  • Rheumatoid arthritis

Evidence Vegetarian Diet is Key to Long Life

Many scientific studies bear out what some vegetarians have professed to know all along: that a meatless diet is one of the most effective ways to add quality years to your life.

The Effect of Methionine

Scientists have studied the positive effects of calorie restriction on longevity; however, the restrictive nature of such a plan makes it unappealing to most people. An alternative study in mice has determined that simply limiting intake of the amino acid methionine can produce similar results to reducing calories. An essential amino acid, methionine is abundant in animal products and is present in some grains and seeds. A well-planned vegan diet is naturally much lower in methionine than a meat-based diet but still provides ample protein for good health. Researchers speculate the natural difference in methionine content between a vegan diet and omnivorous diet may result in enhanced life expectancy among the vegans.

IGF-1 Activity

Insulin-like growth factor 1 (IGF-1) is a protein that has been considered a pace-setter for the aging process. Animals with higher concentrations of IGF-1 tend to reach maturity more quickly and have reduced life spans compared to those with lower IGF-1 levels. Evidence indicates a whole-foods based, low-fat vegan diet effectively reduces the production of the protein, potentially slowing the aging process in humans.


According to the Canadian Medical Association, obesity is poised to surpass smoking as the leading cause of preventable death in the United States. Currently, the Surgeon General estimates obesity and related factors to be responsible for at least 300,000 deaths annually in the U.S. alone. Clearly, a healthy eating plan associated with a healthy weight would increase health and longevity for many people. A review published in the American Journal of Clinical Nutrition recommended a plant-based diet as a strategy to treat and prevent childhood obesity.

A 2009 study published in the Asia Pacific Journal of Clinical Nutrition examined the differences in body mass index (BMI) and nutritive status between Catholic and vegetarian Buddhist nuns in South Korea. The study found the vegetarian group had a significantly lower average BMI than the omnivorous group, despite the facts that both groups had similar lifestyles and age ranges. The lowest BMI figures were among women who had been vegetarians the longest.

The Obvious Choice

Is it true a vegetarian diet is key to long life? While many additional factors, such as occupation, genetics, and stress levels can influence longevity, vegetarian eating certainly seems to be a contributing factor. Given that optimal health and longevity may be reached with a plant-based diet and that such a diet is also an ethical, compassionate, and environmentally sensible option, there seem to be few reasons not to eat vegetarian diet as part of a comprehensive plan for long-term health.

Was this page useful?
Related & Popular
Vegetarian Life Span: Can This Diet Help You Live Longer?