Studies on longevity in connection with diet and lifestyle were undertaken as early as the 16th century. Two relatively recent studies tested independently from each other the impact of calorie restriction on health and mortality in rhesus monkeys. Both came up with opposite results.
One study published in the Journal of the American Medical Association (JAMA) found evidence that vegetarians have a slightly better chance at living longer than omnivores. So, should we all consider becoming vegetarians for the sake of a longer life? Not necessarily.