Life expectancy for those who ate a plant-based diet for 17 years showed they lived for 3.6 years longer.
Eating red and particularly processed meats on a daily basis was linked to rising mortality rates.
A US study of more than 1.5 million people found all-cause mortality is higher for those who eat meat regularly.
As part of the research, physicians from Mayo Clinic in Arizona analysed six studies that showed the effects of meat and vegetarian diets on mortality.
Primary care physicians were then given evidence-based guidance about whether they should discourage patients from eating meat.
Their recommendation was that physicians should advise patients to limit animal products when possible and consume more plants than meat.
Prof Brookshield Laurent, from the department of family medicine and clinical sciences at New York Institute of Technology College of Osteopathic Medicine, said: “This data reinforces what we have known for so long - your diet has great potential to harm or heal.
“This clinical-based evidence can assist physicians in counseling patients about the important role diet plays, leading to improved preventive care, a key consideration in the osteopathic philosophy of medicine.”
Also, while findings for U.S and European populations differed to an extent, the data found steep rises in mortality - even during the smallest increases in red meat consumption.
As part of the same 2014 study, more than one million people were followed over a number of different yearly time spans - ranging from five and a half years to 28 years.
Researchers considered the link between eating processed meat like bacon, sausage, salami, hot dogs and ham on their diet as well as unprocessed red meat like pork, lamb and unsalted beef.
It was discovered that processed meat significantly increased the risk of all cause mortality - with possible links to cardiovascular disease and ischemic heart disease.
A further review of more than 500,000 participants also found that those with a very low meat intake had a decreased risk of 25 percent to nearly 50 percent of all-cause mortality compared with those with a high meat intake.
Prof Laurent added: “This clinical-based evidence can assist physicians in counselling patients about the important role diet plays, leading to improved preventive care, a key consideration in the osteopathic philosophy of medicine.”
The journal, called “Is Meat Killing Us,” was published today in the Journal of the American Osteopathic Association.