Do you live longer on a vegetarian or plant-based diet?
A high-quality plant-based diet is associated with less premature death. However, eating strictly vegetarian or vegan has not been proven to be better than a varied diet that occasionally includes meat or fish.
A healthy plant-based eating pattern is associated with a lower risk of premature death. Older Chinese adults who ate the most fresh plant-based foods -- think fruit, vegetables, legumes, nuts and tea -- had a 19% lower chance of dying than those who ate the least of these foods1. Vegetarians also show a lower risk of death from cardiovascular disease across multiple studies, probably due to lower cholesterol, a healthier weight and higher antioxidant intake2,3.
Yet the picture is more nuanced than 'plant-based always wins'. When vegetarians are compared with health-conscious non-vegetarians who occasionally eat meat, the difference in mortality from most cancers and stroke disappears2. A healthy lifestyle in general therefore carries more weight than simply cutting out meat. A recent review study also finds no clear advantage of a fully vegetarian diet over a flexitarian one. Of the well-known regions famous for an exceptionally high number of centenarians, only one has a population that eats predominantly vegetarian4.
The quality of your plant-based food turns out to be decisive, not simply the quantity. A plant-based diet high in preserved vegetables and sugar was actually associated with 17% higher mortality1. Fresh and unprocessed protects; processed and sweetened does not. This distinction matters more than the label 'vegetarian'.
In vegans, the overall mortality rate in available studies is comparable to that of vegetarians and of people who eat meat occasionally5. Among adults over eighty in China, a vegetarian or vegan diet was actually associated with a lower chance of reaching one hundred years of age, particularly in people who were underweight6. At an advanced age, a varied diet containing both animal and plant-based foods appears to be better for an exceptionally long life.
For certain groups, a strictly vegan diet carries concrete risks. Deficiencies in vitamin B12, vitamin D, omega-3 fatty acids, iron, calcium and zinc have been reported in children, pregnant women and older adults5,6,3. Supplements are essential for these groups. That is not a reason to avoid plant-based eating, but it is a reason to pay close attention to it.
All studies are observational, meaning they reveal associations but cannot prove cause and effect. The populations studied vary considerably: China, Europe and North America. Randomised trials with mortality as an endpoint do not exist.