The dietary pattern with the strongest longevity evidence, the Mediterranean diet, is not vegan or vegetarian. It is predominantly plant-based but includes fish, poultry, eggs, dairy, and occasional red meat. Blue Zone populations that include the longest-lived people on earth are not exclusively plant-eating: Sardinians eat pecorino cheese and lamb, Nicoyans eat pork and eggs, and Seventh-day Adventists who eat some fish have better longevity outcomes than those who eat strictly plant-based diets.
What the Evidence Actually Supports
The consistent finding across longevity research is that the proportion of whole plant foods matters profoundly, and that ultra-processed food and processed meat are the primary dietary contributors to disease and early mortality. Eliminating unprocessed fish, eggs, and moderate amounts of quality meat while replacing them with ultra-processed plant-based products does not produce the longevity benefit that characterises Mediterranean and Blue Zone dietary patterns.
The Practical Recommendation
Fill two-thirds to three-quarters of your plate with whole plant foods: vegetables, legumes, whole grains, fruits, nuts, and seeds. Fill the remainder with quality animal protein including fish, eggs, and unprocessed meat. Cook with extra-virgin olive oil. Avoid ultra-processed foods regardless of whether they are plant-based or animal-based. This is the dietary pattern that converges with the evidence for longevity, metabolic health, cognitive function, and body composition across all major research lines.