Vegetarian diets are often praised as a smart path to better health and a longer life, but a new large study suggests the picture is more complicated in very old age. Researchers looking at older adults in China found that people who avoided animal products were less likely to reach 100 than those who ate a mix of plant and animal foods. It is the kind of result that challenges a simple idea many of us carry around, that more plant based automatically means more years.
The study followed 5,203 adults aged 80 and up and drew on a long running national research project that has tracked healthy aging since the late 1990s. The findings were published in 2025 in The American Journal of Clinical Nutrition, and the researchers focused on a straightforward question. How do different eating patterns relate to the chances of becoming a centenarian.
To explore that, the team compared 1,459 people who made it to 100 with 3,744 participants who died before their 100th birthday. Participants were grouped as omnivores or vegetarians, and the vegetarian group was split further into pescatarians, ovo lacto vegetarians, and vegans. That breakdown matters because it highlights the difference between diets that still include some animal derived foods and those that cut them out entirely.
Overall, the vegetarian group had lower odds of reaching 100 than the omnivores who served as the comparison group. The sharpest difference appeared among vegans, who had the lowest likelihood of becoming centenarians. In contrast, pescatarians and ovo lacto vegetarians did not show meaningful differences from meat eaters, suggesting that modest inclusion of fish, eggs, or dairy may help older adults meet nutritional needs without undermining the benefits of plant forward eating.
The researchers also flagged body weight as an important part of the story. Among participants who were undernourished, vegetarian eating patterns were linked with a notably lower chance of reaching 100. That may reflect how vulnerable the oldest adults can be to nutritional gaps when diets become restrictive, especially if appetite is reduced or overall calorie intake is already low.
None of this means plant based eating is suddenly a bad idea. Plant rich diets are widely associated with lower risks of chronic conditions like heart disease, diabetes, and obesity earlier in life. The point here is that extreme restriction in late life may carry different tradeoffs, including concerns around malnutrition and bone health, which the study authors also noted.
With the global number of people over 80 expected to rise dramatically by 2050, figuring out what truly supports healthy aging is becoming more urgent. What do you think matters most in an older person’s diet, balance, protein, variety, or something else, and have you seen it play out in your own family, share your thoughts in the comments.
