For decades, the narrative around healthy aging has largely championed plant-based diets, with vegetarianism and veganism often presented as the gold standard for longevity. A new study from China, however, is challenging that assumption—at least for the very old. The research suggests that for people aged 80 and above, particularly those who are underweight, eating meat may significantly improve the odds of becoming a centenarian.
The Study at a Glance
The research, led by a team from Fudan University in Shanghai, was published in the American Journal of Clinical Nutrition. Scientists analyzed data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS), one of the largest studies on older adults in the world. The cohort included 5,203 participants who were at least 80 years old in 1998 and free of cardiovascular disease, diabetes, and cancer at the start of the study. Over a 20-year follow-up period, 1,459 participants reached the age of 100, while 3,744 died before reaching that milestone.
Approximately 80 percent of the participants reported eating meat, while the remaining 20 percent followed plant-focused diets, including vegetarians, pescatarians, and vegans.
The Key Finding: Weight Matters
The study's headline result is striking: overall, meat eaters were more likely to reach 100 years of age than their vegetarian, pescatarian, or vegan counterparts. However, this difference was statistically significant only when body weight was taken into account.
Among vegetarians with a body mass index (BMI) below 18.5—classified as underweight—24 percent reached the age of 100. In contrast, nearly 30 percent of underweight meat eaters became centenarians, with the likelihood rising further among those who reported eating meat daily. For participants with a BMI above 18.5, the difference in longevity between meat eaters and non-meat eaters disappeared entirely.
A separate analysis by sex revealed that the association was particularly pronounced among women. Female meat eaters were more likely to reach 100 than female vegetarians, while no significant link was found between vegetarianism and longevity among men. The researchers also found that daily meat consumption was associated with a 44 percent higher likelihood of reaching 100 in the underweight group, an association that did not appear in normal-weight or overweight participants.
Why Might Meat Help the Very Old?
The researchers propose a biological explanation rooted in the nutritional needs of aging bodies. As people grow older, they face a heightened risk of malnutrition, muscle wasting (sarcopenia), and bone fragility. Animal proteins provide essential amino acids that help build and maintain muscle mass and bone strength—benefits that may be especially critical for underweight older adults.
Kaiyue Wang, a lead author of the study, noted that older adults tend to have weaker bones and recover poorly after surgery, making their nutritional status a particular concern. The study's findings align with a growing body of research emphasizing the importance of adequate protein intake for healthy aging and the preservation of muscle mass.
Crucially, the study did not find that meat alone was responsible for longevity. Participants who consumed large amounts of vegetables alongside grains and legumes tended to have higher longevity overall, regardless of whether they ate meat. In fact, vegetarians who consumed fish, dairy, or eggs had a similar chance of reaching 100 as meat eaters, suggesting that adequate calorie and nutrient intake—rather than meat specifically—may be the decisive factor.
A Nuanced Picture
The study's authors are careful to frame their findings within a broader context. They emphasize that dietary recommendations for the very old should prioritize balance and adequate nutrition rather than the strict avoidance of animal-based foods, especially for those who are underweight.
Chloe Casey, a lecturer in nutrition at Bournemouth University, offered a similar perspective: "Nutritional priorities shift in later life; the goal becomes preserving muscle mass, preventing weight loss, and ensuring every bite delivers sufficient nutrients". She added that there is no single ideal diet for every life stage—a fiber-rich plant-based diet may suit a person in their forties, while someone in their nineties may need higher calories and protein to avoid malnutrition.
Limitations and Considerations
The study has important limitations. The data come from an exclusively Chinese population with specific dietary habits, so the results may not be fully generalizable to other populations. The observational nature of the research also means it cannot establish causation—it can only identify associations. Furthermore, the study did not analyze the types of meat consumed, leaving open the question of whether the source and quality of meat matter.
The Bottom Line
This study adds a significant wrinkle to the conventional wisdom that plant-based diets are universally superior for longevity. For the very old—particularly those who are underweight—meat may play a protective role by supplying the protein and nutrients needed to maintain muscle and bone health. Yet the broader message is one of balance: a diet rich in vegetables, grains, and legumes remains beneficial at any age, and the best nutritional strategy may depend less on rigid dietary labels and more on the specific needs of the individual at their particular stage of life.