Vegetarian diets are often linked to better long-term health, but new research from China suggests the relationship between diet and longevity may be more complicated than previously thought. A study published in The American Journal of Clinical Nutrition found that women who ate meat were more likely to reach the age of 100 than female vegetarians in a specific subgroup: those who were underweight in later life.

The researchers found no significant association between vegetarianism and reaching 100 among men. They also found that women who followed vegetarian diets but included foods such as fish, eggs or dairy had a similar likelihood of reaching 100 as women who ate meat.

The findings do not show that eating meat extends life. Instead, they highlight how nutritional needs, body weight, and the challenges of ageing may influence the relationship between diet and longevity.

What Did the Study Find About Meat Consumption and Longevity?

The study drew on data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS), a long-running research project examining health and aging among older adults in China.

Researchers compared 1,459 centenarians—people who had reached 100—with 3,744 participants in their 80s and 90s who had not reached that age. The analysis examined whether vegetarian diets were associated with differences in the likelihood of becoming a centenarian.

One of the most notable findings concerned women who were underweight. According to the researchers, underweight women who consumed meat daily had a 44% higher likelihood of reaching 100 than their vegetarian counterparts.

However, this association was not statistically significant among women with normal weight or those who were overweight. Researchers also found no significant association between vegetarianism and longevity among men.

These distinctions are important because they suggest that the relationship between diet and exceptional longevity may depend on a person’s nutritional status rather than whether they eat meat alone.

The study was observational, meaning it identified associations rather than demonstrating cause and effect. It therefore cannot establish that meat consumption directly increases a woman’s chances of reaching 100.

Why Might Body Weight Matter More in Older Adults?

Body weight can have a different significance in very old adults than it does in younger populations.

While excess body fat is associated with several chronic health conditions, being underweight in old age can indicate inadequate food intake, muscle loss or underlying illness. Older adults may also face reduced appetite, difficulties chewing or swallowing, and changes in how their bodies absorb and use nutrients.

These challenges can make it harder to maintain muscle mass and physical strength.

The importance of adequate nutrition

As people age, preserving muscle becomes increasingly important for mobility, balance, and independence. Insufficient energy or protein intake can contribute to muscle loss, a process associated with frailty and a greater risk of falls.

For an older adult who is underweight, a diet that provides enough calories, protein, vitamins and minerals may be particularly important.

Meat can supply high-quality protein, vitamin B12, iron and zinc. However, these nutrients are also available through other foods, including eggs, dairy products, legumes and fortified foods, depending on the nutrient and dietary pattern.

The study’s findings are therefore consistent with the possibility that nutritional adequacy matters more than a simple distinction between vegetarian and meat-eating diets.

Does This Mean Vegetarian Diets Are Unhealthy?

No. The research does not overturn the broader evidence supporting well-planned vegetarian and plant-rich diets.

Dietary patterns that emphasize vegetables, fruits, whole grains, legumes, nuts, and seeds have been associated with lower risks of several chronic diseases, including cardiovascular disease and type 2 diabetes.

The key distinction is between a dietary pattern that supplies all essential nutrients and one that does not adequately meet a person’s needs.

Vegetarian diets can provide sufficient protein and essential nutrients when planned appropriately. Foods such as beans, lentils, chickpeas, dairy products, eggs, nuts and seeds can contribute to protein intake. Vitamin B12 requires particular attention in diets that exclude animal products, often through fortified foods or supplements.

The Chinese study also found that vegetarians who consumed fish, eggs, or dairy had a similar likelihood of reaching 100 as meat eaters. This suggests that the nutritional composition of a diet may be more informative than the vegetarian label alone.

It is also important to distinguish between different types of meat. Processed meats, such as bacon and sausages, and high consumption of red meat have been associated with certain health risks. The findings do not suggest that increasing meat consumption, particularly processed meat, is a proven way to extend life.

What Are the Limitations of the Research?

Although the study offers useful insights into nutrition and ageing, several limitations should shape how its findings are interpreted.

First, the study cannot prove causation. Researchers observed dietary patterns and longevity outcomes but did not randomly assign participants to eat meat or follow vegetarian diets. Other differences between the groups could help explain the results.

Second, diet was assessed in old age. The researchers acknowledged that they did not account for changes in eating habits throughout participants’ lives. A person’s current diet may not reflect their long-term nutritional history.

Third, the findings may not apply equally to everyone. The participants were older adults in China, and dietary habits, healthcare access, genetics and living conditions can differ across populations.

Finally, reaching 100 is not the same as measuring overall health. A study focused on exceptional longevity does not necessarily show which diet best supports quality of life, physical function or freedom from disease over an entire lifespan.

The reported 44% difference also applies specifically to underweight women in the study. It should not be interpreted as evidence that all women who eat meat have a greater chance of becoming centenarians.

How Can Older Adults Eat for Healthy Ageing?

Rather than treating the findings as a reason to abandon vegetarian diets or increase meat consumption, older adults can use them as a reminder to prioritize adequate nutrition.

Helpful approaches include the following:

• Get enough protein: Include suitable sources such as lentils, beans, dairy, eggs, fish or lean meat, according to individual dietary preferences.
• Maintain a healthy weight: Unintentional weight loss or persistent low body weight warrants discussion with a healthcare professional.
• Eat a varied diet: Combine protein-rich foods with vegetables, fruits, whole grains and sources of healthy fats.
• Pay attention to nutrient deficiencies: Older adults may need particular attention to vitamin B12, vitamin D, calcium and iron, depending on their diets and medical circumstances.
• Adapt meals to individual needs: Appetite, digestive issues, chronic conditions and medication use can influence nutritional requirements.

Older adults who are losing weight or struggling to eat enough should seek advice from a healthcare professional or registered dietitian rather than making major dietary changes based on a single study.

The Bottom Line: Longevity Depends on More Than Meat

The Chinese research adds an important qualification to the discussion about diet and longevity. Among underweight older women, daily meat consumption was associated with a greater likelihood of reaching 100, but the same relationship was not observed in women of normal weight or those who were overweight, or among men.

The findings do not establish that meat itself extends life. They instead point to the importance of considering nutritional status, adequate calorie intake and the ability to maintain muscle mass as people age.

For people hoping to live longer and remain healthy, the practical message is not that everyone should eat meat. It is that dietary choices should provide sufficient energy and essential nutrients, while taking age, body weight and individual health needs into account.

A balanced, well-planned vegetarian diet can still support healthy aging. For older adults who are underweight or at risk of malnutrition, ensuring adequate nutrition may be especially important—regardless of whether that nutrition comes from plant-based foods, animal products or a combination of both.