Research suggests that eating meat may be linked to a lower risk of dementia and a higher likelihood of living to 100, but there are conflicting findings and potential caveats. Some studies indicate that vegetarians over 80 may be less likely to reach 100, while others suggest that a specific diet may have varying effects on longevity and cancer risk. The relationship between diet and health outcomes, including dementia and longevity, appears to be complex and not fully understood.