No we don't. There is no bonafide evidence of this.

https://pubmed.ncbi.nlm.nih.gov/28040519/

"Following extensive adjustment for potential confounding factors there was no significant difference in all-cause mortality for vegetarians versus non-vegetarians [HR=1.16 (95% CI 0.93-1.45)]. There was also no significant difference in mortality risk between pesco-vegetarians [HR=0.79 (95% CI 0.59-1.06)] or semi-vegetarians [HR=1.12 (95% CI 0.96-1.31)] versus regular meat eaters. We found no evidence that following a vegetarian diet, semi-vegetarian diet or a pesco-vegetarian diet has an independent protective effect on all-cause mortality. "

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4691673/

"United Kingdom–based vegetarians and comparable nonvegetarians have similar all-cause mortality."

I could provide many other studies as well.

You could then likely counter with many studies that suggest the opposite, which would mean that there is no conclusive, consistent evidence.