Carl Lewis even switched to vegan diet since 1990. Next year he achieved 100m PB of 9.86; and 8.87 in Long Jump, all-time 3th best. Edit:However, I believe any vegan diet should be supplemented with some essential nutrients including methionine, vitamin B12, vitamin D3, and selenium.
On the other hand, I recently revised my knowledge in food contamination. EFSA (European Food Safety Agency) warned on pesticide misuse most often detected in the wheat, rice, peppers, bananas, table grapes, virgine olive oil etc. Also, a notable portion of eggs were plagued by fipronil. Source: the 2018 report,
https://efsa.onlinelibrary.wiley.com...LRESIDUES-DATA (p. 45-46; 53-54).