Humans are a lot more alike than they are different.

The "everyone is bioindividual/different diets work for different people" message is largely a scam pushed to sow confusion.

Can you name another animal in nature where different individuals within the species have a different optimal diet?

Of course not. Every species has a clear optimal diet. Only humans have gotten too smart for their own good and forgotten this. 
https://youtu.be/j1cqNDDG4aA
https://youtu.be/Q_HkQS12jCI