system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is there no consensus on what the optimal human diet should consist of?

Some swear on a strict vegan diet, others insist that meat is essential. Some say that so called "healthy oils" are required by the body and then there are those who don't consume them at all.
gpt
For the same reason that 5+5=10 and 7+3=10. There is more than one way to skin a cat. 

And other such sayings. Also, the body is incredibly complex, so if anyone says they know with great certainty what the body needs, they are lying. We can make educated guesses based on correlational and historical data, but we don't know for sure.