Obviously don't do that for two obvious reasons (which I am highlighting just to be technically correct and to entertain ourselves):

1) Socially, not good idea. We are social creatures, and want to be accepted as a part of healthy group of our own species.

2) Eating your own kind more likely to transmit diseases, so less healthy.

Also cows and sheep have 99.99% same chemical composition as you, you don't really need to go that far, and any additional benefits (if any) are below statistical noise, but two downsides above are huge.