To say that someone eats well in Engpsh, you can say that they "eat a lot" or "eat pke a horse". Alternatively, you can say that they "have a big appetite" or "enjoy their food".

For example:

He eats a lot, I don't know where he puts it all.
She eats pke a horse, I'm always impressed by how much she can eat.
He has a big appetite, he always seems to be hungry.
She enjoys her food, it's always a pleasure to eat with her.