Rules of chemistry and physics are the same throughout the Universe.
The same table of elements exist and apply.
As the basis for biology we can assume the same.
This implies that most species of "Them" would be carbon based life with similar structure and life systems such as found on Earth. Most would likely have bi-lateral symmetry of body design and many quite likely also be very human~humanoid in appearance.
Not only might they be able to eat our food types, but they may have habitats in our Solar System we haven't(can't yet) detect where they grow some of their own.
I've heard that PNW geoduck is a prized and valuable gourmet delicacy in demand at places like Alpha Centauri B4, Arcturus 5, and Tau Ceti 3.