They might share a lot or might share nothing. Autism is an umbrella diagnosis over a wide range of behaviors and support needs. Diagnostically, it currently has a 1-3 scale across two broad support areas, with one being low support needs and 3 being high support needs. (From the DSM.)

That said, the reasons for autism are not well understood, and there may be many different root causes that lead to the umbrella diagnosis.

Additionally, experiences vary widely -- some autistic folks do not ever feel hungry and must be reminded to eat (or build support systems for it). Others do not ever feel full and must be reminded to not eat (or build support systems for it). Interoception (the perception of your body's internal signals) is impaired for many autistic folks.

Some of us experience misophonia, and get extreme fight or flight responses to audio signals -- personally, I get extremely agitated if I hear someone eating with their mouth open. (To be clear, it's not annoyance. It's fear/anger/hate/danger sense.)