On wheels, perhaps, they keep people going (5)

I believe the answer is:

meals

I'm a little stuck... Click here to teach me more about this clue!

'on wheels' is the definition.
Although both the answer and definition are plural nouns, I don't understand how one could define the other.

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for meals that I've seen before include "Breakfast, dinner and tea" , "Collations" , "Repasts" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app