The most common and most likely answer to this crossword clue is the 11 letter word RESTAURANTS
I've seen this crossword clue in The Daily Telegraph
R
E
S
T
A
U
R
A
N
T
S
More clues leading to the result RESTAURANTS
Buddy explains!
The straight part
We know that "We usually leave them pounds heavier and pounds lighter" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case we usually leave them pounds heavier and pounds lighter = restaurants.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does RESTAURANTS mean?
RESTAURANTS noun- An eating establishment in which diners are served food, usually by waiters at their tables but sometimes (as in a fast food restaurant) at a counter.