"They don't want her to get a reputation. Now she's been on lots of hikes and there are hardly any marathon drinking sessions anymore.
"She's almost vegan now, although she does lapse occasionally."
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Meanwhile, the Hunger Games actress has enjoyed a number of low-key dates with Aziz Ansari, and despite her reluctance to commit to a relationship, the Master Of None star is happy to make the 300 mile trip from New York to where she's filming in Canada in order to be there for her.
A source told Heat magazine: "Aziz has been to Montreal three times this summer to visit Jen.
"He knows she is hesitant to officially date him, so he makes it very easy for her.
"If it takes two years of being at her beck and call before she realises she needs him in her life, so be it.
"It's friends with benefits at this stage, but there's definite potential for something serious."
- Bang! Showbiz