Worth The Weight by Mara Jacobs

Lizzie Hampton is literally a shadow of her former self. Having lost half her body weight, she’s headed to her small hometown to test out her new body on an old flame. Just a harmless fling to get her self confidence back before she returns to
the city and the new man in her life.

Publisher Description

But Lizzie’s plan has a few bumps in the road.

Finn Robbins can’t believe Liz is back in town. Desperate to be the holder of her innocence eighteen years ago, he never got the chance. Now she’s back and he can finally check her off his to do list.

But her friends, his son, and the mysterious Annie may have something to say about that.