Today we got a promo pic for Jolin's upcoming book about dietetics. According to books.tw it will be released on July 13th!

Here's its title: 養瘦: Jolin能吃能睡又能瘦的健美飲食調養法. It has 224 pages and contains advices from Jolin about losing weight and how to stay thin as well.

Quick Summary of the text available on books.tw (thanks to pommy@alaninternational):

[Jolin will teach you to "eat, sleep, and still be skinny" tips for your daily life.
She talks about how her sister slimmed down 1 month after giving birth.
Jolin actually has a fat body, so she's not naturally slim. She had to work her hardest to get her body to where she wants it.
She will talk about her 20 tips to slim down.]

Source: baidu, jolinlove520