Jenny Alexander 
How to Get the Body you Want by Peony Pinker [EPUB ebook] 

It »s winter and the Pinkers are out of shape – so Dad decides to use
the whole
family to test out his ideas for a new fit-in-four weeks diet book. But
after a few weeks of early
morning runs and cardboard flavoured ready meals, (meaning Peony needs
chips and double helpings of pudding at lunch every day to make up)
Peony »s become so unfit can barely walk up the
hill home. And she »s supposed to be climbing Mount Snowdon in just a
few weeks! Can Gran
get the family back on track with some wise words and common sense?
Hilarious family comedy with a self-help twist.