The body burns energy to carry out the exercises you are doing while in the gym and after your workout. The main goal of a post-workout meal is to get the adequate nutrients and energy that will support proper recovery and muscle repair.
A post workout meal is recommended to replace your energy stores and promote muscle fibre repairs. For info on what you should eat after a workout, read this great article on post-workout meals.
If you’re a Fernwood member, you can also find loads of great recipes in MyFernwood.