Windows Need help on programming a food system using sprite sheets


So with helps from you guys and couple videos on youtube, i made the inventory system i want. Now I just cant think of a way to implement a food system bc im using a sprite sheet and not objects of different foods... I want to do something like if your mouse is over the item in inventory ( which i already made), it checks if its a food item. And if it is a food, press A and consume it and add a certain amount to your hunger bar. If anyone has an idea, please teach me how to do this! I used ds_list for creating my list of objects. Thanks!